Guide to the Secure Configuration of Red Hat Enterprise Linux 6

catalog, not a checklist, · ntpserver

$ sudo rhn_register
$ sudo rpm --import /media/cdrom/RPM-GPG-KEY
# The two fingerprints below are retrieved from https://access.redhat.com/security/team/key
readonly REDHAT_RELEASE_2_FINGERPRINT="567E 347A D004 4ADE 55BA 8A5F 199E 2F91 FD43 1D51"
readonly REDHAT_AUXILIARY_FINGERPRINT="43A6 E49C 4A38 F4BE 9ABF 2A53 4568 9C88 2FA6 58E0"
# Location of the key we would like to import (once it's integrity verified)
readonly REDHAT_RELEASE_KEY="/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release"

RPM_GPG_DIR_PERMS=$(stat -c %a "$(dirname "$REDHAT_RELEASE_KEY")")

# Verify /etc/pki/rpm-gpg directory permissions are safe
if [ "${RPM_GPG_DIR_PERMS}" -le "755" ]
then
  # If they are safe, try to obtain fingerprints from the key file
  # (to ensure there won't be e.g. CRC error)
  IFS=$'\n' GPG_OUT=($(gpg --with-fingerprint "${REDHAT_RELEASE_KEY}"))
  GPG_RESULT=$?
  # No CRC error, safe to proceed
  if [ "${GPG_RESULT}" -eq "0" ]
  then
    for ITEM in "${GPG_OUT[@]}"
    do
      # Filter just hexadecimal fingerprints from gpg's output from
      # processing of a key file
      RESULT=$(echo ${ITEM} | sed -n "s/[[:space:]]*Key fingerprint = \(.*\)/\1/p" | tr -s '[:space:]')
      # If fingerprint matches Red Hat's release 2 or auxiliary key import the key
      if [[ ${RESULT} ]] && ([[ ${RESULT} = "${REDHAT_RELEASE_2_FINGERPRINT}" ]] || \
                             [[ ${RESULT} = "${REDHAT_AUXILIARY_FINGERPRINT}" ]])
      then
        rpm --import "${REDHAT_RELEASE_KEY}"
      fi
    done
  fi
fi

gpgcheck=1
sed -i 's/gpgcheck=.*/gpgcheck=1/g' /etc/yum.conf

gpgcheck=0
sed -i 's/gpgcheck=.*/gpgcheck=1/g' /etc/yum.repos.d/*

$ sudo yum install aide
yum -y install aide

$ sudo /usr/sbin/aide --init
$ sudo cp /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz
$ sudo /usr/sbin/aide --check
/usr/sbin/aide --init

05 4 * * * root /usr/sbin/aide --check
echo "05 4 * * * root /usr/sbin/aide --check" >> /etc/crontab

$ rpm -qVa
$ rpm -qf FILENAME
$ sudo rpm --setperms PACKAGENAME

# Declare array to hold list of RPM packages we need to correct permissions for
declare -a SETPERMS_RPM_LIST

# Create a list of files on the system having permissions different from what
# is expected by the RPM database
FILES_WITH_INCORRECT_PERMS=($(rpm -Va --nofiledigest | grep '^.M'))

# For each file path from that list:
# * Determine the RPM package the file path is shipped by,
# * Include it into SETPERMS_RPM_LIST array

for FILE_PATH in "${FILES_WITH_INCORRECT_PERMS[@]}"
do
	RPM_PACKAGE=$(rpm -qf "$FILE_PATH")
	SETPERMS_RPM_LIST=("${SETPERMS_RPM_LIST[@]}" "$RPM_PACKAGE")
done

# Remove duplicate mention of same RPM in $SETPERMS_RPM_LIST (if any)
SETPERMS_RPM_LIST=( $(echo "${SETPERMS_RPM_LIST[@]}" | sort -n | uniq) )

# For each of the RPM packages left in the list -- reset its permissions to the
# correct values
for RPM_PACKAGE in "${SETPERMS_RPM_LIST[@]}"
do
	rpm --setperms "${RPM_PACKAGE}"
done

$ rpm -Va | grep '^..5'
$ rpm -qf FILENAME
$ sudo yum reinstall PACKAGENAME
$ sudo rpm -Uvh PACKAGENAME
PRELINKING=no
$ sudo /usr/sbin/prelink -ua
#
# Disable prelinking altogether
#
if grep -q ^PRELINKING /etc/sysconfig/prelink
then
  sed -i 's/PRELINKING.*/PRELINKING=no/g' /etc/sysconfig/prelink
else
  echo -e "\n# Set PRELINKING=no per security requirements" >> /etc/sysconfig/prelink
  echo "PRELINKING=no" >> /etc/sysconfig/prelink
fi

#
# Undo previous prelink changes to binaries
#
/usr/sbin/prelink -ua

$ mount -t ext4 | awk '{print $3}'

# NOTE: Run-time reconfiguration of partitions' mount options is not possible.
# After performing this remediation be sure to also subsequently reboot the
# system as soon as possible for the remediation to take the effect!

# Shortened ID for frequently used character class
SP="[:space:]"

# Load /etc/fstab's content with LABEL= and UUID= tags expanded to real
# device names into FSTAB_REAL_DEVICES array splitting items by newline
IFS=$'\n' FSTAB_REAL_DEVICES=($(findmnt --fstab --evaluate --noheadings))

for line in ${FSTAB_REAL_DEVICES[@]}
do
    # For each line:
    # * squeeze multiple space characters into one,
    # * split line content info four columns (target, source, fstype, and
    #   mount options) by space delimiter
    IFS=$' ' read TARGET SOURCE FSTYPE MOUNT_OPTIONS <<< "$(echo $line | tr -s ' ')"

    # Filter the targets according to the following criteria:
    # * don't include record for root partition,
    # * include the target only if it has the form of '/word.*' (not to include
    #   special entries like e.g swap),
    # * include the target only if its source has the form of '/dev.*'
    #   (to process only local partitions)
    if [[ ! $TARGET =~ ^\/$ ]] 		&&	# Don't include root partition
       [[ $TARGET =~ ^\/[A-Za-z0-9_] ]] &&	# Include if target =~ '/word.*'
       [[ $SOURCE =~ ^\/dev ]]			# Include if source =~ '/dev.*'
    then

        # Check the mount options column if it doesn't contain 'nodev' keyword yet
        if ! grep -q "nodev" <<< "$MOUNT_OPTIONS"
        then
            # Check if current mount options is empty string ('') meaning
            # particular /etc/fstab row contain just 'defaults' keyword
            if [[ ${#MOUNT_OPTIONS} == "0" ]]
            then
                # If so, add 'defaults' back and append 'nodev' keyword
                MOUNT_OPTIONS="defaults,nodev"
            else
                # Otherwise append just 'nodev' keyword
                MOUNT_OPTIONS="$MOUNT_OPTIONS,nodev"
            fi

            # Escape possible slash ('/') characters in target for use as sed
            # expression below
            TARGET_ESCAPED=${TARGET//$'/'/$'\/'}
            # This target doesn't contain 'nodev' in mount options yet (and meets
            # the above filtering criteria). Therefore obtain particular /etc/fstab's
            # row into FSTAB_TARGET_ROW variable separating the mount options field with
            # hash '#' character
            FSTAB_TARGET_ROW=$(sed -n "s/\(.*$TARGET_ESCAPED[$SP]\+$FSTYPE[$SP]\+\)\([^$SP]\+\)/\1#\2#/p" /etc/fstab)
            # Split the retrieved value by the hash '#' delimiter to get the
            # row's head & tail (i.e. columns other than mount options) which won't
            # get modified
            IFS=$'#' read TARGET_HEAD TARGET_OPTS TARGET_TAIL <<< "$FSTAB_TARGET_ROW"
            # Replace old mount options for particular /etc/fstab's row (for this target
            # and fstype) with new mount options
            sed -i "s#${TARGET_HEAD}\(.*\)${TARGET_TAIL}#${TARGET_HEAD}${MOUNT_OPTIONS}${TARGET_TAIL}#" /etc/fstab

        fi
    fi
done

# Load /etc/fstab's /dev/shm row into DEV_SHM_FSTAB variable separating start &
# end of the filesystem mount options (4-th field) with the '#' character
DEV_SHM_FSTAB=$(sed -n "s/\(.*[[:space:]]\+\/dev\/shm[[:space:]]\+tmpfs[[:space:]]\+\)\([^[:space:]]\+\)/\1#\2#/p" /etc/fstab)

#Rest of script can trash /etc/fstab if $DEV_SHM_FSTAB is empty, check before continuing.
echo $DEV_SHM_FSTAB | grep -q -P '/dev/shm'
if [ $? -eq 0 ]; then
	# Save the:
	# * 1-th, 2-nd, 3-rd fields into DEV_SHM_HEAD variable
	# * 4-th field into DEV_SHM_OPTS variable, and
	# * 5-th, and 6-th fields into DEV_SHM_TAIL variable
	# splitting DEV_SHM_FSTAB variable value based on the '#' separator
	IFS='#' read DEV_SHM_HEAD DEV_SHM_OPTS DEV_SHM_TAIL <<< "$DEV_SHM_FSTAB"

	# Replace occurrence of 'defaults' key with the actual list of mount options
	# for Red Hat Enterprise Linux 6
	DEV_SHM_OPTS=${DEV_SHM_OPTS//defaults/rw,suid,dev,exec,auto,nouser,async,relatime}

	# 'dev' option (not prefixed with 'no') present in the list?
	echo $DEV_SHM_OPTS | grep -q -P '(?<!no)dev'
	if [ $? -eq 0 ]
	then
	        # 'dev' option found, replace with 'nodev'
	        DEV_SHM_OPTS=${DEV_SHM_OPTS//dev/nodev}
	fi

	# at least one 'nodev' present in the options list?
	echo $DEV_SHM_OPTS | grep -q -v 'nodev'
	if [ $? -eq 0 ]
	then
	        # 'nodev' not found yet, append it
	        DEV_SHM_OPTS="$DEV_SHM_OPTS,nodev"
	fi

	# DEV_SHM_OPTS now contains final list of mount options. Replace original form of /dev/shm row
	# in /etc/fstab with the corrected version
	sed -i "s#${DEV_SHM_HEAD}\(.*\)${DEV_SHM_TAIL}#${DEV_SHM_HEAD}${DEV_SHM_OPTS}${DEV_SHM_TAIL}#" /etc/fstab
fi

# Load /etc/fstab's /dev/shm row into DEV_SHM_FSTAB variable separating start &
# end of the filesystem mount options (4-th field) with the '#' character
DEV_SHM_FSTAB=$(sed -n "s/\(.*[[:space:]]\+\/dev\/shm[[:space:]]\+tmpfs[[:space:]]\+\)\([^[:space:]]\+\)/\1#\2#/p" /etc/fstab)

#Rest of script can trash /etc/fstab if $DEV_SHM_FSTAB is empty, check before continuing.
echo $DEV_SHM_FSTAB | grep -q -P '/dev/shm'
if [ $? -eq 0 ]; then
	# Save the:
	# * 1-th, 2-nd, 3-rd fields into DEV_SHM_HEAD variable
	# * 4-th field into DEV_SHM_OPTS variable, and
	# * 5-th, and 6-th fields into DEV_SHM_TAIL variable
	# splitting DEV_SHM_FSTAB variable value based on the '#' separator
	IFS='#' read DEV_SHM_HEAD DEV_SHM_OPTS DEV_SHM_TAIL <<< "$DEV_SHM_FSTAB"

	# Replace occurrence of 'defaults' key with the actual list of mount options
	# for Red Hat Enterprise Linux 6
	DEV_SHM_OPTS=${DEV_SHM_OPTS//defaults/rw,suid,dev,exec,auto,nouser,async,relatime}

	# 'exec' option (not prefixed with 'no') present in the list?
	echo $DEV_SHM_OPTS | grep -q -P '(?<!no)exec'
	if [ $? -eq 0 ]
	then
	        # 'exec' option found, replace with 'noexec'
	        DEV_SHM_OPTS=${DEV_SHM_OPTS//exec/noexec}
	fi

	# at least one 'noexec' present in the options list?
	echo $DEV_SHM_OPTS | grep -q -v 'noexec'
	if [ $? -eq 0 ]
	then
	        # 'noexec' not found yet, append it
	        DEV_SHM_OPTS="$DEV_SHM_OPTS,noexec"
	fi

	# DEV_SHM_OPTS now contains final list of mount options. Replace original form of /dev/shm row
	# in /etc/fstab with the corrected version
	sed -i "s#${DEV_SHM_HEAD}\(.*\)${DEV_SHM_TAIL}#${DEV_SHM_HEAD}${DEV_SHM_OPTS}${DEV_SHM_TAIL}#" /etc/fstab

fi

# Load /etc/fstab's /dev/shm row into DEV_SHM_FSTAB variable separating start &
# end of the filesystem mount options (4-th field) with the '#' character
DEV_SHM_FSTAB=$(sed -n "s/\(.*[[:space:]]\+\/dev\/shm[[:space:]]\+tmpfs[[:space:]]\+\)\([^[:space:]]\+\)/\1#\2#/p" /etc/fstab)

#Rest of script can trash /etc/fstab if $DEV_SHM_FSTAB is empty, check before continuing.
echo $DEV_SHM_FSTAB | grep -q -P '/dev/shm'
if [ $? -eq 0 ]; then
	# Save the:
	# * 1-th, 2-nd, 3-rd fields into DEV_SHM_HEAD variable
	# * 4-th field into DEV_SHM_OPTS variable, and
	# * 5-th, and 6-th fields into DEV_SHM_TAIL variable
	# splitting DEV_SHM_FSTAB variable value based on the '#' separator
	IFS='#' read DEV_SHM_HEAD DEV_SHM_OPTS DEV_SHM_TAIL <<< "$DEV_SHM_FSTAB"

	# Replace occurrence of 'defaults' key with the actual list of mount options
	# for Red Hat Enterprise Linux 6
	DEV_SHM_OPTS=${DEV_SHM_OPTS//defaults/rw,suid,dev,exec,auto,nouser,async,relatime}

	# 'suid' option (not prefixed with 'no') present in the list?
	echo $DEV_SHM_OPTS | grep -q -P '(?<!no)suid'
	if [ $? -eq 0 ]
	then
	        # 'suid' option found, replace with 'nosuid'
	        DEV_SHM_OPTS=${DEV_SHM_OPTS//suid/nosuid}
	fi

	# at least one 'nosuid' present in the options list?
	echo $DEV_SHM_OPTS | grep -q -v 'nosuid'
	if [ $? -eq 0 ]
	then
	        # 'nosuid' not found yet, append it
	        DEV_SHM_OPTS="$DEV_SHM_OPTS,nosuid"
	fi

	# DEV_SHM_OPTS now contains final list of mount options. Replace original form of /dev/shm row
	# in /etc/fstab with the corrected version
	sed -i "s#${DEV_SHM_HEAD}\(.*\)${DEV_SHM_TAIL}#${DEV_SHM_HEAD}${DEV_SHM_OPTS}${DEV_SHM_TAIL}#" /etc/fstab
fi

/tmp     /var/tmp     none     rw,nodev,noexec,nosuid,bind     0 0
# Delete particular /etc/fstab's row if /var/tmp is already configured to
# represent a mount point (for some device or filesystem other than /tmp)
if grep -q -P '.*\/var\/tmp.*' /etc/fstab
then
  sed -i '/.*\/var\/tmp.*/d' /etc/fstab
fi

