Guide to the Secure Configuration of Red Hat Enterprise Linux 7

with profile Pre-release Draft STIG for RHEL 7 Server

This guide presents a catalog of security-relevant configuration settings for Red Hat Enterprise Linux 7 formatted in the eXtensible Configuration Checklist Description Format (XCCDF).

Providing system administrators with such guidance informs them how to securely configure systems under their control in a variety of network roles. Policy makers and baseline creators can use this catalog of settings, with its associated references to higher-level security control catalogs, in order to assist them in security baseline creation. This guide is a catalog, not a checklist, and satisfaction of every item is not likely to be possible or sensible in many operational scenarios. However, the XCCDF format enables granular selection and adjustment of settings, and their association with OVAL and OCIL content provides an automated checking capability. Transformations of this document, and its associated automated checking content, are capable of providing baselines that meet a diverse set of policy objectives. Some example XCCDF Profiles, which are selections of items that form checklists and can be used as baselines, are available with this guide. They can be processed, in an automated fashion, with tools that support the Security Content Automation Protocol (SCAP). The DISA STIG for RHEL 7 is one example of a baseline created from this guidance.
Do not attempt to implement any of the settings in this guide without first testing them in a non-operational environment. The creators of this guidance assume no responsibility whatsoever for its use by other parties, and makes no guarantees, expressed or implied, about its quality, reliability, or any other characteristic.
Profile TitlePre-release Draft STIG for RHEL 7 Server
Profile IDxccdf_org.ssgproject.content_profile_stig-rhel7-server-upstream

Revision History

Current version: 0.9

  • draft (as of 2015-07-30)

Platforms

  • cpe:/o:redhat:enterprise_linux:7
  • cpe:/o:redhat:enterprise_linux:7::client

Table of Contents

  1. System Settings
    1. Installing and Maintaining Software
    2. File Permissions and Masks
    3. Account and Access Control
    4. Configure Syslog
    5. System Accounting with auditd
  2. Services
    1. Base Services
    2. Cron and At Daemons
    3. SSH Server
    4. FTP Server

Checklist

contains 60 rules

System Settingsgroup

contains 52 rules

Installing and Maintaining Softwaregroup

The following sections contain information on security-relevant choices during the initial operating system installation process and the setup of software updates.

contains 7 rules

Disk Partitioninggroup

To ensure separation and protection of data, there are top-level system directories which should be placed on their own physical partition or logical volume. The installer's default partitioning scheme creates separate logical volumes for /, /boot, and swap.

  • If starting with any of the default layouts, check the box to "Review and modify partitioning." This allows for the easy creation of additional logical volumes inside the volume group already created, though it may require making /'s logical volume smaller to create space. In general, using logical volumes is preferable to using partitions because they can be more easily adjusted later.
  • If creating a custom layout, create the partitions mentioned in the previous paragraph (which the installer will require anyway), as well as separate ones described in the following sections.
If a system has already been installed, and the default partitioning scheme was used, it is possible but nontrivial to modify it to create separate logical volumes for the directories listed above. The Logical Volume Manager (LVM) makes this possible. See the LVM HOWTO at http://tldp.org/HOWTO/LVM-HOWTO/ for more detailed information on LVM.

contains 3 rules

Ensure /var/log Located On Separate Partitionrule

System logs are stored in the /var/log directory. Ensure that it has its own partition or logical volume at installation time, or migrate it using LVM.

Rationale:

Placing /var/log in its own partition enables better separation between log files and other files in /var/.

identifiers:  CCE-26967-0

references:  AU-9, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Test attestation on 20120928 by MM

Ensure /var/log/audit Located On Separate Partitionrule

Audit logs are stored in the /var/log/audit directory. Ensure that it has its own partition or logical volume at installation time, or migrate it later using LVM. Make absolutely certain that it is large enough to store all audit logs that will be created by the auditing daemon.

Rationale:

Placing /var/log/audit in its own partition enables better separation between audit files and other files, and helps ensure that auditing cannot be halted due to the partition running out of space.

identifiers:  CCE-26971-2

references:  AU-4, AU-9, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Test attestation on 20120928 by MM

Encrypt Partitionsrule

Red Hat Enterprise Linux 7 natively supports partition encryption through the Linux Unified Key Setup-on-disk-format (LUKS) technology. The easiest way to encrypt a partition is during installation time.

For manual installations, select the Encrypt checkbox during partition creation to encrypt the partition. When this option is selected the system will prompt for a passphrase to use in decrypting the partition. The passphrase will subsequently need to be entered manually every time the system boots.

For automated/unattended installations, it is possible to use Kickstart by adding the --encrypted and --passphrase= options to the definition of each partition to be encrypted. For example, the following line would encrypt the root partition: 

part / --fstype=ext4 --size=100 --onpart=hda1 --encrypted --passphrase=PASSPHRASE
Any PASSPHRASE is stored in the Kickstart in plaintext, and the Kickstart must then be protected accordingly. Omitting the --passphrase= option from the partition definition will cause the installer to pause and interactively ask for the passphrase during installation.

Detailed information on encrypting partitions using LUKS can be found on the Red Hat Documentation web site:
https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/7/html/Security_Guide/sec-Encryption.html

Rationale:

The risk of a system's physical compromise, particularly mobile systems such as laptops, places its data at risk of compromise. Encrypting this data mitigates the risk of its loss if the system is lost.

identifiers:  CCE-27128-8

references:  SC-13, SC-28, 1019, 1199, 1200, 185

Updating Softwaregroup

The yum command line tool is used to install and update software packages. The system also provides a graphical software update tool in the System menu, in the Administration submenu, called Software Update.

Red Hat Enterprise Linux systems contain an installed software catalog called the RPM database, which records metadata of installed packages. Consistently using yum or the graphical Software Update for all software installation allows for insight into the current inventory of installed software on the system.

contains 4 rules

Ensure Red Hat GPG Key Installedrule

To ensure the system can cryptographically verify base software packages come from Red Hat (and to connect to the Red Hat Network to receive them), the Red Hat GPG key must properly be installed. To install the Red Hat GPG key, run: 

$ sudo rhn_register
If the system is not connected to the Internet or an RHN Satellite, then install the Red Hat GPG key from trusted media such as the Red Hat installation CD-ROM or DVD. Assuming the disc is mounted in /media/cdrom, use the following command as the root user to import it into the keyring: 
$ sudo rpm --import /media/cdrom/RPM-GPG-KEY

Rationale:

Changes to software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor. The Red Hat GPG key is necessary to cryptographically verify packages are from Red Hat.

identifiers:  CCE-26957-1

references:  CM-5(3), SI-7, MA-1(b), 1749, 366, Test attestation on 20150407 by sdw

Remediation script:
# 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

Ensure gpgcheck Enabled In Main Yum Configurationrule

The gpgcheck option controls whether RPM packages' signatures are always checked prior to installation. To configure yum to check package signatures before installing them, ensure the following line appears in /etc/yum.conf in the [main] section: 

gpgcheck=1

Rationale:

Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This ensures the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. Certificates used to verify the software must be from an approved Certificate Authority (CA).

identifiers:  CCE-26989-4

references:  CM-5(3), SI-7, MA-1(b), 1749, 366, Test attestation on 20150407 by sdw

Ensure gpgcheck Enabled For All Yum Package Repositoriesrule

To ensure signature checking is not disabled for any repos, remove any lines from files in /etc/yum.repos.d of the form: 

gpgcheck=0

Rationale:

Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This ensures the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. Certificates used to verify the software must be from an approved Certificate Authority (CA).

identifiers:  CCE-26876-3

references:  CM-5(3), SI-7, MA-1(b), 1749, 366, Test attestation on 20150407 by sdw

Ensure Software Patches Installedrule

If the system is joined to the Red Hat Network, a Red Hat Satellite Server, or a yum server, run the following command to install updates: 

$ sudo yum update
If the system is not configured to use one of these sources, updates (in the form of RPM packages) can be manually downloaded from the Red Hat Network and installed using rpm.

Rationale:

Installing software updates is a fundamental mitigation against the exploitation of publicly-known vulnerabilities.

identifiers:  CCE-26853-2

references:  SI-2, MA-1(b), http://iase.disa.mil/stigs/cci/Pages/index.aspx, Test attestation on 20120928 by MM

File Permissions and Masksgroup

Traditional Unix security relies heavily on file and directory permissions to prevent unauthorized users from reading or modifying files to which they should not have access.

Several of the commands in this section search filesystems for files or directories with certain characteristics, and are intended to be run on every local partition on a given system. When the variable PART appears in one of the commands below, it means that the command is intended to be run repeatedly, with the name of each local partition substituted for PART in turn.

The following command prints a list of all xfs partitions on the local system, which is the default filesystem for Red Hat Enterprise Linux 7 installations: 

$ mount -t xfs | awk '{print $3}'
For any systems that use a different local filesystem type, modify this command as appropriate.

contains 1 rule

Restrict Dynamic Mounting and Unmounting of Filesystemsgroup

Linux includes a number of facilities for the automated addition and removal of filesystems on a running system. These facilities may be necessary in many environments, but this capability also carries some risk -- whether direct risk from allowing users to introduce arbitrary filesystems, or risk that software flaws in the automated mount facility itself could allow an attacker to compromise the system.

This command can be used to list the types of filesystems that are available to the currently executing kernel: 

$ find /lib/modules/`uname -r`/kernel/fs -type f -name '*.ko'
If these filesystems are not required then they can be explicitly disabled in a configuratio file in /etc/modprobe.d.

contains 1 rule

Disable the Automounterrule

The autofs daemon mounts and unmounts filesystems, such as user home directories shared via NFS, on demand. In addition, autofs can be used to handle removable media, and the default configuration provides the cdrom device as /misc/cd. However, this method of providing access to removable media is not common, so autofs can almost always be disabled if NFS is not in use. Even if NFS is required, it may be possible to configure filesystem mounts statically by editing /etc/fstab rather than relying on the automounter.