# Bind-mount /var/tmp to /tmp via /etc/fstab (preserving the /etc/fstab form)
printf "%-24s%-24s%-8s%-32s%-3s\n" "/tmp" "/var/tmp" "none" "rw,nodev,noexec,nosuid,bind" "0 0" >> /etc/fstab

$ find /lib/modules/`uname -r`/kernel/fs -type f -name '*.ko'
install cramfs /bin/true
echo "install cramfs /bin/true" > /etc/modprobe.d/cramfs.conf

install freevxfs /bin/true
echo "install freevxfs /bin/true" > /etc/modprobe.d/freevxfs.conf

install jffs2 /bin/true
echo "install jffs2 /bin/true" > /etc/modprobe.d/jffs2.conf

install hfs /bin/true
echo "install hfs /bin/true" > /etc/modprobe.d/hfs.conf

install hfsplus /bin/true
echo "install hfsplus /bin/true" > /etc/modprobe.d/hfsplus.conf

install squashfs /bin/true
echo "install squashfs /bin/true" > /etc/modprobe.d/squashfs.conf

install udf /bin/true
echo "install udf /bin/true" > /etc/modprobe.d/udf.conf

$ sudo chown root /etc/shadow
chown root /etc/shadow

$ sudo chgrp root /etc/shadow
chgrp root /etc/shadow

$ sudo chmod 0000 /etc/shadow
chmod 0000 /etc/shadow

$ sudo chown root /etc/group
chown root /etc/group

$ sudo chgrp root /etc/group
chgrp root /etc/group

$ sudo chmod 644 /etc/group
chmod 644 /etc/group

$ sudo chown root /etc/gshadow
chown root /etc/gshadow

$ sudo chgrp root /etc/gshadow
chgrp root /etc/gshadow

$ sudo chmod 0000 /etc/gshadow
chmod 0000 /etc/gshadow

$ sudo chown root /etc/passwd
chown root /etc/passwd

$ sudo chgrp root /etc/passwd
chgrp root /etc/passwd

$ sudo chmod 0644 /etc/passwd
chmod 0644 /etc/passwd

/bin
/sbin
/usr/bin
/usr/libexec
/usr/local/bin
/usr/local/sbin
/usr/sbin
$ sudo chmod go-w FILE
DIRS="/bin /usr/bin /usr/local/bin /sbin /usr/sbin /usr/local/sbin /usr/libexec"
for dirPath in $DIRS; do
	find "$dirPath" -perm /022 -exec chmod go-w '{}' \;
done

$ sudo chmod +t DIR
umask 027

var_umask_for_daemons="027"

grep -q ^umask /etc/init.d/functions && \
  sed -i "s/umask.*/umask $var_umask_for_daemons/g" /etc/init.d/functions
if ! [ $? -eq 0 ]; then
    echo "umask $var_umask_for_daemons" >> /etc/init.d/functions
fi

*     hard   core    0
echo "*     hard   core    0" >> /etc/security/limits.conf

$ sudo sysctl -w fs.suid_dumpable=0
fs.suid_dumpable = 0
#
# Set runtime for fs.suid_dumpable
#
/sbin/sysctl -q -n -w fs.suid_dumpable=0

#
# If fs.suid_dumpable present in /etc/sysctl.conf, change value to "0"
#	else, add "fs.suid_dumpable = 0" to /etc/sysctl.conf
#
if grep --silent ^fs.suid_dumpable /etc/sysctl.conf ; then
	sed -i 's/^fs.suid_dumpable.*/fs.suid_dumpable = 0/g' /etc/sysctl.conf
else
	echo -e "\n# Set fs.suid_dumpable to 0 per security requirements" >> /etc/sysctl.conf
	echo "fs.suid_dumpable = 0" >> /etc/sysctl.conf
fi

$ sudo sysctl -w kernel.exec-shield=1
kernel.exec-shield = 1
#
# Set runtime for kernel.exec-shield
#
/sbin/sysctl -q -n -w kernel.exec-shield=1

#
# If kernel.exec-shield present in /etc/sysctl.conf, change value to "1"
#	else, add "kernel.exec-shield = 1" to /etc/sysctl.conf
#
if grep --silent ^kernel.exec-shield /etc/sysctl.conf ; then
	sed -i 's/^kernel.exec-shield.*/kernel.exec-shield = 1/g' /etc/sysctl.conf
else
	echo -e "\n# Set kernel.exec-shield to 1 per security requirements" >> /etc/sysctl.conf
	echo "kernel.exec-shield = 1" >> /etc/sysctl.conf
fi

$ sudo sysctl -w kernel.randomize_va_space=2
kernel.randomize_va_space = 2
#
# Set runtime for kernel.randomize_va_space
#
/sbin/sysctl -q -n -w kernel.randomize_va_space=2

#
# If kernel.randomize_va_space present in /etc/sysctl.conf, change value to "2"
#	else, add "kernel.randomize_va_space = 2" to /etc/sysctl.conf
#
if grep --silent ^kernel.randomize_va_space /etc/sysctl.conf ; then
	sed -i 's/^kernel.randomize_va_space.*/kernel.randomize_va_space = 2/g' /etc/sysctl.conf
else
	echo -e "\n# Set kernel.randomize_va_space to 2 per security requirements" >> /etc/sysctl.conf
	echo "kernel.randomize_va_space = 2" >> /etc/sysctl.conf
fi

sed -i --follow-symlinks "s/selinux=0//gI" /etc/grub.conf
sed -i --follow-symlinks "s/enforcing=0//gI" /etc/grub.conf

SELINUX=enforcing

var_selinux_state="enforcing"

function replace_or_append {
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  # Check sanity of the input
  if [ $# -lt "3" ]
  then
        echo "Usage: replace_or_append 'config_file_location' 'key_to_search' 'new_value'"
        echo
        echo "If symlinks need to be taken into account, add yes/no to the last argument"
        echo "to allow to 'follow_symlinks'."
        echo "Aborting."
        exit 1
  fi

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  if test -L $config_file; then
    sed_command="sed -i --follow-symlinks"
  else
    sed_command="sed -i"
  fi

  # Test that the cce arg is not empty or does not equal CCENUM.
  # If CCENUM exists, it means that there is no CCE assigned.
  if ! [ "x$cce" = x ] && [ "$cce" != 'CCENUM' ]; then
    cce="CCE-${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=${key//[!a-zA-Z]/}

  # If there is no print format specified in the last arg, use the default format.
  if ! [ "x$format" = x ] ; then
    printf -v formatted_output "$format" $stripped_key $value
  else
    formatted_output="$stripped_key = $value"
  fi

  # If the key exists, change it. Otherwise, add it to the config_file.
  if `grep -qi $key $config_file` ; then
    $sed_command "s/$key.*/$formatted_output/g" $config_file
  else
    echo -ne "\n# Per $cce: Set $formatted_output in $config_file" >> $config_file
    echo -ne "\n$formatted_output" >> $config_file
  fi

}

replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state 'CCENUM' '%s=%s'

SELINUXTYPE=targeted

var_selinux_policy_name="targeted"

function replace_or_append {
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  # Check sanity of the input
  if [ $# -lt "3" ]
  then
        echo "Usage: replace_or_append 'config_file_location' 'key_to_search' 'new_value'"
        echo
        echo "If symlinks need to be taken into account, add yes/no to the last argument"
        echo "to allow to 'follow_symlinks'."
        echo "Aborting."
        exit 1
  fi

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  if test -L $config_file; then
    sed_command="sed -i --follow-symlinks"
  else
    sed_command="sed -i"
  fi

  # Test that the cce arg is not empty or does not equal CCENUM.
  # If CCENUM exists, it means that there is no CCE assigned.
  if ! [ "x$cce" = x ] && [ "$cce" != 'CCENUM' ]; then
    cce="CCE-${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=${key//[!a-zA-Z]/}

  # If there is no print format specified in the last arg, use the default format.
  if ! [ "x$format" = x ] ; then
    printf -v formatted_output "$format" $stripped_key $value
  else
    formatted_output="$stripped_key = $value"
  fi

  # If the key exists, change it. Otherwise, add it to the config_file.
  if `grep -qi $key $config_file` ; then
    $sed_command "s/$key.*/$formatted_output/g" $config_file
  else
    echo -ne "\n# Per $cce: Set $formatted_output in $config_file" >> $config_file
    echo -ne "\n$formatted_output" >> $config_file
  fi

}

replace_or_append '/etc/sysconfig/selinux' '^SELINUXTYPE=' $var_selinux_policy_name 'CCENUM' '%s=%s'

$ sudo yum erase setroubleshoot
$ sudo yum erase mcstrans
$ sudo ps -eZ | egrep "initrc" | egrep -vw "tr|ps|egrep|bash|awk" | tr ':' ' ' | awk '{ print $NF }'
$ sudo echo > /etc/securetty

echo > /etc/securetty

$ sudo usermod -s /sbin/nologin SYSACCT
awk -F: '$3 == 0 && $1 != "root" { print $1 }' /etc/passwd | xargs passwd -l

~/.profile
~/.bashrc
sed --follow-symlinks -i 's/\<nullok\>//g' /etc/pam.d/system-auth

$ sudo chage -M 180 -m 7 -W 7 USER
PASS_MIN_DAYS 7

var_accounts_minimum_age_login_defs="7"

grep -q ^PASS_MIN_DAYS /etc/login.defs && \
  sed -i "s/PASS_MIN_DAYS.*/PASS_MIN_DAYS     $var_accounts_minimum_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
    echo "PASS_MIN_DAYS      $var_accounts_minimum_age_login_defs" >> /etc/login.defs
fi

PASS_MAX_DAYS 90

var_accounts_maximum_age_login_defs="90"

grep -q ^PASS_MAX_DAYS /etc/login.defs && \
  sed -i "s/PASS_MAX_DAYS.*/PASS_MAX_DAYS     $var_accounts_maximum_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
    echo "PASS_MAX_DAYS      $var_accounts_maximum_age_login_defs" >> /etc/login.defs
fi

PASS_WARN_AGE 7

var_accounts_password_warn_age_login_defs="7"

grep -q ^PASS_WARN_AGE /etc/login.defs && \
  sed -i "s/PASS_WARN_AGE.*/PASS_WARN_AGE     $var_accounts_password_warn_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
    echo "PASS_WARN_AGE      $var_accounts_password_warn_age_login_defs" >> /etc/login.defs
fi

$ sudo chage -I NUM_DAYS USER
INACTIVE=UNDEFINED_SUB

var_account_disable_post_pw_expiration="35"

grep -q ^INACTIVE /etc/default/useradd && \
  sed -i "s/INACTIVE.*/INACTIVE=$var_account_disable_post_pw_expiration/g" /etc/default/useradd
if ! [ $? -eq 0 ]; then
    echo "INACTIVE=$var_account_disable_post_pw_expiration" >> /etc/default/useradd
fi

auth required pam_faillock.so preauth silent deny=3 unlock_time=604800 fail_interval=900
auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900
account required pam_faillock.so

var_accounts_passwords_pam_faillock_deny="3"

AUTH_FILES[0]="/etc/pam.d/system-auth"
AUTH_FILES[1]="/etc/pam.d/password-auth"

for pamFile in "${AUTH_FILES[@]}"
do

	# pam_faillock.so already present?
	if grep -q "^auth.*pam_faillock.so.*" $pamFile; then

		# pam_faillock.so present, deny directive present?
		if grep -q "^auth.*[default=die].*pam_faillock.so.*authfail.*deny=" $pamFile; then

			# both pam_faillock.so & deny present, just correct deny directive value
			sed -i --follow-symlinks "s/\(^auth.*required.*pam_faillock.so.*preauth.*silent.*\)\(deny *= *\).*/\1\2$var_accounts_passwords_pam_faillock_deny/" $pamFile
			sed -i --follow-symlinks "s/\(^auth.*[default=die].*pam_faillock.so.*authfail.*\)\(deny *= *\).*/\1\2$var_accounts_passwords_pam_faillock_deny/" $pamFile

		# pam_faillock.so present, but deny directive not yet
		else

			# append correct deny value to appropriate places
			sed -i --follow-symlinks "/^auth.*required.*pam_faillock.so.*preauth.*silent.*/ s/$/ deny=$var_accounts_passwords_pam_faillock_deny/" $pamFile
			sed -i --follow-symlinks "/^auth.*[default=die].*pam_faillock.so.*authfail.*/ s/$/ deny=$var_accounts_passwords_pam_faillock_deny/" $pamFile
		fi

	# pam_faillock.so not present yet
	else

		# insert pam_faillock.so preauth & authfail rows with proper value of the 'deny' option
		sed -i --follow-symlinks "/^auth.*sufficient.*pam_unix.so.*/i auth        required      pam_faillock.so preauth silent deny=$var_accounts_passwords_pam_faillock_deny" $pamFile
		sed -i --follow-symlinks "/^auth.*sufficient.*pam_unix.so.*/a auth        [default=die] pam_faillock.so authfail deny=$var_accounts_passwords_pam_faillock_deny" $pamFile
		sed -i --follow-symlinks "/^account.*required.*pam_unix.so/i account     required      pam_faillock.so" $pamFile
	fi
done

password sufficient pam_unix.so existing_options remember=5
password requisite pam_pwhistory.so existing_options remember=5

var_password_pam_unix_remember="5"

if grep -q "remember=" /etc/pam.d/system-auth; then   
	sed -i --follow-symlinks "s/\(^password.*sufficient.*pam_unix.so.*\)\(\(remember *= *\)[^ $]*\)/\1remember=$var_password_pam_unix_remember/" /etc/pam.d/system-auth
else
	sed -i --follow-symlinks "/^password[[:space:]]\+sufficient[[:space:]]\+pam_unix.so/ s/$/ remember=$var_password_pam_unix_remember/" /etc/pam.d/system-auth
fi

umask 027

var_accounts_user_umask="027"

grep -q umask /etc/bashrc && \
  sed -i "s/umask.*/umask $var_accounts_user_umask/g" /etc/bashrc
if ! [ $? -eq 0 ]; then
    echo "umask $var_accounts_user_umask" >> /etc/bashrc
fi

umask 027

var_accounts_user_umask="027"

grep -q umask /etc/profile && \
  sed -i "s/umask.*/umask $var_accounts_user_umask/g" /etc/profile
if ! [ $? -eq 0 ]; then
    echo "umask $var_accounts_user_umask" >> /etc/profile
fi

$ sudo ls -ld /home/USER
$ sudo chmod g-w /home/USER
$ sudo chmod o-rwx /home/USER
$ sudo chown root /etc/grub.conf
chown root /etc/grub.conf

$ sudo chgrp root /etc/grub.conf
chgrp root /etc/grub.conf

$ sudo chmod 600 /boot/grub/grub.conf
chmod 600 /boot/grub/grub.conf

$ grub-crypt --sha-512
password --encrypted password-hash
SINGLE=/sbin/sulogin
grep -q ^SINGLE /etc/sysconfig/init && \
  sed -i "s/SINGLE.*/SINGLE=\/sbin\/sulogin/g" /etc/sysconfig/init
if ! [ $? -eq 0 ]; then
    echo "SINGLE=/sbin/sulogin" >> /etc/sysconfig/init
fi

PROMPT=no

# Ensure value of PROMPT key in /etc/sysconfig/init is set to 'no'
grep -q ^PROMPT /etc/sysconfig/init && \
  sed -i "s/PROMPT.*/PROMPT=no/g" /etc/sysconfig/init
if ! [ $? -eq 0 ]; then
    echo "PROMPT=no" >> /etc/sysconfig/init
fi

# Ensure 'confirm' kernel boot argument is not present in some of
# kernel lines in /etc/grub.conf
sed -i --follow-symlinks "s/confirm//gI" /etc/grub.conf