The autofs service can be disabled with the following command: 

$ sudo systemctl disable autofs

Rationale:

Disabling the automounter permits the administrator to statically control filesystem mounting through /etc/fstab.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-19(a), AC-19(d), AC-19(e), 1250, 85

Remediation script:
#
# Disable autofs.service for all systemd targets
#
systemctl disable autofs.service

#
# Stop autofs.service if currently running
#
systemctl stop autofs.service

Account and Access Controlgroup

In traditional Unix security, if an attacker gains shell access to a certain login account, they can perform any action or access any file to which that account has access. Therefore, making it more difficult for unauthorized people to gain shell access to accounts, particularly to privileged accounts, is a necessary part of securing a system. This section introduces mechanisms for restricting access to accounts under RHEL 7.

contains 15 rules

Protect Accounts by Restricting Password-Based Logingroup

Conventionally, Unix shell accounts are accessed by providing a username and password to a login program, which tests these values for correctness using the /etc/passwd and /etc/shadow files. Password-based login is vulnerable to guessing of weak passwords, and to sniffing and man-in-the-middle attacks against passwords entered over a network or at an insecure console. Therefore, mechanisms for accessing accounts by entering usernames and passwords should be restricted to those which are operationally necessary.

contains 3 rules

Set Password Expiration Parametersgroup

The file /etc/login.defs controls several password-related settings. Programs such as passwd, su, and login consult /etc/login.defs to determine behavior with regard to password aging, expiration warnings, and length. See the man page login.defs(5) for more information.

Users should be forced to change their passwords, in order to decrease the utility of compromised passwords. However, the need to change passwords often should be balanced against the risk that users will reuse or write down passwords if forced to change them too often. Forcing password changes every 90-360 days, depending on the environment, is recommended. Set the appropriate value as PASS_MAX_DAYS and apply it to existing accounts with the -M flag.

The PASS_MIN_DAYS (-m) setting prevents password changes for 7 days after the first change, to discourage password cycling. If you use this setting, train users to contact an administrator for an emergency password change in case a new password becomes compromised. The PASS_WARN_AGE (-W) setting gives users 7 days of warnings at login time that their passwords are about to expire.

For example, for each existing human user USER, expiration parameters could be adjusted to a 180 day maximum password age, 7 day minimum password age, and 7 day warning period with the following command: 

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

contains 2 rules
contains 1 rule

Protect Accounts by Configuring PAMgroup

PAM, or Pluggable Authentication Modules, is a system which implements modular authentication for Linux programs. PAM provides a flexible and configurable architecture for authentication, and it should be configured to minimize exposure to unnecessary risk. This section contains guidance on how to accomplish that.

PAM is implemented as a set of shared objects which are loaded and invoked whenever an application wishes to authenticate a user. Typically, the application must be running as root in order to take advantage of PAM, because PAM's modules often need to be able to access sensitive stores of account information, such as /etc/shadow. Traditional privileged network listeners (e.g. sshd) or SUID programs (e.g. sudo) already meet this requirement. An SUID root application, userhelper, is provided so that programs which are not SUID or privileged themselves can still take advantage of PAM.

PAM looks in the directory /etc/pam.d for application-specific configuration information. For instance, if the program login attempts to authenticate a user, then PAM's libraries follow the instructions in the file /etc/pam.d/login to determine what actions should be taken.

One very important file in /etc/pam.d is /etc/pam.d/system-auth. This file, which is included by many other PAM configuration files, defines 'default' system authentication measures. Modifying this file is a good way to make far-reaching authentication changes, for instance when implementing a centralized authentication service.

warning  Be careful when making changes to PAM's configuration files. The syntax for these files is complex, and modifications can have unexpected consequences. The default configurations shipped with applications should be sufficient for most users.
warning  Running authconfig or system-config-authentication will re-write the PAM configuration files, destroying any manually made changes and replacing them with a series of system defaults. One reference to the configuration file syntax can be found at http://www.kernel.org/pub/linux/libs/pam/Linux-PAM-html/sag-configuration-file.html.
contains 9 rules

Set Password Quality Requirementsgroup

The default pam_pwquality PAM module provides strength checking for passwords. It performs a number of checks, such as making sure passwords are not similar to dictionary words, are of at least a certain length, are not the previous password reversed, and are not simply a change of case from the previous password. It can also require passwords to be in certain character classes. The pam_pwquality module is the preferred way of configuring password requirements.

The pam_cracklib PAM module can also provide strength checking for passwords as the pam_pwquality module. It performs a number of checks, such as making sure passwords are not similar to dictionary words, are of at least a certain length, are not the previous password reversed, and are not simply a change of case from the previous password. It can also require passwords to be in certain character classes.

The man pages pam_pwquality(8) and pam_cracklib(8) provide information on the capabilities and configuration of each.

contains 6 rules

Set Password Quality Requirements with pam_pwqualitygroup

The pam_pwquality PAM module can be configured to meet requirements for a variety of policies.

For example, to configure pam_pwquality to require at least one uppercase character, lowercase character, digit, and other (special) character, make sure that pam_pwquality exists in /etc/pam.d/system-auth: 

password    requisite     pam_pwquality.so try_first_pass local_users_only retry=3 authtok_type=
If no such line exists, add one as the first line of the password section in /etc/pam.d/system-auth. Next, modify the settings in /etc/security/pwquality.conf to match the following: 
difok = 4
minlen = 14
dcredit = -1
ucredit = -1
lcredit = -1
ocredit = -1
maxrepeat = 3
The arguments can be modified to ensure compliance with your organization's security policy. Discussion of each parameter follows.

warning  Note that the password quality requirements are not enforced for the root account for some reason.
contains 6 rules

Set Password Strength Minimum Digit Charactersrule

The pam_pwquality module's dcredit parameter controls requirements for usage of digits in a password. When set to a negative number, any password will be required to contain that many digits. When set to a positive number, pam_pwquality will grant +1 additional length credit for each digit. Modify the dcredit setting in /etc/security/pwquality.conf to require the use of a digit in passwords.