$ sudo gconftool-2 --direct \
  --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
  --type bool \
  --set /apps/gdm/simple-greeter/banner_message_enable true
# Install GConf2 package if not installed
if ! rpm -q GConf2; then
  yum -y install GConf2
fi

# Enable displaying of a login warning banner in the GNOME Display Manager's
# login screen
gconftool-2 --direct \
            --config-source "xml:readwrite:/etc/gconf/gconf.xml.mandatory" \
            --type bool \
            --set /apps/gdm/simple-greeter/banner_message_enable true

$ sudo gconftool-2 --direct \
  --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
  --type string \
  --set /apps/gdm/simple-greeter/banner_message_text \
  "Text of the warning banner here"

login_banner_text="(N/A)"

# Install GConf2 package if not installed
if ! rpm -q GConf2; then
  yum -y install GConf2
fi

# Expand the login_banner_text value - there was a regular-expression
# matching various banners, needs to be expanded
banner_expanded=$(echo "$login_banner_text" | sed 's/\[\\s\\n\][*+]/ /g;s/\\//g;')

# Set the text shown by the GNOME Display Manager in the login screen
gconftool-2 --direct \
            --config-source "xml:readwrite:/etc/gconf/gconf.xml.mandatory" \
            --type string \
            --set /apps/gdm/simple-greeter/banner_message_text "${banner_expanded}"

login_banner_text="(N/A)"

# There was a regular-expression matching various banners, needs to be expanded
expanded=$(echo "$login_banner_text" | sed 's/\[\\s\\n\][+*]/ /g;s/\\//g;s/[^-]- /\n\n-/g')
formatted=$(echo "$expanded" | fold -sw 80)

cat <<EOF >/etc/issue
$formatted
EOF

printf "\n" >> /etc/issue

$ sudo sysctl -w net.ipv4.conf.default.send_redirects=0
net.ipv4.conf.default.send_redirects = 0
#
# Set runtime for net.ipv4.conf.default.send_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.send_redirects=0

#
# If net.ipv4.conf.default.send_redirects present in /etc/sysctl.conf, change value to "0"
#	else, add "net.ipv4.conf.default.send_redirects = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.default.send_redirects /etc/sysctl.conf ; then
	sed -i 's/^net.ipv4.conf.default.send_redirects.*/net.ipv4.conf.default.send_redirects = 0/g' /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.conf.default.send_redirects to 0 per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.conf.default.send_redirects = 0" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.conf.all.send_redirects=0
net.ipv4.conf.all.send_redirects = 0
#
# Set runtime for net.ipv4.conf.all.send_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.send_redirects=0

#
# If net.ipv4.conf.all.send_redirects present in /etc/sysctl.conf, change value to "0"
#	else, add "net.ipv4.conf.all.send_redirects = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.send_redirects /etc/sysctl.conf ; then
	sed -i 's/^net.ipv4.conf.all.send_redirects.*/net.ipv4.conf.all.send_redirects = 0/g' /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.conf.all.send_redirects to 0 per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.conf.all.send_redirects = 0" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.ip_forward=0
net.ipv4.ip_forward = 0
#
# Set runtime for net.ipv4.ip_forward
#
/sbin/sysctl -q -n -w net.ipv4.ip_forward=0

#
# If net.ipv4.ip_forward present in /etc/sysctl.conf, change value to "0"
#	else, add "net.ipv4.ip_forward = 0" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.ip_forward /etc/sysctl.conf ; then
	sed -i 's/^net.ipv4.ip_forward.*/net.ipv4.ip_forward = 0/g' /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.ip_forward to 0 per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.ip_forward = 0" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0
net.ipv4.conf.all.accept_source_route = 0

sysctl_net_ipv4_conf_all_accept_source_route_value="0"

#
# Set runtime for net.ipv4.conf.all.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.accept_source_route=$sysctl_net_ipv4_conf_all_accept_source_route_value

#
# If net.ipv4.conf.all.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.all.accept_source_route = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.accept_source_route /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.conf.all.accept_source_route.*/net.ipv4.conf.all.accept_source_route = $sysctl_net_ipv4_conf_all_accept_source_route_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.conf.all.accept_source_route to $sysctl_net_ipv4_conf_all_accept_source_route_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.conf.all.accept_source_route = $sysctl_net_ipv4_conf_all_accept_source_route_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0
net.ipv4.conf.all.accept_redirects = 0

sysctl_net_ipv4_conf_all_accept_redirects_value="0"

#
# Set runtime for net.ipv4.conf.all.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.accept_redirects=$sysctl_net_ipv4_conf_all_accept_redirects_value

#
# If net.ipv4.conf.all.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.all.accept_redirects = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.accept_redirects /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.conf.all.accept_redirects.*/net.ipv4.conf.all.accept_redirects = $sysctl_net_ipv4_conf_all_accept_redirects_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.conf.all.accept_redirects to $sysctl_net_ipv4_conf_all_accept_redirects_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.conf.all.accept_redirects = $sysctl_net_ipv4_conf_all_accept_redirects_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.conf.all.secure_redirects=0
net.ipv4.conf.all.secure_redirects = 0

sysctl_net_ipv4_conf_all_secure_redirects_value="1"

#
# Set runtime for net.ipv4.conf.all.secure_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.secure_redirects=$sysctl_net_ipv4_conf_all_secure_redirects_value

#
# If net.ipv4.conf.all.secure_redirects present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.all.secure_redirects = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.secure_redirects /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.conf.all.secure_redirects.*/net.ipv4.conf.all.secure_redirects = $sysctl_net_ipv4_conf_all_secure_redirects_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.conf.all.secure_redirects to $sysctl_net_ipv4_conf_all_secure_redirects_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.conf.all.secure_redirects = $sysctl_net_ipv4_conf_all_secure_redirects_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.conf.all.log_martians=1
net.ipv4.conf.all.log_martians = 1

sysctl_net_ipv4_conf_all_log_martians_value="0"

#
# Set runtime for net.ipv4.conf.all.log_martians
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.log_martians=$sysctl_net_ipv4_conf_all_log_martians_value

#
# If net.ipv4.conf.all.log_martians present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.all.log_martians = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.log_martians /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.conf.all.log_martians.*/net.ipv4.conf.all.log_martians = $sysctl_net_ipv4_conf_all_log_martians_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.conf.all.log_martians to $sysctl_net_ipv4_conf_all_log_martians_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.conf.all.log_martians = $sysctl_net_ipv4_conf_all_log_martians_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.conf.default.accept_source_route=0
net.ipv4.conf.default.accept_source_route = 0

sysctl_net_ipv4_conf_default_accept_source_route_value="0"

#
# Set runtime for net.ipv4.conf.default.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.accept_source_route=$sysctl_net_ipv4_conf_default_accept_source_route_value

#
# If net.ipv4.conf.default.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.default.accept_source_route = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.default.accept_source_route /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.conf.default.accept_source_route.*/net.ipv4.conf.default.accept_source_route = $sysctl_net_ipv4_conf_default_accept_source_route_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.conf.default.accept_source_route to $sysctl_net_ipv4_conf_default_accept_source_route_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.conf.default.accept_source_route = $sysctl_net_ipv4_conf_default_accept_source_route_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0
net.ipv4.conf.default.accept_redirects = 0

sysctl_net_ipv4_conf_default_accept_redirects_value="0"

#
# Set runtime for net.ipv4.conf.default.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.accept_redirects=$sysctl_net_ipv4_conf_default_accept_redirects_value

#
# If net.ipv4.conf.default.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.default.accept_redirects = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.default.accept_redirects /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.conf.default.accept_redirects.*/net.ipv4.conf.default.accept_redirects = $sysctl_net_ipv4_conf_default_accept_redirects_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.conf.default.accept_redirects to $sysctl_net_ipv4_conf_default_accept_redirects_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.conf.default.accept_redirects = $sysctl_net_ipv4_conf_default_accept_redirects_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.conf.default.secure_redirects=0
net.ipv4.conf.default.secure_redirects = 0

sysctl_net_ipv4_conf_default_secure_redirects_value="1"

#
# Set runtime for net.ipv4.conf.default.secure_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.secure_redirects=$sysctl_net_ipv4_conf_default_secure_redirects_value

#
# If net.ipv4.conf.default.secure_redirects present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.default.secure_redirects = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.default.secure_redirects /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.conf.default.secure_redirects.*/net.ipv4.conf.default.secure_redirects = $sysctl_net_ipv4_conf_default_secure_redirects_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.conf.default.secure_redirects to $sysctl_net_ipv4_conf_default_secure_redirects_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.conf.default.secure_redirects = $sysctl_net_ipv4_conf_default_secure_redirects_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1
net.ipv4.icmp_echo_ignore_broadcasts = 1

sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value="1"

#
# Set runtime for net.ipv4.icmp_echo_ignore_broadcasts
#
/sbin/sysctl -q -n -w net.ipv4.icmp_echo_ignore_broadcasts=$sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value

#
# If net.ipv4.icmp_echo_ignore_broadcasts present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.icmp_echo_ignore_broadcasts = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.icmp_echo_ignore_broadcasts /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.icmp_echo_ignore_broadcasts.*/net.ipv4.icmp_echo_ignore_broadcasts = $sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.icmp_echo_ignore_broadcasts to $sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.icmp_echo_ignore_broadcasts = $sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1
net.ipv4.icmp_ignore_bogus_error_responses = 1

sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value="1"

#
# Set runtime for net.ipv4.icmp_ignore_bogus_error_responses
#
/sbin/sysctl -q -n -w net.ipv4.icmp_ignore_bogus_error_responses=$sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value

#
# If net.ipv4.icmp_ignore_bogus_error_responses present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.icmp_ignore_bogus_error_responses = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.icmp_ignore_bogus_error_responses /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.icmp_ignore_bogus_error_responses.*/net.ipv4.icmp_ignore_bogus_error_responses = $sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.icmp_ignore_bogus_error_responses to $sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.icmp_ignore_bogus_error_responses = $sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.tcp_syncookies=1
net.ipv4.tcp_syncookies = 1

sysctl_net_ipv4_tcp_syncookies_value="1"

#
# Set runtime for net.ipv4.tcp_syncookies
#
/sbin/sysctl -q -n -w net.ipv4.tcp_syncookies=$sysctl_net_ipv4_tcp_syncookies_value

#
# If net.ipv4.tcp_syncookies present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.tcp_syncookies = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.tcp_syncookies /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.tcp_syncookies.*/net.ipv4.tcp_syncookies = $sysctl_net_ipv4_tcp_syncookies_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.tcp_syncookies to $sysctl_net_ipv4_tcp_syncookies_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.tcp_syncookies = $sysctl_net_ipv4_tcp_syncookies_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.conf.all.rp_filter=1
net.ipv4.conf.all.rp_filter = 1

sysctl_net_ipv4_conf_all_rp_filter_value="1"

#
# Set runtime for net.ipv4.conf.all.rp_filter
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.rp_filter=$sysctl_net_ipv4_conf_all_rp_filter_value

#
# If net.ipv4.conf.all.rp_filter present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.all.rp_filter = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.all.rp_filter /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.conf.all.rp_filter.*/net.ipv4.conf.all.rp_filter = $sysctl_net_ipv4_conf_all_rp_filter_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.conf.all.rp_filter to $sysctl_net_ipv4_conf_all_rp_filter_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.conf.all.rp_filter = $sysctl_net_ipv4_conf_all_rp_filter_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv4.conf.default.rp_filter=1
net.ipv4.conf.default.rp_filter = 1

sysctl_net_ipv4_conf_default_rp_filter_value="1"

#
# Set runtime for net.ipv4.conf.default.rp_filter
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.rp_filter=$sysctl_net_ipv4_conf_default_rp_filter_value

#
# If net.ipv4.conf.default.rp_filter present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.default.rp_filter = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv4.conf.default.rp_filter /etc/sysctl.conf ; then
	sed -i "s/^net.ipv4.conf.default.rp_filter.*/net.ipv4.conf.default.rp_filter = $sysctl_net_ipv4_conf_default_rp_filter_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv4.conf.default.rp_filter to $sysctl_net_ipv4_conf_default_rp_filter_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv4.conf.default.rp_filter = $sysctl_net_ipv4_conf_default_rp_filter_value" >> /etc/sysctl.conf
fi

$ ifconfig -a
$ iwconfig
$ sudo ifdown interface
$ sudo rm /etc/sysconfig/network-scripts/ifcfg-interface
NETWORKING_IPV6=no
IPV6INIT=no
IPV6_AUTOCONF=no
$ sudo sysctl -w net.ipv6.conf.default.accept_ra=0
net.ipv6.conf.default.accept_ra = 0

sysctl_net_ipv6_conf_default_accept_ra_value="0"

#
# Set runtime for net.ipv6.conf.default.accept_ra
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_ra=$sysctl_net_ipv6_conf_default_accept_ra_value

#
# If net.ipv6.conf.default.accept_ra present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv6.conf.default.accept_ra = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv6.conf.default.accept_ra /etc/sysctl.conf ; then
	sed -i "s/^net.ipv6.conf.default.accept_ra.*/net.ipv6.conf.default.accept_ra = $sysctl_net_ipv6_conf_default_accept_ra_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv6.conf.default.accept_ra to $sysctl_net_ipv6_conf_default_accept_ra_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv6.conf.default.accept_ra = $sysctl_net_ipv6_conf_default_accept_ra_value" >> /etc/sysctl.conf
fi

$ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0
net.ipv6.conf.default.accept_redirects = 0

sysctl_net_ipv6_conf_default_accept_redirects_value="0"

#
# Set runtime for net.ipv6.conf.default.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_redirects=$sysctl_net_ipv6_conf_default_accept_redirects_value

#
# If net.ipv6.conf.default.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv6.conf.default.accept_redirects = value" to /etc/sysctl.conf
#
if grep --silent ^net.ipv6.conf.default.accept_redirects /etc/sysctl.conf ; then
	sed -i "s/^net.ipv6.conf.default.accept_redirects.*/net.ipv6.conf.default.accept_redirects = $sysctl_net_ipv6_conf_default_accept_redirects_value/g" /etc/sysctl.conf
else
	echo -e "\n# Set net.ipv6.conf.default.accept_redirects to $sysctl_net_ipv6_conf_default_accept_redirects_value per security requirements" >> /etc/sysctl.conf
	echo "net.ipv6.conf.default.accept_redirects = $sysctl_net_ipv6_conf_default_accept_redirects_value" >> /etc/sysctl.conf
fi

$ sudo iptables -nL --line-numbers
$ sudo service iptables restart
Chain INPUT (policy ACCEPT)
num  target     prot opt source       destination
1    ACCEPT     all  --  0.0.0.0/0    0.0.0.0/0    state RELATED,ESTABLISHED 
2    ACCEPT     icmp --  0.0.0.0/0    0.0.0.0/0
3    ACCEPT     all  --  0.0.0.0/0    0.0.0.0/0
4    ACCEPT     tcp  --  0.0.0.0/0    0.0.0.0/0    state NEW tcp dpt:22 
5    REJECT     all  --  0.0.0.0/0    0.0.0.0/0    reject-with icmp-host-prohibited 

Chain FORWARD (policy ACCEPT)
num  target     prot opt source       destination
1    REJECT     all  --  0.0.0.0/0    0.0.0.0/0    reject-with icmp-host-prohibited 

Chain OUTPUT (policy ACCEPT)
num  target     prot opt source       destination
$ sudo chkconfig --level 2345 ip6tables on
#
# Enable ip6tables for all run levels
#
/sbin/chkconfig --level 0123456 ip6tables on