Rationale:

Requiring digits makes password guessing attacks more difficult by ensuring a larger search space.

identifiers:  CCE-27163-5

references:  IA-5(b), IA-5(c), 194, 194, 71, Test attestation on 20121024 by DS

Remediation script:
var_password_pam_dcredit="1"
if egrep -q ^dcredit[[:space:]]*=[[:space:]]*[-]?[[:digit:]]+ /etc/security/pwquality.conf; then
	sed -i "s/^\(dcredit *= *\).*/\1$var_password_pam_dcredit/" /etc/security/pwquality.conf
else
	sed -i "/\(dcredit *= *\).*/a dcredit = $var_password_pam_dcredit" /etc/security/pwquality.conf
fi

Set Password Minimum Lengthrule

The pam_pwquality module's minlen parameter controls requirements for minimum characters required in a password. Add minlen=15 after pam_pwquality to set minimum password length requirements.

Rationale:

Password length is one factor of several that helps to determine strength and how long it takes to crack a password. Use of more characters in a password helps to exponentially increase the time and/or resources required to compromise the password.

identifiers:  CCE-26615-5

references:  IA-5(1)(a), 205, 78, Test attestation on 20140928 by swells

Remediation script:
var_password_pam_minlen="15"
if egrep -q ^minlen[[:space:]]*=[[:space:]]*[[:digit:]]+ /etc/security/pwquality.conf; then
	sed -i "s/^\(minlen *= *\).*/\1$var_password_pam_minlen/" /etc/security/pwquality.conf
else
	sed -i "/\(minlen *= *\).*/a minlen = $var_password_pam_minlen" /etc/security/pwquality.conf
fi

Set Password Strength Minimum Uppercase Charactersrule

The pam_pwquality module's ucredit= parameter controls requirements for usage of uppercase letters in a password. When set to a negative number, any password will be required to contain that many uppercase characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each uppercase character. Modify the ucredit setting in /etc/security/pwquality.conf to require the use of an uppercase character in passwords.

Rationale:

Requiring a minimum number of uppercase characters makes password guessing attacks more difficult by ensuring a larger search space.

identifiers:  CCE-26988-6

references:  IA-5(b), IA-5(c), IA-5(1)(a), 192, 69, Test attestation on 20121024 by DS

Remediation script:
var_password_pam_ucredit="1"
if egrep -q ^ucredit[[:space:]]*=[[:space:]]*[-]?[[:digit:]]+ /etc/security/pwquality.conf; then
	sed -i "s/^\(ucredit *= *\).*/\1$var_password_pam_ucredit/" /etc/security/pwquality.conf
else
	sed -i "/\(ucredit *= *\).*/a ucredit = $var_password_pam_ucredit" /etc/security/pwquality.conf
fi

Set Password Strength Minimum Special Charactersrule

The pam_pwquality module's ocredit= parameter controls requirements for usage of special (or "other") characters in a password. When set to a negative number, any password will be required to contain that many special characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each special character. Modify the ocredit setting in /etc/security/pwquality.conf to require use of a special character in passwords.

Rationale:

Requiring a minimum number of special characters makes password guessing attacks more difficult by ensuring a larger search space.

identifiers:  CCE-27151-0

references:  IA-5(b), IA-5(c), IA-5(1)(a), 1619, 266, Test attestation on 20121024 by DS

Remediation script:
var_password_pam_ocredit="1"
if egrep -q ^ocredit[[:space:]]*=[[:space:]]*[-]?[[:digit:]]+ /etc/security/pwquality.conf; then
	sed -i "s/^\(ocredit *= *\).*/\1$var_password_pam_ocredit/" /etc/security/pwquality.conf
else
	sed -i "/\(ocredit *= *\).*/a ocredit = $var_password_pam_ocredit" /etc/security/pwquality.conf
fi

Set Password Strength Minimum Lowercase Charactersrule

The pam_pwquality module's lcredit parameter controls requirements for usage of lowercase letters in a password. When set to a negative number, any password will be required to contain that many lowercase characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each lowercase character. Modify the lcredit setting in /etc/security/pwquality.conf to require the use of a lowercase character in passwords.

Rationale:

Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.

identifiers:  CCE-27111-4

references:  IA-5(b), IA-5(c), IA-5(1)(a), 193, 70, Test attestation on 20121024 by DS

Remediation script:
var_password_pam_lcredit="1"
if egrep -q ^lcredit[[:space:]]*=[[:space:]]*[-]?[[:digit:]]+ /etc/security/pwquality.conf; then
	sed -i "s/^\(lcredit *= *\).*/\1$var_password_pam_lcredit/" /etc/security/pwquality.conf
else
	sed -i "/\(lcredit *= *\).*/a lcredit = $var_password_pam_lcredit" /etc/security/pwquality.conf
fi

Set Password Strength Minimum Different Charactersrule

The pam_pwquality module's difok parameter controls requirements for usage of different characters during a password change. Modify the difok setting in /etc/security/pwquality.conf to require differing characters when changing passwords. The DoD requirement is 4.

Rationale:

Requiring a minimum number of different characters during password changes ensures that newly changed passwords should not resemble previously compromised ones. Note that passwords which are changed on compromised systems will still be compromised, however.

identifiers:  CCE-26631-2

references:  IA-5(b), IA-5(c), IA-5(1)(b), 195, 72, Test attestation on 20121024 by DS

Remediation script:
var_password_pam_difok="15"
if egrep -q ^difok[[:space:]]*=[[:space:]]*[-]?[[:digit:]]+ /etc/security/pwquality.conf; then
	sed -i "s/^\(difok *= *\).*/\1$var_password_pam_difok/" /etc/security/pwquality.conf
else
	sed -i "/\(difok *= *\).*/a difok = $var_password_pam_difok" /etc/security/pwquality.conf
fi

Set Lockouts for Failed Password Attemptsgroup

The pam_faillock PAM module provides the capability to lock out user accounts after a number of failed login attempts. Its documentation is available in /usr/share/doc/pam-VERSION/txts/README.pam_faillock.

warning  Locking out user accounts presents the risk of a denial-of-service attack. The lockout policy must weigh whether the risk of such a denial-of-service attack outweighs the benefits of thwarting password guessing attacks.
contains 3 rules

Set Deny For Failed Password Attemptsrule

To configure the system to lock out accounts after a number of incorrect login attempts using pam_faillock.so, modify the content of both /etc/pam.d/system-auth and /etc/pam.d/password-auth as follows:

  • add the following line immediately before the pam_unix.so statement in the AUTH section: 
    auth required pam_faillock.so preauth silent deny=3 unlock_time=604800 fail_interval=900
  • add the following line immediately after the pam_unix.so statement in the AUTH section: 
    auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900
  • add the following line immediately before the pam_unix.so statement in the ACCOUNT section: 
    account required pam_faillock.so

Rationale:

Locking out user accounts after a number of incorrect attempts prevents direct password guessing attacks.

identifiers:  CCE-26891-2

references:  AC-7(a), 44, 21

Remediation script:
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-symlink "s/\(^auth.*required.*pam_faillock.so.*preauth.*silent.*\)\(deny *= *\).*/\1\2$var_accounts_passwords_pam_faillock_deny/" $pamFile
			sed -i --follow-symlink "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-symlink "/^auth.*required.*pam_faillock.so.*preauth.*silent.*/ s/$/ deny=$var_accounts_passwords_pam_faillock_deny/" $pamFile
			sed -i --follow-symlink "/^auth.*[default=die].*pam_faillock.so.*authfail.*/ s/$/ 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-symlink "/^auth.*sufficient.*pam_unix.so.*/i auth        required      pam_faillock.so preauth silent deny=$var_accounts_passwords_pam_faillock_deny" $pamFile
		sed -i --follow-symlink "/^auth.*sufficient.*pam_unix.so.*/a auth        [default=die] pam_faillock.so authfail deny=$var_accounts_passwords_pam_faillock_deny" $pamFile
		sed -i --follow-symlink "/^account.*required.*pam_unix.so/i account     required      pam_faillock.so" $pamFile
	fi
done

Set Interval For Counting Failed Password Attemptsrule

Utilizing pam_faillock.so, the fail_interval directive configures the system to lock out accounts after a number of incorrect login attempts. Modify the content of both /etc/pam.d/system-auth and /etc/pam.d/password-auth as follows:

  • add the following line immediately before the pam_unix.so statement in the AUTH section: 
    auth required pam_faillock.so preauth silent deny=3 unlock_time=604800 fail_interval=900
  • add the following line immediately after the pam_unix.so statement in the AUTH section: 
    auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900
  • add the following line immediately before the pam_unix.so statement in the ACCOUNT section: 
    account required pam_faillock.so

Rationale:

Locking out user accounts after a number of incorrect attempts within a specific period of time prevents direct password guessing attacks.

identifiers:  CCE-26763-3

references:  AC-7(a), 44, 21

Limit Password Reuserule

Do not allow users to reuse recent passwords. This can be accomplished by using the remember option for the pam_unix PAM module. In the file /etc/pam.d/system-auth, append remember=5 to the line which refers to the pam_unix.so module, as shown: 

password sufficient pam_unix.so existing_options remember=5
The DoD STIG requirement is 5 passwords.

Rationale:

Preventing re-use of previous passwords helps ensure that a compromised password is not re-used by a user.

identifiers:  CCE-26923-3

references:  IA-5(f), IA-5(1)(e), 200, 77, Test attestation on 20121024 by DS

Remediation script:
var_password_pam_unix_remember="5"
if grep -q "remember=" /etc/pam.d/system-auth; then   
	sed -i --follow-symlink "s/\(remember *= *\).*/\1$var_password_pam_unix_remember/" /etc/pam.d/system-auth
else
	sed -i --follow-symlink "/^password[[:space:]]\+sufficient[[:space:]]\+pam_unix.so/ s/$/ remember=$var_password_pam_unix_remember/" /etc/pam.d/system-auth
fi

Warning Banners for System Accessesgroup

Each system should expose as little information about itself as possible.

System banners, which are typically displayed just before a login prompt, give out information about the service or the host's operating system. This might include the distribution name and the system kernel version, and the particular version of a network service. This information can assist intruders in gaining access to the system as it can reveal whether the system is running vulnerable software. Most network services can be configured to limit what information is displayed.