#
# Start ip6tables if not currently running
#
/sbin/service ip6tables start

$ sudo chkconfig --level 2345 iptables on
#
# Enable iptables for all run levels
#
/sbin/chkconfig --level 0123456 iptables on

#
# Start iptables if not currently running
#
/sbin/service iptables start

install dccp /bin/true
echo "install dccp /bin/true" > /etc/modprobe.d/dccp.conf

install sctp /bin/true
echo "install sctp /bin/true" > /etc/modprobe.d/sctp.conf

install rds /bin/true
echo "install rds /bin/true" > /etc/modprobe.d/rds.conf

install tipc /bin/true
echo "install tipc /bin/true" > /etc/modprobe.d/tipc.conf

*.info;mail.none;authpriv.none;cron.none                /var/log/messages
authpriv.*                                              /var/log/secure
mail.*                                                  -/var/log/maillog
cron.*                                                  /var/log/cron
*.emerg                                                 *
uucp,news.crit                                          /var/log/spooler
local7.*                                                /var/log/boot.log
$ ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat
$ ls -l LOGFILE
$ sudo chmod 0600 LOGFILE

# List of log file paths to be inspected for correct permissions
# * Primarily inspect log file paths listed in /etc/rsyslog.conf
RSYSLOG_ETC_CONFIG="/etc/rsyslog.conf"
# * And also the log file paths listed after rsyslog's $IncludeConfig directive
#   (store the result into array for the case there's shell glob used as value of IncludeConfig)
RSYSLOG_INCLUDE_CONFIG=($(grep -e "\$IncludeConfig[[:space:]]\+[^[:space:];]\+" /etc/rsyslog.conf | cut -d ' ' -f 2))
# Declare an array to hold the final list of different log file paths
declare -a LOG_FILE_PATHS

# Browse each file selected above as containing paths of log files
# ('/etc/rsyslog.conf' and '/etc/rsyslog.d/*.conf' in the default configuration)
for LOG_FILE in "${RSYSLOG_ETC_CONFIG}" "${RSYSLOG_INCLUDE_CONFIG[@]}"
do
	# From each of these files extract just particular log file path(s), thus:
	# * Ignore lines starting with space (' '), comment ('#"), or variable syntax ('$') characters,
	# * Ignore empty lines,
	# * From the remaining valid rows select only fields constituting a log file path
	# Text file column is understood to represent a log file path if and only if all of the following are met:
	# * it contains at least one slash '/' character,
	# * it doesn't contain space (' '), colon (':'), and semicolon (';') characters
	# Search log file for path(s) only in case it exists!
	if [[ -f "${LOG_FILE}" ]]
	then
		MATCHED_ITEMS=$(sed -e "/^[[:space:]|#|$]/d ; s/[^\/]*[[:space:]]*\([^:;[:space:]]*\)/\1/g ; /^$/d" "${LOG_FILE}")
		# Since above sed command might return more than one item (delimited by newline), split the particular
		# matches entries into new array specific for this log file
		readarray -t ARRAY_FOR_LOG_FILE <<< "$MATCHED_ITEMS"
		# Concatenate the two arrays - previous content of $LOG_FILE_PATHS array with
		# items from newly created array for this log file
		LOG_FILE_PATHS=("${LOG_FILE_PATHS[@]}" "${ARRAY_FOR_LOG_FILE[@]}")
		# Delete the temporary array
		unset ARRAY_FOR_LOG_FILE
	fi
done

for PATH in "${LOG_FILE_PATHS[@]}"
do
	# Sanity check - if particular $PATH is empty string, skip it from further processing
	if [ -z "$PATH" ]
	then
		continue
	fi
	# Per https://access.redhat.com/solutions/66805 '/var/log/boot.log' log file needs special care => perform it
	if [ "$PATH" == "/var/log/boot.log" ]
	then
		# Ensure permissions of /var/log/boot.log are configured to be updated in /etc/rc.local
		if ! /bin/grep -q "boot.log" "/etc/rc.local"
		then
			echo "/bin/chmod 600 /var/log/boot.log" >> /etc/rc.local
		fi
		# Ensure /etc/rc.d/rc.local has user-executable permission
		# (in order to be actually executed during boot)
		if [ "$(/usr/bin/stat -c %a /etc/rc.d/rc.local)" -ne 744 ]
		then
			/bin/chmod u+x /etc/rc.d/rc.local
		fi
	fi
	# Also for each log file check if its permissions differ from 600. If so, correct them
	if [ "$(/usr/bin/stat -c %a "$PATH")" -ne 600 ]
	then
		/bin/chmod 600 "$PATH"
	fi
done

*.* @loghost.example.com
*.* @@loghost.example.com
*.* :omrelp:loghost.example.com
$ModLoad imtcp
$InputTCPServerRun port
$ModLoad imudp
$UDPServerRun port
$ModLoad imrelp
$InputRELPServerRun port
/var/log/messages /var/log/secure /var/log/maillog /var/log/spooler \
  /var/log/boot.log /var/log/cron {
# rotate log files frequency
daily
$ sudo yum install rsyslog
yum -y install rsyslog

$ sudo chkconfig --level 2345 rsyslog on
#
# Enable rsyslog for all run levels
#
/sbin/chkconfig --level 0123456 rsyslog on

#
# Start rsyslog if not currently running
#
/sbin/service rsyslog start

type=AVC msg=audit(1226874073.147:96): avc:  denied  { getattr } for pid=2465 comm="httpd"
path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0 
tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file

type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13 
a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48
gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd"
exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)

max_log_file = STOREMB

var_auditd_max_log_file="6"

AUDITCONFIG=/etc/audit/auditd.conf

grep -q ^max_log_file $AUDITCONFIG && \
  sed -i 's/^max_log_file.*/max_log_file = '"$var_auditd_max_log_file"'/g' $AUDITCONFIG
if ! [ $? -eq 0 ]; then
  echo "max_log_file = $var_auditd_max_log_file" >> $AUDITCONFIG
fi

max_log_file_action = ACTION

var_auditd_max_log_file_action="rotate"

AUDITCONFIG=/etc/audit/auditd.conf

grep -q ^max_log_file_action $AUDITCONFIG && \
  sed -i 's/^max_log_file_action.*/max_log_file_action = '"$var_auditd_max_log_file_action"'/g' $AUDITCONFIG
if ! [ $? -eq 0 ]; then
  echo "max_log_file_action = $var_auditd_max_log_file_action" >> $AUDITCONFIG
fi

space_left_action = ACTION

var_auditd_space_left_action="email"

#
# If space_left_action present in /etc/audit/auditd.conf, change value
# to var_auditd_space_left_action, else
# add "space_left_action = $var_auditd_space_left_action" to /etc/audit/auditd.conf
#

if grep --silent ^space_left_action /etc/audit/auditd.conf ; then
        sed -i 's/^space_left_action.*/space_left_action = '"$var_auditd_space_left_action"'/g' /etc/audit/auditd.conf
else
        echo -e "\n# Set space_left_action to $var_auditd_space_left_action per security requirements" >> /etc/audit/auditd.conf
        echo "space_left_action = $var_auditd_space_left_action" >> /etc/audit/auditd.conf
fi

admin_space_left_action = ACTION

var_auditd_admin_space_left_action="single"

grep -q ^admin_space_left_action /etc/audit/auditd.conf && \
  sed -i "s/admin_space_left_action.*/admin_space_left_action = $var_auditd_admin_space_left_action/g" /etc/audit/auditd.conf
if ! [ $? -eq 0 ]; then
    echo "admin_space_left_action = $var_auditd_admin_space_left_action" >> /etc/audit/auditd.conf
fi

action_mail_acct = root

var_auditd_action_mail_acct="root"

AUDITCONFIG=/etc/audit/auditd.conf

grep -q ^action_mail_acct $AUDITCONFIG && \
  sed -i 's/^action_mail_acct.*/action_mail_acct = '"$var_auditd_action_mail_acct"'/g' $AUDITCONFIG
if ! [ $? -eq 0 ]; then
  echo "action_mail_acct = $var_auditd_action_mail_acct" >> $AUDITCONFIG
fi

$ sudo service auditd restart
# audit_time_rules
-a always,exit -F arch=b32 -S adjtimex -k audit_time_rules
# audit_time_rules
-a always,exit -F arch=b64 -S adjtimex -k audit_time_rules
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
        echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
        # Extract audit $key from audit rule so we can use it later
        key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)')
        # Check if particular audit rule is already defined
        IFS=$'\n' matches=($(sed -s -n -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        for match in "${matches[@]}"
        do
                files_to_inspect=("${files_to_inspect[@]}" "${match}")
        done
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do

        # Filter existing $audit_file rules' definitions to select those that:
        # * follow the rule pattern, and
        # * meet the hardware architecture requirement, and
        # * are current syscall group specific
        IFS=$'\n' existing_rules=($(sed -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file"))
        # Reset IFS back to default
        unset $IFS

        # Process rules found case-by-case
        for rule in "${existing_rules[@]}"
        do
                # Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
                if [ "${rule}" != "${full_rule}" ]
                then
                        # If so, isolate just '(-S \w)+' substring of that rule
                        rule_syscalls=$(echo $rule | grep -o -P '(-S \w+ )+')
                        # Check if list of '-S syscall' arguments of that rule is subset
                        # of '-S syscall' list of expected $full_rule
                        if grep -q -- "$rule_syscalls" <<< "$full_rule"
                        then
                                # Rule is covered (i.e. the list of -S syscalls for this rule is
                                # subset of -S syscalls of $full_rule => existing rule can be deleted
                                # Thus delete the rule from audit.rules & our array
                                sed -i -e "/$rule/d" "$audit_file"
                                existing_rules=("${existing_rules[@]//$rule/}")
                        else
                                # Rule isn't covered by $full_rule - it besides -S syscall arguments
                                # for this group contains also -S syscall arguments for other syscall
                                # group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
                                # since 'lchown' & 'fchownat' share 'chown' substring
                                # Therefore:
                                # * 1) delete the original rule from audit.rules
                                # (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
                                # * 2) delete the -S syscall arguments for this syscall group, but
                                # keep those not belonging to this syscall group
                                # (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
                                # * 3) append the modified (filtered) rule again into audit.rules
                                # if the same rule not already present
                                #
                                # 1) Delete the original rule
                                sed -i -e "/$rule/d" "$audit_file"
                                # 2) Delete syscalls for this group, but keep those from other groups
                                # Convert current rule syscall's string into array splitting by '-S' delimiter
                                IFS=$'-S' read -a rule_syscalls_as_array <<< "$rule_syscalls"
                                # Reset IFS back to default
                                unset $IFS
                                # Declare new empty string to hold '-S syscall' arguments from other groups
                                new_syscalls_for_rule=''
                                # Walk through existing '-S syscall' arguments
                                for syscall_arg in "${rule_syscalls_as_array[@]}"
                                do
                                        # Skip empty $syscall_arg values
                                        if [ "$syscall_arg" == '' ]
                                        then
                                                continue
                                        fi
                                        # If the '-S syscall' doesn't belong to current group add it to the new list
                                        # (together with adding '-S' delimiter back for each of such item found)
                                        if grep -q -v -- "$group" <<< "$syscall_arg"
                                        then
                                                new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
                                        fi
                                done
                                # Replace original '-S syscall' list with the new one for this rule
                                updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
                                # Squeeze repeated whitespace characters in rule definition (if any) into one
                                updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
                                # 3) Append the modified / filtered rule again into audit.rules
                                #    (but only in case it's not present yet to prevent duplicate definitions)
                                if ! grep -q -- "$updated_rule" "$audit_file"
                                then
                                        echo "$updated_rule" >> "$audit_file"
                                fi
                        fi
                else
                        # $audit_file already contains the expected rule form for this
                        # architecture & key => don't insert it second time
                        append_expected_rule=1
                fi
        done

        # We deleted all rules that were subset of the expected one for this arch & key.
        # Also isolated rules containing system calls not from this system calls group.
        # Now append the expected rule if it's not present in $audit_file yet
        if [[ ${append_expected_rule} -eq "0" ]]
        then
                echo "$full_rule" >> "$audit_file"
        fi
done

}

function rhel6_perform_audit_adjtimex_settimeofday_stime_remediation {

# Perform the remediation for the 'adjtimex', 'settimeofday', and 'stime' audit
# system calls on Red Hat Enterprise Linux 6 OS
#
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
        PATTERN="-a always,exit -F arch=${ARCH} -S .* -k *"
        # Create expected audit group and audit rule form for particular system call & architecture
        if [ ${ARCH} = "b32" ]
        then
                # stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
                # so append it to the list of time group system calls to be audited
                GROUP="\(adjtimex\|settimeofday\|stime\)"
                FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -S stime -k audit_time_rules"
        elif [ ${ARCH} = "b64" ]
        then
                # stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
                # therefore don't add it to the list of time group system calls to be audited
                GROUP="\(adjtimex\|settimeofday\)"
                FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -k audit_time_rules"
        fi
        # Perform the remediation itself
        fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

}

rhel6_perform_audit_adjtimex_settimeofday_stime_remediation

# audit_time_rules
-a always,exit -F arch=b32 -S settimeofday -k audit_time_rules
# audit_time_rules
-a always,exit -F arch=b64 -S settimeofday -k audit_time_rules
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
        echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
        # Extract audit $key from audit rule so we can use it later
        key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)')
        # Check if particular audit rule is already defined
        IFS=$'\n' matches=($(sed -s -n -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        for match in "${matches[@]}"
        do
                files_to_inspect=("${files_to_inspect[@]}" "${match}")
        done
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do

        # Filter existing $audit_file rules' definitions to select those that:
        # * follow the rule pattern, and
        # * meet the hardware architecture requirement, and
        # * are current syscall group specific
        IFS=$'\n' existing_rules=($(sed -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file"))
        # Reset IFS back to default
        unset $IFS

        # Process rules found case-by-case
        for rule in "${existing_rules[@]}"
        do
                # Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
                if [ "${rule}" != "${full_rule}" ]
                then
                        # If so, isolate just '(-S \w)+' substring of that rule
                        rule_syscalls=$(echo $rule | grep -o -P '(-S \w+ )+')
                        # Check if list of '-S syscall' arguments of that rule is subset
                        # of '-S syscall' list of expected $full_rule
                        if grep -q -- "$rule_syscalls" <<< "$full_rule"
                        then
                                # Rule is covered (i.e. the list of -S syscalls for this rule is
                                # subset of -S syscalls of $full_rule => existing rule can be deleted
                                # Thus delete the rule from audit.rules & our array
                                sed -i -e "/$rule/d" "$audit_file"
                                existing_rules=("${existing_rules[@]//$rule/}")
                        else
                                # Rule isn't covered by $full_rule - it besides -S syscall arguments
                                # for this group contains also -S syscall arguments for other syscall
                                # group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
                                # since 'lchown' & 'fchownat' share 'chown' substring
                                # Therefore:
                                # * 1) delete the original rule from audit.rules
                                # (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
                                # * 2) delete the -S syscall arguments for this syscall group, but
                                # keep those not belonging to this syscall group
                                # (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
                                # * 3) append the modified (filtered) rule again into audit.rules
                                # if the same rule not already present
                                #
                                # 1) Delete the original rule
                                sed -i -e "/$rule/d" "$audit_file"
                                # 2) Delete syscalls for this group, but keep those from other groups
                                # Convert current rule syscall's string into array splitting by '-S' delimiter
                                IFS=$'-S' read -a rule_syscalls_as_array <<< "$rule_syscalls"
                                # Reset IFS back to default
                                unset $IFS
                                # Declare new empty string to hold '-S syscall' arguments from other groups
                                new_syscalls_for_rule=''
                                # Walk through existing '-S syscall' arguments
                                for syscall_arg in "${rule_syscalls_as_array[@]}"
                                do
                                        # Skip empty $syscall_arg values
                                        if [ "$syscall_arg" == '' ]
                                        then
                                                continue
                                        fi
                                        # If the '-S syscall' doesn't belong to current group add it to the new list
                                        # (together with adding '-S' delimiter back for each of such item found)
                                        if grep -q -v -- "$group" <<< "$syscall_arg"
                                        then
                                                new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
                                        fi
                                done
                                # Replace original '-S syscall' list with the new one for this rule
                                updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
                                # Squeeze repeated whitespace characters in rule definition (if any) into one
                                updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
                                # 3) Append the modified / filtered rule again into audit.rules
                                #    (but only in case it's not present yet to prevent duplicate definitions)
                                if ! grep -q -- "$updated_rule" "$audit_file"
                                then
                                        echo "$updated_rule" >> "$audit_file"
                                fi
                        fi
                else
                        # $audit_file already contains the expected rule form for this
                        # architecture & key => don't insert it second time
                        append_expected_rule=1
                fi
        done