Many organizations implement security policies that require a system banner provide notice of the system's ownership, provide warning to unauthorized users, and remind authorized users of their consent to monitoring.

contains 3 rules
contains 2 rules

Enable GNOME3 Login Warning Bannerrule

To enable displaying a login warning banner in the GNOME Display Manager's login screen, the banner-message-enable setting must be set under an appropriate configuration file(s) in the /etc/dconf/db/gdm.d directory and locked in /etc/dconf/db/gdm.d/locks directory to prevent user modification. After the settings have been set, run dconf update. To display a banner, this setting must be enabled, and the user must be prevented from making changes. The banner text must also be set.

Rationale:

An appropriate warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers.

identifiers:  CCE-26970-4

references:  AC-8(a), AC-8(b), AC-8(c), 48, 50, 23

Modify the System Login Bannerrule

To configure the system login banner:

Edit /etc/issue. Replace the default text with a message compliant with the local site policy or a legal disclaimer. The DoD required text is either:

You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access controls) to protect USG interests -- not for your personal benefit or privacy.
-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.

OR:

I've read & consent to terms in IS user agreem't.

Rationale:

An appropriate warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers.

identifiers:  CCE-27303-7

references:  AC-8(a), AC-8(b), AC-8(c)(1), AC-8(c)(2), AC-8(c)(3), 48, 50, 1384, 1385, 1386, 1387, 1388, 23, 228, Test attestation on 20121026 by DS

Remediation script:
login_banner_text="You[\s\n]+are[\s\n]+accessing[\s\n]+a[\s\n]+U.S.[\s\n]+Government[\s\n]+\(USG\)[\s\n]+Information[\s\n]+System[\s\n]+\(IS\)[\s\n]+that[\s\n]+is[\s\n]+provided[\s\n]+for[\s\n]+USG-authorized[\s\n]+use[\s\n]+only.[\s\n]*By[\s\n]+using[\s\n]+this[\s\n]+IS[\s\n]+\(which[\s\n]+includes[\s\n]+any[\s\n]+device[\s\n]+attached[\s\n]+to[\s\n]+this[\s\n]+IS\),[\s\n]+you[\s\n]+consent[\s\n]+to[\s\n]+the[\s\n]+following[\s\n]+conditions\:[\s\n]*-[\s\n]*The[\s\n]+USG[\s\n]+routinely[\s\n]+intercepts[\s\n]+and[\s\n]+monitors[\s\n]+communications[\s\n]+on[\s\n]+this[\s\n]+IS[\s\n]+for[\s\n]+purposes[\s\n]+including,[\s\n]+but[\s\n]+not[\s\n]+limited[\s\n]+to,[\s\n]+penetration[\s\n]+testing,[\s\n]+COMSEC[\s\n]+monitoring,[\s\n]+network[\s\n]+operations[\s\n]+and[\s\n]+defense,[\s\n]+personnel[\s\n]+misconduct[\s\n]+\(PM\),[\s\n]+law[\s\n]+enforcement[\s\n]+\(LE\),[\s\n]+and[\s\n]+counterintelligence[\s\n]+\(CI\)[\s\n]+investigations.[\s\n]*-[\s\n]*At[\s\n]+any[\s\n]+time,[\s\n]+the[\s\n]+USG[\s\n]+may[\s\n]+inspect[\s\n]+and[\s\n]+seize[\s\n]+data[\s\n]+stored[\s\n]+on[\s\n]+this[\s\n]+IS.[\s\n]*-[\s\n]*Communications[\s\n]+using,[\s\n]+or[\s\n]+data[\s\n]+stored[\s\n]+on,[\s\n]+this[\s\n]+IS[\s\n]+are[\s\n]+not[\s\n]+private,[\s\n]+are[\s\n]+subject[\s\n]+to[\s\n]+routine[\s\n]+monitoring,[\s\n]+interception,[\s\n]+and[\s\n]+search,[\s\n]+and[\s\n]+may[\s\n]+be[\s\n]+disclosed[\s\n]+or[\s\n]+used[\s\n]+for[\s\n]+any[\s\n]+USG-authorized[\s\n]+purpose.[\s\n]*-[\s\n]*This[\s\n]+IS[\s\n]+includes[\s\n]+security[\s\n]+measures[\s\n]+\(e.g.,[\s\n]+authentication[\s\n]+and[\s\n]+access[\s\n]+controls\)[\s\n]+to[\s\n]+protect[\s\n]+USG[\s\n]+interests[\s\n]+--[\s\n]+not[\s\n]+for[\s\n]+your[\s\n]+personal[\s\n]+benefit[\s\n]+or[\s\n]+privacy.[\s\n]*-[\s\n]*Notwithstanding[\s\n]+the[\s\n]+above,[\s\n]+using[\s\n]+this[\s\n]+IS[\s\n]+does[\s\n]+not[\s\n]+constitute[\s\n]+consent[\s\n]+to[\s\n]+PM,[\s\n]+LE[\s\n]+or[\s\n]+CI[\s\n]+investigative[\s\n]+searching[\s\n]+or[\s\n]+monitoring[\s\n]+of[\s\n]+the[\s\n]+content[\s\n]+of[\s\n]+privileged[\s\n]+communications,[\s\n]+or[\s\n]+work[\s\n]+product,[\s\n]+related[\s\n]+to[\s\n]+personal[\s\n]+representation[\s\n]+or[\s\n]+services[\s\n]+by[\s\n]+attorneys,[\s\n]+psychotherapists,[\s\n]+or[\s\n]+clergy,[\s\n]+and[\s\n]+their[\s\n]+assistants.[\s\n]+Such[\s\n]+communications[\s\n]+and[\s\n]+work[\s\n]+product[\s\n]+are[\s\n]+private[\s\n]+and[\s\n]+confidential.[\s\n]+See[\s\n]+User[\s\n]+Agreement[\s\n]+for[\s\n]+details."
# 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

Configure Sysloggroup

The syslog service has been the default Unix logging mechanism for many years. It has a number of downsides, including inconsistent log format, lack of authentication for received messages, and lack of authentication, encryption, or reliable transport for messages sent over a network. However, due to its long history, syslog is a de facto standard which is supported by almost all Unix applications.

In RHEL 7, rsyslog has replaced ksyslogd as the syslog daemon of choice, and it includes some additional security features such as reliable, connection-oriented (i.e. TCP) transmission of logs, the option to log to database formats, and the encryption of log data en route to a central logging server. This section discusses how to configure rsyslog for best effect, and how to use tools provided with the system to maintain and monitor logs.

contains 2 rules

Ensure rsyslog is Installedrule

Rsyslog is installed by default. The rsyslog package can be installed with the following command: 

$ sudo yum install rsyslog

Rationale:

The rsyslog package provides the rsyslog daemon, which provides system logging services.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AU-9(2), 1311, 1312, Test attestation on 20121024 by DS

Remediation script:
yum -y install rsyslog

Enable rsyslog Servicerule

The rsyslog service provides syslog-style logging by default on RHEL 7. The rsyslog service can be enabled with the following command: 

$ sudo systemctl enable rsyslog

Rationale:

The rsyslog service must be running in order to provide logging services, which are essential to system administration.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AU-12, 1557, 1312, 1311, Test attestation on 20121024 by DS

Remediation script:
#
# Enable rsyslog.service for all systemd targets
#
systemctl enable rsyslog.service

#
# Start rsyslog.service if not currently running
#
systemctl start rsyslog.service

System Accounting with auditdgroup

The audit service provides substantial capabilities for recording system activities. By default, the service audits about SELinux AVC denials and certain types of security-relevant events such as system logins, account modifications, and authentication events performed by programs such as sudo. Under its default configuration, auditd has modest disk space requirements, and should not noticeably impact system performance.
NOTE: The Linux Audit daemon auditd can be configured to use the augenrules program to read audit rules files (*.rules) located in /etc/audit/rules.d location and compile them to create the resulting form of the /etc/audit/audit.rules configuration file during the daemon startup (default configuration). Alternatively, the auditd daemon can use the auditctl utility to read audit rules from the /etc/audit/audit.rules configuration file during daemon startup, and load them into the kernel. The expected behavior is configured via the appropriate ExecStartPost directive setting in the /usr/lib/systemd/system/auditd.service configuration file. To instruct the auditd daemon to use the augenrules program to read audit rules (default configuration), use the following setting: 

ExecStartPost=-/sbin/augenrules --load
in the /usr/lib/systemd/system/auditd.service configuration file. In order to instruct the auditd daemon to use the auditctl utility to read audit rules, use the following setting: 
ExecStartPost=-/sbin/auditctl -R /etc/audit/audit.rules
in the /usr/lib/systemd/system/auditd.service configuration file. Refer to [Service] section of the /usr/lib/systemd/system/auditd.service configuration file for further details.
Government networks often have substantial auditing requirements and auditd can be configured to meet these requirements. Examining some example audit records demonstrates how the Linux audit system satisfies common requirements. The following example from Fedora Documentation available at https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/SELinux_Users_and_Administrators_Guide/sect-Security-Enhanced_Linux-Troubleshooting-Fixing_Problems.html#sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages shows the substantial amount of information captured in a two typical "raw" audit messages, followed by a breakdown of the most important fields. In this example the message is SELinux-related and reports an AVC denial (and the associated system call) that occurred when the Apache HTTP Server attempted to access the /var/www/html/file1 file (labeled with the samba_share_t type): 
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)
  • msg=audit(1226874073.147:96)
    • The number in parentheses is the unformatted time stamp (Epoch time) for the event, which can be converted to standard time by using the date command.
  • { getattr }
    • The item in braces indicates the permission that was denied. getattr indicates the source process was trying to read the target file's status information. This occurs before reading files. This action is denied due to the file being accessed having the wrong label. Commonly seen permissions include getattr, read, and write.
  • comm="httpd"
    • The executable that launched the process. The full path of the executable is found in the exe= section of the system call (SYSCALL) message, which in this case, is exe="/usr/sbin/httpd".
  • path="/var/www/html/file1"
    • The path to the object (target) the process attempted to access.
  • scontext="unconfined_u:system_r:httpd_t:s0"
    • The SELinux context of the process that attempted the denied action. In this case, it is the SELinux context of the Apache HTTP Server, which is running in the httpd_t domain.
  • tcontext="unconfined_u:object_r:samba_share_t:s0"
    • The SELinux context of the object (target) the process attempted to access. In this case, it is the SELinux context of file1. Note: the samba_share_t type is not accessible to processes running in the httpd_t domain.
  • From the system call (SYSCALL) message, two items are of interest:
    • success=no: indicates whether the denial (AVC) was enforced or not. success=no indicates the system call was not successful (SELinux denied access). success=yes indicates the system call was successful - this can be seen for permissive domains or unconfined domains, such as initrc_t and kernel_t.
    • exe="/usr/sbin/httpd": the full path to the executable that launched the process, which in this case, is exe="/usr/sbin/httpd".

contains 27 rules

Configure auditd Rules for Comprehensive Auditinggroup

The auditd program can perform comprehensive monitoring of system activity. This section describes recommended configuration settings for comprehensive auditing, but a full description of the auditing system's capabilities is beyond the scope of this guide. The mailing list linux-audit@redhat.com exists to facilitate community discussion of the auditing system.