        # We deleted all rules that were subset of the expected one for this arch & key.
        # Also isolated rules containing system calls not from this system calls group.
        # Now append the expected rule if it's not present in $audit_file yet
        if [[ ${append_expected_rule} -eq "0" ]]
        then
                echo "$full_rule" >> "$audit_file"
        fi
done

}

function rhel6_perform_audit_adjtimex_settimeofday_stime_remediation {

# Perform the remediation for the 'adjtimex', 'settimeofday', and 'stime' audit
# system calls on Red Hat Enterprise Linux 6 OS
#
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
        PATTERN="-a always,exit -F arch=${ARCH} -S .* -k *"
        # Create expected audit group and audit rule form for particular system call & architecture
        if [ ${ARCH} = "b32" ]
        then
                # stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
                # so append it to the list of time group system calls to be audited
                GROUP="\(adjtimex\|settimeofday\|stime\)"
                FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -S stime -k audit_time_rules"
        elif [ ${ARCH} = "b64" ]
        then
                # stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
                # therefore don't add it to the list of time group system calls to be audited
                GROUP="\(adjtimex\|settimeofday\)"
                FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -k audit_time_rules"
        fi
        # Perform the remediation itself
        fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

}

rhel6_perform_audit_adjtimex_settimeofday_stime_remediation

# audit_time_rules
-a always,exit -F arch=b32 -S stime -k audit_time_rules
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
        echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
        # Extract audit $key from audit rule so we can use it later
        key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)')
        # Check if particular audit rule is already defined
        IFS=$'\n' matches=($(sed -s -n -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        for match in "${matches[@]}"
        do
                files_to_inspect=("${files_to_inspect[@]}" "${match}")
        done
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do

        # Filter existing $audit_file rules' definitions to select those that:
        # * follow the rule pattern, and
        # * meet the hardware architecture requirement, and
        # * are current syscall group specific
        IFS=$'\n' existing_rules=($(sed -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file"))
        # Reset IFS back to default
        unset $IFS

        # Process rules found case-by-case
        for rule in "${existing_rules[@]}"
        do
                # Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
                if [ "${rule}" != "${full_rule}" ]
                then
                        # If so, isolate just '(-S \w)+' substring of that rule
                        rule_syscalls=$(echo $rule | grep -o -P '(-S \w+ )+')
                        # Check if list of '-S syscall' arguments of that rule is subset
                        # of '-S syscall' list of expected $full_rule
                        if grep -q -- "$rule_syscalls" <<< "$full_rule"
                        then
                                # Rule is covered (i.e. the list of -S syscalls for this rule is
                                # subset of -S syscalls of $full_rule => existing rule can be deleted
                                # Thus delete the rule from audit.rules & our array
                                sed -i -e "/$rule/d" "$audit_file"
                                existing_rules=("${existing_rules[@]//$rule/}")
                        else
                                # Rule isn't covered by $full_rule - it besides -S syscall arguments
                                # for this group contains also -S syscall arguments for other syscall
                                # group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
                                # since 'lchown' & 'fchownat' share 'chown' substring
                                # Therefore:
                                # * 1) delete the original rule from audit.rules
                                # (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
                                # * 2) delete the -S syscall arguments for this syscall group, but
                                # keep those not belonging to this syscall group
                                # (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
                                # * 3) append the modified (filtered) rule again into audit.rules
                                # if the same rule not already present
                                #
                                # 1) Delete the original rule
                                sed -i -e "/$rule/d" "$audit_file"
                                # 2) Delete syscalls for this group, but keep those from other groups
                                # Convert current rule syscall's string into array splitting by '-S' delimiter
                                IFS=$'-S' read -a rule_syscalls_as_array <<< "$rule_syscalls"
                                # Reset IFS back to default
                                unset $IFS
                                # Declare new empty string to hold '-S syscall' arguments from other groups
                                new_syscalls_for_rule=''
                                # Walk through existing '-S syscall' arguments
                                for syscall_arg in "${rule_syscalls_as_array[@]}"
                                do
                                        # Skip empty $syscall_arg values
                                        if [ "$syscall_arg" == '' ]
                                        then
                                                continue
                                        fi
                                        # If the '-S syscall' doesn't belong to current group add it to the new list
                                        # (together with adding '-S' delimiter back for each of such item found)
                                        if grep -q -v -- "$group" <<< "$syscall_arg"
                                        then
                                                new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
                                        fi
                                done
                                # Replace original '-S syscall' list with the new one for this rule
                                updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
                                # Squeeze repeated whitespace characters in rule definition (if any) into one
                                updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
                                # 3) Append the modified / filtered rule again into audit.rules
                                #    (but only in case it's not present yet to prevent duplicate definitions)
                                if ! grep -q -- "$updated_rule" "$audit_file"
                                then
                                        echo "$updated_rule" >> "$audit_file"
                                fi
                        fi
                else
                        # $audit_file already contains the expected rule form for this
                        # architecture & key => don't insert it second time
                        append_expected_rule=1
                fi
        done

        # We deleted all rules that were subset of the expected one for this arch & key.
        # Also isolated rules containing system calls not from this system calls group.
        # Now append the expected rule if it's not present in $audit_file yet
        if [[ ${append_expected_rule} -eq "0" ]]
        then
                echo "$full_rule" >> "$audit_file"
        fi
done

}

function rhel6_perform_audit_adjtimex_settimeofday_stime_remediation {

# Perform the remediation for the 'adjtimex', 'settimeofday', and 'stime' audit
# system calls on Red Hat Enterprise Linux 6 OS
#
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
        PATTERN="-a always,exit -F arch=${ARCH} -S .* -k *"
        # Create expected audit group and audit rule form for particular system call & architecture
        if [ ${ARCH} = "b32" ]
        then
                # stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
                # so append it to the list of time group system calls to be audited
                GROUP="\(adjtimex\|settimeofday\|stime\)"
                FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -S stime -k audit_time_rules"
        elif [ ${ARCH} = "b64" ]
        then
                # stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
                # therefore don't add it to the list of time group system calls to be audited
                GROUP="\(adjtimex\|settimeofday\)"
                FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -k audit_time_rules"
        fi
        # Perform the remediation itself
        fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

}

rhel6_perform_audit_adjtimex_settimeofday_stime_remediation

-w /etc/localtime -p wa -k audit_time_rules

# Perform the remediation

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"

# audit_rules_usergroup_modification
-w /etc/group -p wa -k audit_rules_usergroup_modification
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

# Perform the remediation

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/etc/group" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "auditctl" "/etc/passwd" "wa" "audit_rules_usergroup_modification"

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/etc/gshadow" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "auditctl" "/etc/shadow" "wa" "audit_rules_usergroup_modification"

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/etc/security/opasswd" "wa" "audit_rules_usergroup_modification"

# audit_rules_networkconfig_modification
-a always,exit -F arch=ARCH -S sethostname -S setdomainname -k audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S .* -k *"
	# Use escaped BRE regex to specify rule group
	GROUP="set\(host\|domain\)name"
	FULL_RULE="-a always,exit -F arch=$ARCH -S sethostname -S setdomainname -k audit_rules_networkconfig_modification"

function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
        echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
        # Extract audit $key from audit rule so we can use it later
        key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)')
        # Check if particular audit rule is already defined
        IFS=$'\n' matches=($(sed -s -n -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        for match in "${matches[@]}"
        do
                files_to_inspect=("${files_to_inspect[@]}" "${match}")
        done
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do

        # Filter existing $audit_file rules' definitions to select those that:
        # * follow the rule pattern, and
        # * meet the hardware architecture requirement, and
        # * are current syscall group specific
        IFS=$'\n' existing_rules=($(sed -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file"))
        # Reset IFS back to default
        unset $IFS

        # Process rules found case-by-case
        for rule in "${existing_rules[@]}"
        do
                # Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
                if [ "${rule}" != "${full_rule}" ]
                then
                        # If so, isolate just '(-S \w)+' substring of that rule
                        rule_syscalls=$(echo $rule | grep -o -P '(-S \w+ )+')
                        # Check if list of '-S syscall' arguments of that rule is subset
                        # of '-S syscall' list of expected $full_rule
                        if grep -q -- "$rule_syscalls" <<< "$full_rule"
                        then
                                # Rule is covered (i.e. the list of -S syscalls for this rule is
                                # subset of -S syscalls of $full_rule => existing rule can be deleted
                                # Thus delete the rule from audit.rules & our array
                                sed -i -e "/$rule/d" "$audit_file"
                                existing_rules=("${existing_rules[@]//$rule/}")
                        else
                                # Rule isn't covered by $full_rule - it besides -S syscall arguments
                                # for this group contains also -S syscall arguments for other syscall
                                # group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
                                # since 'lchown' & 'fchownat' share 'chown' substring
                                # Therefore:
                                # * 1) delete the original rule from audit.rules
                                # (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
                                # * 2) delete the -S syscall arguments for this syscall group, but
                                # keep those not belonging to this syscall group
                                # (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
                                # * 3) append the modified (filtered) rule again into audit.rules
                                # if the same rule not already present
                                #
                                # 1) Delete the original rule
                                sed -i -e "/$rule/d" "$audit_file"
                                # 2) Delete syscalls for this group, but keep those from other groups
                                # Convert current rule syscall's string into array splitting by '-S' delimiter
                                IFS=$'-S' read -a rule_syscalls_as_array <<< "$rule_syscalls"
                                # Reset IFS back to default
                                unset $IFS
                                # Declare new empty string to hold '-S syscall' arguments from other groups
                                new_syscalls_for_rule=''
                                # Walk through existing '-S syscall' arguments
                                for syscall_arg in "${rule_syscalls_as_array[@]}"
                                do
                                        # Skip empty $syscall_arg values
                                        if [ "$syscall_arg" == '' ]
                                        then
                                                continue
                                        fi
                                        # If the '-S syscall' doesn't belong to current group add it to the new list
                                        # (together with adding '-S' delimiter back for each of such item found)
                                        if grep -q -v -- "$group" <<< "$syscall_arg"
                                        then
                                                new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
                                        fi
                                done
                                # Replace original '-S syscall' list with the new one for this rule
                                updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
                                # Squeeze repeated whitespace characters in rule definition (if any) into one
                                updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
                                # 3) Append the modified / filtered rule again into audit.rules
                                #    (but only in case it's not present yet to prevent duplicate definitions)
                                if ! grep -q -- "$updated_rule" "$audit_file"
                                then
                                        echo "$updated_rule" >> "$audit_file"
                                fi
                        fi
                else
                        # $audit_file already contains the expected rule form for this
                        # architecture & key => don't insert it second time
                        append_expected_rule=1
                fi
        done

        # We deleted all rules that were subset of the expected one for this arch & key.
        # Also isolated rules containing system calls not from this system calls group.
        # Now append the expected rule if it's not present in $audit_file yet
        if [[ ${append_expected_rule} -eq "0" ]]
        then
                echo "$full_rule" >> "$audit_file"
        fi
done

}

	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

# Then perform the remediations for the watch rules

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/etc/issue" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "auditctl" "/etc/issue.net" "wa" "audit_rules_networkconfig_modification"

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/etc/hosts" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "auditctl" "/etc/sysconfig/network" "wa" "audit_rules_networkconfig_modification"

-w /etc/selinux/ -p wa -k MAC-policy

# Perform the remediation

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/etc/selinux/" "wa" "MAC-policy"

-w /var/log/tallylog -p wa -k logins
-w /var/run/faillock/ -p wa -k logins
-w /var/log/lastlog -p wa -k logins

# Perform the remediation

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/var/log/tallylog" "wa" "logins"
fix_audit_watch_rule "auditctl" "/var/run/faillock/" "wa" "logins"

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/var/log/lastlog" "wa" "logins"

-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session

# Perform the remediation

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/var/run/utmp" "wa" "session"
fix_audit_watch_rule "auditctl" "/var/log/btmp" "wa" "session"

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/var/log/wtmp" "wa" "session"

-a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

# Perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do

	# First fix the -EACCES requirement
	PATTERN="-a always,exit -F arch=$ARCH -S .* -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k *"
	# Use escaped BRE regex to specify rule group
	GROUP="\(creat\|open\|truncate\)"
	FULL_RULE="-a always,exit -F arch=$ARCH -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access"

function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
        echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
        # Extract audit $key from audit rule so we can use it later
        key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)')
        # Check if particular audit rule is already defined
        IFS=$'\n' matches=($(sed -s -n -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        for match in "${matches[@]}"
        do
                files_to_inspect=("${files_to_inspect[@]}" "${match}")
        done
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do

        # Filter existing $audit_file rules' definitions to select those that:
        # * follow the rule pattern, and
        # * meet the hardware architecture requirement, and
        # * are current syscall group specific
        IFS=$'\n' existing_rules=($(sed -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file"))
        # Reset IFS back to default
        unset $IFS

        # Process rules found case-by-case
        for rule in "${existing_rules[@]}"
        do
                # Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
                if [ "${rule}" != "${full_rule}" ]
                then
                        # If so, isolate just '(-S \w)+' substring of that rule
                        rule_syscalls=$(echo $rule | grep -o -P '(-S \w+ )+')
                        # Check if list of '-S syscall' arguments of that rule is subset
                        # of '-S syscall' list of expected $full_rule
                        if grep -q -- "$rule_syscalls" <<< "$full_rule"
                        then
                                # Rule is covered (i.e. the list of -S syscalls for this rule is
                                # subset of -S syscalls of $full_rule => existing rule can be deleted
                                # Thus delete the rule from audit.rules & our array
                                sed -i -e "/$rule/d" "$audit_file"
                                existing_rules=("${existing_rules[@]//$rule/}")
                        else
                                # Rule isn't covered by $full_rule - it besides -S syscall arguments
                                # for this group contains also -S syscall arguments for other syscall
                                # group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
                                # since 'lchown' & 'fchownat' share 'chown' substring
                                # Therefore:
                                # * 1) delete the original rule from audit.rules
                                # (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
                                # * 2) delete the -S syscall arguments for this syscall group, but
                                # keep those not belonging to this syscall group
                                # (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
                                # * 3) append the modified (filtered) rule again into audit.rules
                                # if the same rule not already present
                                #
                                # 1) Delete the original rule
                                sed -i -e "/$rule/d" "$audit_file"
                                # 2) Delete syscalls for this group, but keep those from other groups
                                # Convert current rule syscall's string into array splitting by '-S' delimiter
                                IFS=$'-S' read -a rule_syscalls_as_array <<< "$rule_syscalls"
                                # Reset IFS back to default
                                unset $IFS
                                # Declare new empty string to hold '-S syscall' arguments from other groups
                                new_syscalls_for_rule=''
                                # Walk through existing '-S syscall' arguments
                                for syscall_arg in "${rule_syscalls_as_array[@]}"
                                do
                                        # Skip empty $syscall_arg values
                                        if [ "$syscall_arg" == '' ]
                                        then
                                                continue
                                        fi
                                        # If the '-S syscall' doesn't belong to current group add it to the new list
                                        # (together with adding '-S' delimiter back for each of such item found)
                                        if grep -q -v -- "$group" <<< "$syscall_arg"
                                        then
                                                new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
                                        fi
                                done
                                # Replace original '-S syscall' list with the new one for this rule
                                updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
                                # Squeeze repeated whitespace characters in rule definition (if any) into one
                                updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
                                # 3) Append the modified / filtered rule again into audit.rules
                                #    (but only in case it's not present yet to prevent duplicate definitions)
                                if ! grep -q -- "$updated_rule" "$audit_file"
                                then
                                        echo "$updated_rule" >> "$audit_file"
                                fi
                        fi
                else
                        # $audit_file already contains the expected rule form for this
                        # architecture & key => don't insert it second time
                        append_expected_rule=1
                fi
        done

        # We deleted all rules that were subset of the expected one for this arch & key.
        # Also isolated rules containing system calls not from this system calls group.
        # Now append the expected rule if it's not present in $audit_file yet
        if [[ ${append_expected_rule} -eq "0" ]]
        then
                echo "$full_rule" >> "$audit_file"
        fi
done

}

	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"

	# Then fix the -EPERM requirement
	PATTERN="-a always,exit -F arch=$ARCH -S .* -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k *"
	# No need to change content of $GROUP variable - it's the same as for -EACCES case above
	FULL_RULE="-a always,exit -F arch=$ARCH -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access"

function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
        echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
        # Extract audit $key from audit rule so we can use it later
        key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)')
        # Check if particular audit rule is already defined
        IFS=$'\n' matches=($(sed -s -n -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        for match in "${matches[@]}"
        do
                files_to_inspect=("${files_to_inspect[@]}" "${match}")
        done
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do

        # Filter existing $audit_file rules' definitions to select those that:
        # * follow the rule pattern, and
        # * meet the hardware architecture requirement, and
        # * are current syscall group specific
        IFS=$'\n' existing_rules=($(sed -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file"))
        # Reset IFS back to default
        unset $IFS

        # Process rules found case-by-case
        for rule in "${existing_rules[@]}"
        do
                # Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
                if [ "${rule}" != "${full_rule}" ]
                then
                        # If so, isolate just '(-S \w)+' substring of that rule
                        rule_syscalls=$(echo $rule | grep -o -P '(-S \w+ )+')
                        # Check if list of '-S syscall' arguments of that rule is subset
                        # of '-S syscall' list of expected $full_rule
                        if grep -q -- "$rule_syscalls" <<< "$full_rule"
                        then
                                # Rule is covered (i.e. the list of -S syscalls for this rule is
                                # subset of -S syscalls of $full_rule => existing rule can be deleted
                                # Thus delete the rule from audit.rules & our array
                                sed -i -e "/$rule/d" "$audit_file"
                                existing_rules=("${existing_rules[@]//$rule/}")
                        else
                                # Rule isn't covered by $full_rule - it besides -S syscall arguments
                                # for this group contains also -S syscall arguments for other syscall
                                # group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
                                # since 'lchown' & 'fchownat' share 'chown' substring
                                # Therefore:
                                # * 1) delete the original rule from audit.rules
                                # (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
                                # * 2) delete the -S syscall arguments for this syscall group, but
                                # keep those not belonging to this syscall group
                                # (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
                                # * 3) append the modified (filtered) rule again into audit.rules
                                # if the same rule not already present
                                #
                                # 1) Delete the original rule
                                sed -i -e "/$rule/d" "$audit_file"
                                # 2) Delete syscalls for this group, but keep those from other groups
                                # Convert current rule syscall's string into array splitting by '-S' delimiter
                                IFS=$'-S' read -a rule_syscalls_as_array <<< "$rule_syscalls"
                                # Reset IFS back to default
                                unset $IFS
                                # Declare new empty string to hold '-S syscall' arguments from other groups
                                new_syscalls_for_rule=''
                                # Walk through existing '-S syscall' arguments
                                for syscall_arg in "${rule_syscalls_as_array[@]}"
                                do
                                        # Skip empty $syscall_arg values
                                        if [ "$syscall_arg" == '' ]
                                        then
                                                continue
                                        fi
                                        # If the '-S syscall' doesn't belong to current group add it to the new list
                                        # (together with adding '-S' delimiter back for each of such item found)
                                        if grep -q -v -- "$group" <<< "$syscall_arg"
                                        then
                                                new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
                                        fi
                                done
                                # Replace original '-S syscall' list with the new one for this rule
                                updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
                                # Squeeze repeated whitespace characters in rule definition (if any) into one
                                updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
                                # 3) Append the modified / filtered rule again into audit.rules
                                #    (but only in case it's not present yet to prevent duplicate definitions)
                                if ! grep -q -- "$updated_rule" "$audit_file"
                                then
                                        echo "$updated_rule" >> "$audit_file"
                                fi
                        fi
                else
                        # $audit_file already contains the expected rule form for this
                        # architecture & key => don't insert it second time
                        append_expected_rule=1
                fi
        done

        # We deleted all rules that were subset of the expected one for this arch & key.
        # Also isolated rules containing system calls not from this system calls group.
        # Now append the expected rule if it's not present in $audit_file yet
        if [[ ${append_expected_rule} -eq "0" ]]
        then
                echo "$full_rule" >> "$audit_file"
        fi
done

}

	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"

done

$ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null
-a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

# Perform the remediation

function perform_audit_rules_privileged_commands_remediation {
#
# Load function arguments into local variables
local tool="$1"
local min_auid="$2"

# Check sanity of the input
if [ $# -ne "2" ]
then
        echo "Usage: perform_audit_rules_privileged_commands_remediation 'auditctl | augenrules' '500 | 1000'"
        echo "Aborting."
        exit 1
fi

declare -a files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then:
# * add '/etc/audit/audit.rules'to the list of files to be inspected,
# * specify '/etc/audit/audit.rules' as the output audit file, where
#   missing rules should be inserted
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("/etc/audit/audit.rules")
        output_audit_file="/etc/audit/audit.rules"
#
# If the audit tool is 'augenrules', then:
# * add '/etc/audit/rules.d/*.rules' to the list of files to be inspected
#   (split by newline),
# * specify /etc/audit/rules.d/privileged.rules' as the output file, where
#   missing rules should be inserted
elif [ "$tool" == 'augenrules' ]
then
        IFS=$'\n' files_to_inspect=($(find /etc/audit/rules.d -maxdepth 1 -type f -name *.rules -print))
        output_audit_file="/etc/audit/rules.d/privileged.rules"
fi

# Obtain the list of SUID/SGID binaries on the particular system (split by newline)
# into privileged_binaries array
IFS=$'\n' privileged_binaries=($(find / -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null))

# Keep list of SUID/SGID binaries that have been already handled within some previous iteration
declare -a sbinaries_to_skip=()

# For each found sbinary in privileged_binaries list
for sbinary in "${privileged_binaries[@]}"
do

        # Replace possible slash '/' character in sbinary definition so we could use it in sed expressions below
        sbinary_esc=${sbinary//$'/'/$'\/'}
        # Check if this sbinary wasn't already handled in some of the previous iterations
        # Return match only if whole sbinary definition matched (not in the case just prefix matched!!!)
        if [[ $(sed -ne "/${sbinary_esc}$/p" <<< ${sbinaries_to_skip[@]}) ]]
        then
                # If so, don't process it second time & go to process next sbinary
                continue
        fi

        # Reset the counter of inspected files when starting to check
        # presence of existing audit rule for new sbinary
        local count_of_inspected_files=0

        # For each audit rules file from the list of files to be inspected
        for afile in "${files_to_inspect[@]}"
        do

                # Search current audit rules file's content for match. Match criteria:
                # * existing rule is for the same SUID/SGID binary we are currently processing (but
                #   can contain multiple -F path= elements covering multiple SUID/SGID binaries)
                # * existing rule contains all arguments from expected rule form (though can contain
                #   them in arbitrary order)

                base_search=$(sed -e "/-a always,exit/!d" -e "/-F path=${sbinary_esc}$/!d"   \
                                  -e "/-F path=[^[:space:]]\+/!d" -e "/-F perm=.*/!d"       \
                                  -e "/-F auid>=${min_auid}/!d" -e "/-F auid!=4294967295/!d"  \
                                  -e "/-k privileged/!d" $afile)

                # Increase the count of inspected files for this sbinary
                count_of_inspected_files=$((count_of_inspected_files + 1))

                # Define expected rule form for this binary
                expected_rule="-a always,exit -F path=${sbinary} -F perm=x -F auid>=${min_auid} -F auid!=4294967295 -k privileged"

                # Require execute access type to be set for existing audit rule
                exec_access='x'

                # Search current audit rules file's content for presence of rule pattern for this sbinary
                if [[ $base_search ]]
                then

                        # Current audit rules file already contains rule for this binary =>
                        # Store the exact form of found rule for this binary for further processing
                        concrete_rule=$base_search

                        # Select all other SUID/SGID binaries possibly also present in the found rule
                        IFS=$'\n' handled_sbinaries=($(grep -o -e "-F path=[^[:space:]]\+" <<< $concrete_rule))
                        IFS=$' ' handled_sbinaries=(${handled_sbinaries[@]//-F path=/})

                        # Merge the list of such SUID/SGID binaries found in this iteration with global list ignoring duplicates
                        sbinaries_to_skip=($(for i in "${sbinaries_to_skip[@]}" "${handled_sbinaries[@]}"; do echo $i; done | sort -du))

                        # Separate concrete_rule into three sections using hash '#'
                        # sign as a delimiter around rule's permission section borders
                        concrete_rule=$(echo $concrete_rule | sed -n "s/\(.*\)\+\(-F perm=[rwax]\+\)\+/\1#\2#/p")

                        # Split concrete_rule into head, perm, and tail sections using hash '#' delimiter
                        IFS=$'#' read rule_head rule_perm rule_tail <<<  "$concrete_rule"

                        # Extract already present exact access type [r|w|x|a] from rule's permission section
                        access_type=${rule_perm//-F perm=/}

                        # Verify current permission access type(s) for rule contain 'x' (execute) permission
                        if ! grep -q "$exec_access" <<< "$access_type"
                        then

                                # If not, append the 'x' (execute) permission to the existing access type bits
                                access_type="$access_type$exec_access"
                                # Reconstruct the permissions section for the rule
                                new_rule_perm="-F perm=$access_type"
                                # Update existing rule in current audit rules file with the new permission section
                                sed -i "s#${rule_head}\(.*\)${rule_tail}#${rule_head}${new_rule_perm}${rule_tail}#" $afile

                        fi

                # If the required audit rule for particular sbinary wasn't found yet, insert it under following conditions:
                #
                # * in the "auditctl" mode of operation insert particular rule each time
                #   (because in this mode there's only one file -- /etc/audit/audit.rules to be inspected for presence of this rule),
                #
                # * in the "augenrules" mode of operation insert particular rule only once and only in case we have already
                #   searched all of the files from /etc/audit/rules.d/*.rules location (since that audit rule can be defined
                #   in any of those files and if not, we want it to be inserted only once into /etc/audit/rules.d/privileged.rules file)
                #
                elif [ "$tool" == "auditctl" ] || [[ "$tool" == "augenrules" && $count_of_inspected_files -eq "${#files_to_inspect[@]}" ]]
                then

                        # Current audit rules file's content doesn't contain expected rule for this
                        # SUID/SGID binary yet => append it
                        echo $expected_rule >> $output_audit_file
                fi

        done

done

}

perform_audit_rules_privileged_commands_remediation "auditctl" "500"

-a always,exit -F arch=ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export

# Perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=500 -F auid!=4294967295 -k *"
	GROUP="mount"
	FULL_RULE="-a always,exit -F arch=$ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export"

function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
        echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
        # Extract audit $key from audit rule so we can use it later
        key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)')
        # Check if particular audit rule is already defined
        IFS=$'\n' matches=($(sed -s -n -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        for match in "${matches[@]}"
        do
                files_to_inspect=("${files_to_inspect[@]}" "${match}")
        done
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do

        # Filter existing $audit_file rules' definitions to select those that:
        # * follow the rule pattern, and
        # * meet the hardware architecture requirement, and
        # * are current syscall group specific
        IFS=$'\n' existing_rules=($(sed -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file"))
        # Reset IFS back to default
        unset $IFS

        # Process rules found case-by-case
        for rule in "${existing_rules[@]}"
        do
                # Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
                if [ "${rule}" != "${full_rule}" ]
                then
                        # If so, isolate just '(-S \w)+' substring of that rule
                        rule_syscalls=$(echo $rule | grep -o -P '(-S \w+ )+')
                        # Check if list of '-S syscall' arguments of that rule is subset
                        # of '-S syscall' list of expected $full_rule
                        if grep -q -- "$rule_syscalls" <<< "$full_rule"
                        then
                                # Rule is covered (i.e. the list of -S syscalls for this rule is
                                # subset of -S syscalls of $full_rule => existing rule can be deleted
                                # Thus delete the rule from audit.rules & our array
                                sed -i -e "/$rule/d" "$audit_file"
                                existing_rules=("${existing_rules[@]//$rule/}")
                        else
                                # Rule isn't covered by $full_rule - it besides -S syscall arguments
                                # for this group contains also -S syscall arguments for other syscall
                                # group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
                                # since 'lchown' & 'fchownat' share 'chown' substring
                                # Therefore:
                                # * 1) delete the original rule from audit.rules
                                # (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
                                # * 2) delete the -S syscall arguments for this syscall group, but
                                # keep those not belonging to this syscall group
                                # (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
                                # * 3) append the modified (filtered) rule again into audit.rules
                                # if the same rule not already present
                                #
                                # 1) Delete the original rule
                                sed -i -e "/$rule/d" "$audit_file"
                                # 2) Delete syscalls for this group, but keep those from other groups
                                # Convert current rule syscall's string into array splitting by '-S' delimiter
                                IFS=$'-S' read -a rule_syscalls_as_array <<< "$rule_syscalls"
                                # Reset IFS back to default
                                unset $IFS
                                # Declare new empty string to hold '-S syscall' arguments from other groups
                                new_syscalls_for_rule=''
                                # Walk through existing '-S syscall' arguments
                                for syscall_arg in "${rule_syscalls_as_array[@]}"
                                do
                                        # Skip empty $syscall_arg values
                                        if [ "$syscall_arg" == '' ]
                                        then
                                                continue
                                        fi
                                        # If the '-S syscall' doesn't belong to current group add it to the new list
                                        # (together with adding '-S' delimiter back for each of such item found)
                                        if grep -q -v -- "$group" <<< "$syscall_arg"
                                        then
                                                new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
                                        fi
                                done
                                # Replace original '-S syscall' list with the new one for this rule
                                updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
                                # Squeeze repeated whitespace characters in rule definition (if any) into one
                                updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
                                # 3) Append the modified / filtered rule again into audit.rules
                                #    (but only in case it's not present yet to prevent duplicate definitions)
                                if ! grep -q -- "$updated_rule" "$audit_file"
                                then
                                        echo "$updated_rule" >> "$audit_file"
                                fi
                        fi
                else
                        # $audit_file already contains the expected rule form for this
                        # architecture & key => don't insert it second time
                        append_expected_rule=1
                fi
        done

        # We deleted all rules that were subset of the expected one for this arch & key.
        # Also isolated rules containing system calls not from this system calls group.
        # Now append the expected rule if it's not present in $audit_file yet
        if [[ ${append_expected_rule} -eq "0" ]]
        then
                echo "$full_rule" >> "$audit_file"
        fi
done

}

	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

-a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete

# Perform the remediation for the syscall rule
# Retrieve hardware architecture of the underlying system
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in ${RULE_ARCHS[@]}
do
	PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=500 -F auid!=4294967295 -k delete"
	# Use escaped BRE regex to specify rule group
	GROUP="\(rmdir\|unlink\|rename\)"
	FULL_RULE="-a always,exit -F arch=$ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete"

function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
        echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
        # Extract audit $key from audit rule so we can use it later
        key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)')
        # Check if particular audit rule is already defined
        IFS=$'\n' matches=($(sed -s -n -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        for match in "${matches[@]}"
        do
                files_to_inspect=("${files_to_inspect[@]}" "${match}")
        done
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do

        # Filter existing $audit_file rules' definitions to select those that:
        # * follow the rule pattern, and
        # * meet the hardware architecture requirement, and
        # * are current syscall group specific
        IFS=$'\n' existing_rules=($(sed -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file"))
        # Reset IFS back to default
        unset $IFS

        # Process rules found case-by-case
        for rule in "${existing_rules[@]}"
        do
                # Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
                if [ "${rule}" != "${full_rule}" ]
                then
                        # If so, isolate just '(-S \w)+' substring of that rule
                        rule_syscalls=$(echo $rule | grep -o -P '(-S \w+ )+')
                        # Check if list of '-S syscall' arguments of that rule is subset
                        # of '-S syscall' list of expected $full_rule
                        if grep -q -- "$rule_syscalls" <<< "$full_rule"
                        then
                                # Rule is covered (i.e. the list of -S syscalls for this rule is
                                # subset of -S syscalls of $full_rule => existing rule can be deleted
                                # Thus delete the rule from audit.rules & our array
                                sed -i -e "/$rule/d" "$audit_file"
                                existing_rules=("${existing_rules[@]//$rule/}")
                        else
                                # Rule isn't covered by $full_rule - it besides -S syscall arguments
                                # for this group contains also -S syscall arguments for other syscall
                                # group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
                                # since 'lchown' & 'fchownat' share 'chown' substring
                                # Therefore:
                                # * 1) delete the original rule from audit.rules
                                # (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
                                # * 2) delete the -S syscall arguments for this syscall group, but
                                # keep those not belonging to this syscall group
                                # (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
                                # * 3) append the modified (filtered) rule again into audit.rules
                                # if the same rule not already present
                                #
                                # 1) Delete the original rule
                                sed -i -e "/$rule/d" "$audit_file"
                                # 2) Delete syscalls for this group, but keep those from other groups
                                # Convert current rule syscall's string into array splitting by '-S' delimiter
                                IFS=$'-S' read -a rule_syscalls_as_array <<< "$rule_syscalls"
                                # Reset IFS back to default
                                unset $IFS
                                # Declare new empty string to hold '-S syscall' arguments from other groups
                                new_syscalls_for_rule=''
                                # Walk through existing '-S syscall' arguments
                                for syscall_arg in "${rule_syscalls_as_array[@]}"
                                do
                                        # Skip empty $syscall_arg values
                                        if [ "$syscall_arg" == '' ]
                                        then
                                                continue
                                        fi
                                        # If the '-S syscall' doesn't belong to current group add it to the new list
                                        # (together with adding '-S' delimiter back for each of such item found)
                                        if grep -q -v -- "$group" <<< "$syscall_arg"
                                        then
                                                new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
                                        fi
                                done
                                # Replace original '-S syscall' list with the new one for this rule
                                updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
                                # Squeeze repeated whitespace characters in rule definition (if any) into one
                                updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
                                # 3) Append the modified / filtered rule again into audit.rules
                                #    (but only in case it's not present yet to prevent duplicate definitions)
                                if ! grep -q -- "$updated_rule" "$audit_file"
                                then
                                        echo "$updated_rule" >> "$audit_file"
                                fi
                        fi
                else
                        # $audit_file already contains the expected rule form for this
                        # architecture & key => don't insert it second time
                        append_expected_rule=1
                fi
        done

        # We deleted all rules that were subset of the expected one for this arch & key.
        # Also isolated rules containing system calls not from this system calls group.
        # Now append the expected rule if it's not present in $audit_file yet
        if [[ ${append_expected_rule} -eq "0" ]]
        then
                echo "$full_rule" >> "$audit_file"
        fi
done

}

	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

-w /etc/sudoers -p wa -k actions

# Perform the remediation

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/etc/sudoers" "wa" "actions"

-w /sbin/insmod -p x -k modules
-w /sbin/rmmod -p x -k modules
-w /sbin/modprobe -p x -k modules
-a always,exit -F arch=ARCH -S init_module -S delete_module -k modules

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit kernel modules can't be loaded / unloaded on 64-bit kernel =>
#       it's not required on a 64-bit system to check also for the presence
#       of 32-bit's equivalent of the corresponding rule. Therefore for
#       each system it's enought to check presence of system's native rule form.
[ $(getconf LONG_BIT) = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S .* -k *"
	# Use escaped BRE regex to specify rule group
	GROUP="\(init\|delete\)_module"
	FULL_RULE="-a always,exit -F arch=$ARCH -S init_module -S delete_module -k modules"

function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
        echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
        # Extract audit $key from audit rule so we can use it later
        key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)')
        # Check if particular audit rule is already defined
        IFS=$'\n' matches=($(sed -s -n -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        for match in "${matches[@]}"
        do
                files_to_inspect=("${files_to_inspect[@]}" "${match}")
        done
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do

        # Filter existing $audit_file rules' definitions to select those that:
        # * follow the rule pattern, and
        # * meet the hardware architecture requirement, and
        # * are current syscall group specific
        IFS=$'\n' existing_rules=($(sed -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file"))
        # Reset IFS back to default
        unset $IFS

        # Process rules found case-by-case
        for rule in "${existing_rules[@]}"
        do
                # Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
                if [ "${rule}" != "${full_rule}" ]
                then
                        # If so, isolate just '(-S \w)+' substring of that rule
                        rule_syscalls=$(echo $rule | grep -o -P '(-S \w+ )+')
                        # Check if list of '-S syscall' arguments of that rule is subset
                        # of '-S syscall' list of expected $full_rule
                        if grep -q -- "$rule_syscalls" <<< "$full_rule"
                        then
                                # Rule is covered (i.e. the list of -S syscalls for this rule is
                                # subset of -S syscalls of $full_rule => existing rule can be deleted
                                # Thus delete the rule from audit.rules & our array
                                sed -i -e "/$rule/d" "$audit_file"
                                existing_rules=("${existing_rules[@]//$rule/}")
                        else
                                # Rule isn't covered by $full_rule - it besides -S syscall arguments
                                # for this group contains also -S syscall arguments for other syscall
                                # group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
                                # since 'lchown' & 'fchownat' share 'chown' substring
                                # Therefore:
                                # * 1) delete the original rule from audit.rules
                                # (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
                                # * 2) delete the -S syscall arguments for this syscall group, but
                                # keep those not belonging to this syscall group
                                # (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
                                # * 3) append the modified (filtered) rule again into audit.rules
                                # if the same rule not already present
                                #
                                # 1) Delete the original rule
                                sed -i -e "/$rule/d" "$audit_file"
                                # 2) Delete syscalls for this group, but keep those from other groups
                                # Convert current rule syscall's string into array splitting by '-S' delimiter
                                IFS=$'-S' read -a rule_syscalls_as_array <<< "$rule_syscalls"
                                # Reset IFS back to default
                                unset $IFS
                                # Declare new empty string to hold '-S syscall' arguments from other groups
                                new_syscalls_for_rule=''
                                # Walk through existing '-S syscall' arguments
                                for syscall_arg in "${rule_syscalls_as_array[@]}"
                                do
                                        # Skip empty $syscall_arg values
                                        if [ "$syscall_arg" == '' ]
                                        then
                                                continue
                                        fi
                                        # If the '-S syscall' doesn't belong to current group add it to the new list
                                        # (together with adding '-S' delimiter back for each of such item found)
                                        if grep -q -v -- "$group" <<< "$syscall_arg"
                                        then
                                                new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
                                        fi
                                done
                                # Replace original '-S syscall' list with the new one for this rule
                                updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
                                # Squeeze repeated whitespace characters in rule definition (if any) into one
                                updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
                                # 3) Append the modified / filtered rule again into audit.rules
                                #    (but only in case it's not present yet to prevent duplicate definitions)
                                if ! grep -q -- "$updated_rule" "$audit_file"
                                then
                                        echo "$updated_rule" >> "$audit_file"
                                fi
                        fi
                else
                        # $audit_file already contains the expected rule form for this
                        # architecture & key => don't insert it second time
                        append_expected_rule=1
                fi
        done

        # We deleted all rules that were subset of the expected one for this arch & key.
        # Also isolated rules containing system calls not from this system calls group.
        # Now append the expected rule if it's not present in $audit_file yet
        if [[ ${append_expected_rule} -eq "0" ]]
        then
                echo "$full_rule" >> "$audit_file"
        fi
done

}

	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

# Then perform the remediations for the watch rules

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/sbin/insmod" "x" "modules"
fix_audit_watch_rule "auditctl" "/sbin/rmmod" "x" "modules"

function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
        echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#       auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#       augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#       augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
        # Case when particular audit rule is already defined in some of /etc/audit/rules.d/*.rules file
        # Get pair -- filepath : matching_row into @matches array
        IFS=$'\n' matches=($(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        # For each of the matched entries
        for match in "${matches[@]}"
        do
                # Extract filepath from the match
                rulesd_audit_file=$(echo $match | cut -f1 -d ':')
                # Append that path into list of files for inspection
                files_to_inspect=("${files_to_inspect[@]}" "$rulesd_audit_file")
        done
        # Case when particular audit rule isn't defined yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                # Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                # If the $key.rules file doesn't exist yet, create it with correct permissions
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
        then
                # Rule is found => verify yet if existing rule definition contains
                # all of the required access type bits

                # Escape slashes in path for use in sed pattern below
                local esc_path=${path//$'/'/$'\/'}
                # Define BRE whitespace class shortcut
                local sp="[[:space:]]"
                # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
                current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
                # Split required access bits string into characters array
                # (to check bit's presence for one bit at a time)
                for access_bit in $(echo "$required_access_bits" | grep -o .)
                do
                        # For each from the required access bits (e.g. 'w', 'a') check
                        # if they are already present in current access bits for rule.
                        # If not, append that bit at the end
                        if ! grep -q "$access_bit" <<< "$current_access_bits"
                        then
                                # Concatenate the existing mask with the missing bit
                                current_access_bits="$current_access_bits$access_bit"
                        fi
                done
                # Propagate the updated rule's access bits (original + the required
                # ones) back into the /etc/audit/audit.rules file for that rule
                sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
        else
                # Rule isn't present yet. Append it at the end of $audit_rules_file file
                # with proper key

                echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
        fi
done
}

fix_audit_watch_rule "auditctl" "/sbin/modprobe" "x" "modules"

-e 2

readonly AUDIT_RULES='/etc/audit/audit.rules'

# If '-e .*' setting present in audit.rules already, delete it since the
# auditctl(8) manual page instructs it should be the last rule in configuration
sed -i '/-e[[:space:]]\+.*/d' $AUDIT_RULES

# Append '-e 2' requirement at the end of audit.rules
echo '' >> $AUDIT_RULES
echo '# Set the audit.rules configuration immutable per security requirements' >> $AUDIT_RULES
echo '# Reboot is required to change audit rules once this setting is applied' >> $AUDIT_RULES
echo '-e 2' >> $AUDIT_RULES

$ sudo chkconfig --level 2345 auditd on

function service_command {

# Load function arguments into local variables
local service_state=$1
local service=$2
local xinetd=$(echo $3 | cut -d'=' -f2)

# Check sanity of the input
if [ $# -lt "2" ]
then
  echo "Usage: service_command 'enable/disable' 'service_name.service'"
  echo
  echo "To enable or disable xinetd services add \'xinetd=service_name\'"
  echo "as the last argument"
  echo "Aborting."
  exit 1
fi

# If systemctl is installed, use systemctl command; otherwise, use the service/chkconfig commands
if [ -f "/usr/bin/systemctl" ] ; then
  service_util="/usr/bin/systemctl"
else
  service_util="/sbin/service"
  chkconfig_util="/sbin/chkconfig"
fi

# If disable is not specified in arg1, set variables to enable services.
# Otherwise, variables are to be set to disable services.
if [ "$service_state" != 'disable' ] ; then
  service_state="enable"
  service_operation="start"
  chkconfig_state="on"
else
  service_state="disable"
  service_operation="stop"
  chkconfig_state="off"
fi

# If chkconfig_util is not empty, use chkconfig/service commands.
if ! [ "x$chkconfig_util" = x ] ; then
  $service_util $service $service_operation
  $chkconfig_util --level 0123456 $service $chkconfig_state
else
  $service_util $service_operation $service
  $service_util $service_state $service
fi

# Test if local variable xinetd is empty using non-bashism.
# If empty, then xinetd is not being used.
if ! [ "x$xinetd" = x ] ; then
  grep -qi disable /etc/xinetd.d/$xinetd && \

  if ! [ "$service_operation" != 'disable' ] ; then
    sed -i "s/disable.*/disable         = no/gI" /etc/xinetd.d/$xinetd
  else
    sed -i "s/disable.*/disable         = yes/gI" /etc/xinetd.d/$xinetd
  fi
fi

}

service_command enable auditd

kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet audit=1
/sbin/grubby --update-kernel=ALL --args="audit=1"

$ sudo yum erase xinetd
if rpm -qa | grep -q xinetd; then
	yum -y remove xinetd
fi

$ sudo yum erase telnet-server
if rpm -qa | grep -q telnet-server; then
	yum -y remove telnet-server
fi

$ sudo yum erase rsh-server
# CAUTION: This remediation script will remove rsh-server
#	   from the system, and may remove any packages
#	   that depend on rsh-server. Execute this
#	   remediation AFTER testing on a non-production
#	   system!
yum -y erase rsh-server

# CAUTION: This remediation script will remove rsh
#	   from the system, and may remove any packages
#	   that depend on rsh. Execute this
#	   remediation AFTER testing on a non-production
#	   system!
yum -y erase rsh

$ sudo rm /etc/hosts.equiv
$ rm ~/.rhosts
find -type f -name .rhosts -exec rm -f '{}' \;
rm /etc/hosts.equiv

$ sudo yum erase ypserv

function package_command {

# Load function arguments into local variables
local package_operation=$1
local package=$2

# Check sanity of the input
if [ $# -ne "2" ]
then
  echo "Usage: package_command 'install/uninstall' 'rpm_package_name"
  echo "Aborting."
  exit 1
fi

# If dnf is installed, use dnf; otherwise, use yum
if [ -f "/usr/bin/dnf" ] ; then
  install_util="/usr/bin/dnf"
else
  install_util="/usr/bin/yum"
fi

if [ "$package_operation" != 'remove' ] ; then
  # If the rpm is not installed, install the rpm
  if ! /bin/rpm -q --quiet $package; then
    $install_util -y $package_operation $package
  fi
else
  # If the rpm is installed, uninstall the rpm
  if /bin/rpm -q --quiet $package; then
    $install_util -y $package_operation $package
  fi
fi

}

package_command remove ypserv

# CAUTION: This remediation script will remove ypbind
#	   from the system, and may remove any packages
#	   that depend on ypbind. Execute this
#	   remediation AFTER testing on a non-production
#	   system!
yum -y erase ypbind

$ sudo yum erase tftp-server
$ sudo yum erase talk-server
# CAUTION: This remediation script will remove talk-server
#	   from the system, and may remove any packages
#	   that depend on talk-server. Execute this
#	   remediation AFTER testing on a non-production
#	   system!
yum -y erase talk-server

# CAUTION: This remediation script will remove talk
#	   from the system, and may remove any packages
#	   that depend on talk. Execute this
#	   remediation AFTER testing on a non-production
#	   system!
yum -y erase talk

$ sudo chkconfig rhnsd off
#
# Disable rhnsd for all run levels
#
/sbin/chkconfig --level 0123456 rhnsd off

#
# Stop rhnsd if currently running
#
/sbin/service rhnsd stop

$ sudo chkconfig --level 2345 crond on
#
# Enable crond for all run levels
#
/sbin/chkconfig --level 0123456 crond on

#
# Start crond if not currently running
#
/sbin/service crond start

$ sudo chkconfig atd off
#
# Disable atd for all run levels
#
/sbin/chkconfig --level 0123456 atd off

#
# Stop atd if currently running
#
/sbin/service atd stop

Protocol 2
grep -qi ^Protocol /etc/ssh/sshd_config && \
  sed -i "s/Protocol.*/Protocol 2/gI" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
    echo "Protocol 2" >> /etc/ssh/sshd_config
fi

DenyUsers USER1 USER2
ClientAliveInterval 300

sshd_idle_timeout_value="300"

grep -q ^ClientAliveInterval /etc/ssh/sshd_config && \
  sed -i "s/ClientAliveInterval.*/ClientAliveInterval $sshd_idle_timeout_value/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
    echo "ClientAliveInterval $sshd_idle_timeout_value" >> /etc/ssh/sshd_config
fi

IgnoreRhosts yes
grep -qi ^IgnoreRhosts /etc/ssh/sshd_config && \
  sed -i "s/IgnoreRhosts.*/IgnoreRhosts yes/gI" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
    echo "IgnoreRhosts yes" >> /etc/ssh/sshd_config
fi

HostbasedAuthentication no
grep -q ^HostbasedAuthentication /etc/ssh/sshd_config && \
  sed -i "s/HostbasedAuthentication.*/HostbasedAuthentication no/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
    echo "HostbasedAuthentication no" >> /etc/ssh/sshd_config
fi

PermitRootLogin no

SSHD_CONFIG='/etc/ssh/sshd_config'

# Obtain line number of first uncommented case-insensitive occurrence of Match
# block directive (possibly prefixed with whitespace) present in $SSHD_CONFIG
FIRST_MATCH_BLOCK=$(sed -n '/^[[:space:]]*Match[^\n]*/I{=;q}' $SSHD_CONFIG)

# Obtain line number of first uncommented case-insensitive occurence of
# PermitRootLogin directive (possibly prefixed with whitespace) present in
# $SSHD_CONFIG
FIRST_PERMIT_ROOT_LOGIN=$(sed -n '/^[[:space:]]*PermitRootLogin[^\n]*/I{=;q}' $SSHD_CONFIG)

# Case: Match block directive not present in $SSHD_CONFIG
if [ -z "$FIRST_MATCH_BLOCK" ]
then

    # Case: PermitRootLogin directive not present in $SSHD_CONFIG yet
    if [ -z "$FIRST_PERMIT_ROOT_LOGIN" ]
    then
        # Append 'PermitRootLogin no' at the end of $SSHD_CONFIG
        echo -e "\nPermitRootLogin no" >> $SSHD_CONFIG

    # Case: PermitRootLogin directive present in $SSHD_CONFIG already
    else
        # Replace first uncommented case-insensitive occurrence
        # of PermitRootLogin directive
        sed -i "$FIRST_PERMIT_ROOT_LOGIN s/^[[:space:]]*PermitRootLogin.*$/PermitRootLogin no/I" $SSHD_CONFIG
    fi

# Case: Match block directive present in $SSHD_CONFIG
else

    # Case: PermitRootLogin directive not present in $SSHD_CONFIG yet
    if [ -z "$FIRST_PERMIT_ROOT_LOGIN" ]
    then
        # Prepend 'PermitRootLogin no' before first uncommented
        # case-insensitive occurrence of Match block directive
        sed -i "$FIRST_MATCH_BLOCK s/^\([[:space:]]*Match[^\n]*\)/PermitRootLogin no\n\1/I" $SSHD_CONFIG

    # Case: PermitRootLogin directive present in $SSHD_CONFIG and placed
    #       before first Match block directive
    elif [ "$FIRST_PERMIT_ROOT_LOGIN" -lt "$FIRST_MATCH_BLOCK" ]
    then
        # Replace first uncommented case-insensitive occurrence
        # of PermitRootLogin directive
        sed -i "$FIRST_PERMIT_ROOT_LOGIN s/^[[:space:]]*PermitRootLogin.*$/PermitRootLogin no/I" $SSHD_CONFIG

    # Case: PermitRootLogin directive present in $SSHD_CONFIG and placed
    # after first Match block directive
    else
         # Prepend 'PermitRootLogin no' before first uncommented
         # case-insensitive occurrence of Match block directive
         sed -i "$FIRST_MATCH_BLOCK s/^\([[:space:]]*Match[^\n]*\)/PermitRootLogin no\n\1/I" $SSHD_CONFIG
    fi
fi

PermitEmptyPasswords no
grep -q ^PermitEmptyPasswords /etc/ssh/sshd_config && \
  sed -i "s/PermitEmptyPasswords.*/PermitEmptyPasswords no/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
    echo "PermitEmptyPasswords no" >> /etc/ssh/sshd_config
fi

Banner /etc/issue
grep -q ^Banner /etc/ssh/sshd_config && \
  sed -i "s/Banner.*/Banner \/etc\/issue/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
    echo "Banner /etc/issue" >> /etc/ssh/sshd_config
fi

Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
grep -q ^Ciphers /etc/ssh/sshd_config && \
  sed -i "s/Ciphers.*/Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc/g" /etc/ssh/sshd_config
if ! [ $? -eq 0 ]; then
    echo "Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc" >> /etc/ssh/sshd_config
fi

$ sudo yum groupremove "X Window System"
$ sudo chkconfig avahi-daemon off
#
# Disable avahi-daemon for all run levels
#
/sbin/chkconfig --level 0123456 avahi-daemon off

#
# Stop avahi-daemon if currently running
#
/sbin/service avahi-daemon stop

$ sudo chkconfig cups off
#
# Disable cups for all run levels
#
/sbin/chkconfig --level 0123456 cups off

#
# Stop cups if currently running
#
/sbin/service cups stop

$ sudo yum erase dhcp
$ sudo chkconfig --level 2345 ntpd on
#
# Enable ntpd for all run levels
#
/sbin/chkconfig --level 0123456 ntpd on

#
# Start ntpd if not currently running
#
/sbin/service ntpd start

server ntpserver
server ntpserver
inet_interfaces = localhost
$ sudo yum erase openldap-servers
$ sudo chkconfig nfslock off
#
# Disable nfslock for all run levels
#
/sbin/chkconfig --level 0123456 nfslock off

#
# Stop nfslock if currently running
#
/sbin/service nfslock stop

$ sudo chkconfig rpcgssd off
#
# Disable rpcgssd for all run levels
#
/sbin/chkconfig --level 0123456 rpcgssd off

#
# Stop rpcgssd if currently running
#
/sbin/service rpcgssd stop

$ sudo chkconfig rpcidmapd off
#
# Disable rpcidmapd for all run levels
#
/sbin/chkconfig --level 0123456 rpcidmapd off

#
# Stop rpcidmapd if currently running
#
/sbin/service rpcidmapd stop

$ sudo chkconfig rpcbind off

function service_command {

# Load function arguments into local variables
local service_state=$1
local service=$2
local xinetd=$(echo $3 | cut -d'=' -f2)

# Check sanity of the input
if [ $# -lt "2" ]
then
  echo "Usage: service_command 'enable/disable' 'service_name.service'"
  echo
  echo "To enable or disable xinetd services add \'xinetd=service_name\'"
  echo "as the last argument"
  echo "Aborting."
  exit 1
fi

# If systemctl is installed, use systemctl command; otherwise, use the service/chkconfig commands
if [ -f "/usr/bin/systemctl" ] ; then
  service_util="/usr/bin/systemctl"
else
  service_util="/sbin/service"
  chkconfig_util="/sbin/chkconfig"
fi

# If disable is not specified in arg1, set variables to enable services.
# Otherwise, variables are to be set to disable services.
if [ "$service_state" != 'disable' ] ; then
  service_state="enable"
  service_operation="start"
  chkconfig_state="on"
else
  service_state="disable"
  service_operation="stop"
  chkconfig_state="off"
fi

# If chkconfig_util is not empty, use chkconfig/service commands.
if ! [ "x$chkconfig_util" = x ] ; then
  $service_util $service $service_operation
  $chkconfig_util --level 0123456 $service $chkconfig_state
else
  $service_util $service_operation $service
  $service_util $service_state $service
fi

# Test if local variable xinetd is empty using non-bashism.
# If empty, then xinetd is not being used.
if ! [ "x$xinetd" = x ] ; then
  grep -qi disable /etc/xinetd.d/$xinetd && \

  if ! [ "$service_operation" != 'disable' ] ; then
    sed -i "s/disable.*/disable         = no/gI" /etc/xinetd.d/$xinetd
  else
    sed -i "s/disable.*/disable         = yes/gI" /etc/xinetd.d/$xinetd
  fi
fi

}

service_command disable rpcbind

$ sudo chkconfig rpcsvcgssd off
#
# Disable rpcsvcgssd for all run levels
#
/sbin/chkconfig --level 0123456 rpcsvcgssd off

#
# Stop rpcsvcgssd if currently running
#
/sbin/service rpcsvcgssd stop

$ sudo yum erase bind
$ sudo yum erase vsftpd
$ sudo yum erase httpd
# CAUTION: This remediation script will remove httpd
#	   from the system, and may remove any packages
#	   that depend on httpd. Execute this
#	   remediation AFTER testing on a non-production
#	   system!
yum -y erase httpd

$ sudo yum erase dovecot
# CAUTION: This remediation script will remove dovecot
#	   from the system, and may remove any packages
#	   that depend on dovecot. Execute this
#	   remediation AFTER testing on a non-production
#	   system!
yum -y erase dovecot

$ sudo yum erase samba

function package_command {

# Load function arguments into local variables
local package_operation=$1
local package=$2

# Check sanity of the input
if [ $# -ne "2" ]
then
  echo "Usage: package_command 'install/uninstall' 'rpm_package_name"
  echo "Aborting."
  exit 1
fi

# If dnf is installed, use dnf; otherwise, use yum
if [ -f "/usr/bin/dnf" ] ; then
  install_util="/usr/bin/dnf"
else
  install_util="/usr/bin/yum"
fi

if [ "$package_operation" != 'remove' ] ; then
  # If the rpm is not installed, install the rpm
  if ! /bin/rpm -q --quiet $package; then
    $install_util -y $package_operation $package
  fi
else
  # If the rpm is installed, uninstall the rpm
  if /bin/rpm -q --quiet $package; then
    $install_util -y $package_operation $package
  fi
fi

}

package_command remove samba

$ sudo yum erase squid
$ sudo yum erase net-snmp
# CAUTION: This remediation script will remove net-snmp
#	   from the system, and may remove any packages
#	   that depend on net-snmp. Execute this
#	   remediation AFTER testing on a non-production
#	   system!
yum -y erase net-snmp

Profile Title	C2S for Red Hat Enterprise Linux 6
Profile ID	xccdf_org.ssgproject.content_profile_C2S

Guide to the Secure Configuration of Red Hat Enterprise Linux 6

Revision History

Platforms

Table of Contents

Checklist

System Settingsgroup

Installing and Maintaining Softwaregroup

Disk Partitioninggroup

Ensure /tmp Located On Separate Partitionrule

Ensure /var Located On Separate Partitionrule

Ensure /var/log Located On Separate Partitionrule

Ensure /var/log/audit Located On Separate Partitionrule

Ensure /home Located On Separate Partitionrule

Updating Softwaregroup

Ensure Red Hat GPG Key Installedrule

Ensure gpgcheck Enabled In Main Yum Configurationrule

Ensure gpgcheck Enabled For All Yum Package Repositoriesrule

Software Integrity Checkinggroup

Verify Integrity with AIDEgroup

Install AIDErule

Build and Test AIDE Databaserule

Configure Periodic Execution of AIDErule

Verify Integrity with RPMgroup

Verify and Correct File Permissions with RPMrule

Verify File Hashes with RPMrule

Disable Prelinkingrule

File Permissions and Masksgroup

Restrict Partition Mount Optionsgroup

Add nodev Option to Non-Root Local Partitionsrule

Add nodev Option to Removable Media Partitionsrule

Add noexec Option to Removable Media Partitionsrule

Add nosuid Option to Removable Media Partitionsrule

Add nodev Option to /tmprule

Add noexec Option to /tmprule

Add nosuid Option to /tmprule

Add nodev Option to /dev/shmrule

Add noexec Option to /dev/shmrule

Add nosuid Option to /dev/shmrule

Bind Mount /var/tmp To /tmprule

Restrict Dynamic Mounting and Unmounting of Filesystemsgroup

Disable Mounting of cramfsrule

Disable Mounting of freevxfsrule

Disable Mounting of jffs2rule

Disable Mounting of hfsrule

Disable Mounting of hfsplusrule

Disable Mounting of squashfsrule

Disable Mounting of udfrule

Verify Permissions on Important Files and Directoriesgroup

Verify Permissions on Files with Local Account Information and Credentialsgroup

Verify User Who Owns shadow Filerule

Verify Group Who Owns shadow Filerule

Verify Permissions on shadow Filerule

Verify User Who Owns group Filerule

Verify Group Who Owns group Filerule

Verify Permissions on group Filerule

Verify User Who Owns gshadow Filerule

Verify Group Who Owns gshadow Filerule

Verify Permissions on gshadow Filerule

Verify User Who Owns passwd Filerule

Verify Group Who Owns passwd Filerule

Verify Permissions on passwd Filerule

Verify File Permissions Within Some Important Directoriesgroup

Verify that System Executables Have Restrictive Permissionsrule

Verify that All World-Writable Directories Have Sticky Bits Setrule

Ensure No World-Writable Files Existrule

Ensure All SGID Executables Are Authorizedrule

Ensure All SUID Executables Are Authorizedrule

Ensure All Files Are Owned by a Userrule

Ensure All Files Are Owned by a Grouprule

Restrict Programs from Dangerous Execution Patternsgroup

Daemon Umaskgroup

Set Daemon Umaskrule

Disable Core Dumpsgroup

Disable Core Dumps for All Usersrule

Disable Core Dumps for SUID programsrule

Enable ExecShieldgroup

Enable ExecShieldrule

Enable Randomized Layout of Virtual Address Spacerule

SELinuxgroup

Ensure SELinux Not Disabled in /etc/grub.confrule