The audit subsystem supports extensive collection of events, including:

  • Tracing of arbitrary system calls (identified by name or number) on entry or exit.
  • Filtering by PID, UID, call success, system call argument (with some limitations), etc.
  • Monitoring of specific files for modifications to the file's contents or metadata.

Auditing rules at startup are controlled by the file /etc/audit/audit.rules. Add rules to it to meet the auditing requirements for your organization. Each line in /etc/audit/audit.rules represents a series of arguments that can be passed to auditctl and can be individually tested during runtime. See documentation in /usr/share/doc/audit-VERSION and in the related man pages for more details.

If copying any example audit rulesets from /usr/share/doc/audit-VERSION, be sure to comment out the lines containing arch= which are not appropriate for your system's architecture. Then review and understand the following rules, ensuring rules are activated as needed for the appropriate architecture.

After reviewing all the rules, reading the following sections, and editing as needed, the new rules can be activated as follows: 
$ sudo service auditd restart

contains 27 rules

Records Events that Modify Date and Time Informationgroup

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time. All changes to the system time should be audited.

contains 5 rules

Record attempts to alter time through adjtimexrule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S adjtimex -k audit_time_rules
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S adjtimex -k audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S adjtimex -k audit_time_rules
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S adjtimex -k audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls: 
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169

Record attempts to alter time through settimeofdayrule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S settimeofday -k audit_time_rules
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S settimeofday -k audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S settimeofday -k audit_time_rules
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S settimeofday -k audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls: 
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169

Record Attempts to Alter Time Through stimerule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d for both 32 bit and 64 bit systems: 

-a always,exit -F arch=b32 -S stime -k audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file for both 32 bit and 64 bit systems: 
-a always,exit -F arch=b32 -S stime -k audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined system calls: 
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169

Record Attempts to Alter Time Through clock_settimerule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S clock_settime -k audit_time_rules
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S clock_settime -k audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S clock_settime -k audit_time_rules
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S clock_settime -k audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls: 
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169

Record Attempts to Alter the localtime Filerule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-w /etc/localtime -p wa -k audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-w /etc/localtime -p wa -k audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport and should always be used.

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(b), IR-5, 1487, 169

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
fix_audit_watch_rule "augenrules" "/etc/localtime" "wa" "audit_time_rules"

Record Events that Modify the System's Discretionary Access Controlsgroup

At a minimum the audit system should collect file permission changes for all users and root. Note that the "-F arch=b32" lines should be present even on a 64 bit system. These commands identify system calls for auditing. Even if the system is 64 bit it can still execute 32 bit system calls. Additionally, these rules can be configured in a number of ways while still achieving the desired effect. An example of this is that the "-S" calls could be split up and placed on separate lines, however, this is less efficient. Add the following to /etc/audit/audit.rules: 

-a always,exit -F arch=b32 -S chmod -S fchmod -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod
    -a always,exit -F arch=b32 -S chown -S fchown -S fchownat -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
    -a always,exit -F arch=b32 -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If your system is 64 bit then these lines should be duplicated and the arch=b32 replaced with arch=b64 as follows: 
-a always,exit -F arch=b64 -S chmod -S fchmod -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod
    -a always,exit -F arch=b64 -S chown -S fchown -S fchownat -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
    -a always,exit -F arch=b64 -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

contains 13 rules

Record Events that Modify the System's Discretionary Access Controls - chmodrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S chmod  -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S chmod  -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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>=1000 -F auid!=4294967295 -k *"
	GROUP="chmod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S chmod -S fchmod -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - chownrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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>=1000 -F auid!=4294967295 -k *"
	GROUP="chown"
	FULL_RULE="-a always,exit -F arch=${ARCH} -S chown -S fchown -S fchownat -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - fchmodrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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>=1000 -F auid!=4294967295 -k *"
	GROUP="chmod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S chmod -S fchmod -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - fchmodatrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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>=1000 -F auid!=4294967295 -k *"
	GROUP="chmod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S chmod -S fchmod -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - fchownrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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>=1000 -F auid!=4294967295 -k *"
	GROUP="chown"
	FULL_RULE="-a always,exit -F arch=${ARCH} -S chown -S fchown -S fchownat -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - fchownatrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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>=1000 -F auid!=4294967295 -k *"
	GROUP="chown"
	FULL_RULE="-a always,exit -F arch=${ARCH} -S chown -S fchown -S fchownat -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - fremovexattrrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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 "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit .* -F auid>=1000 -F auid!=4294967295 -k *"
	GROUP="xattr"
	FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - fsetxattrrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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 "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit .* -F auid>=1000 -F auid!=4294967295 -k *"
	GROUP="xattr"
	FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - lchownrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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>=1000 -F auid!=4294967295 -k *"
	GROUP="chown"
	FULL_RULE="-a always,exit -F arch=${ARCH} -S chown -S fchown -S fchownat -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - lremovexattrrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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 "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit .* -F auid>=1000 -F auid!=4294967295 -k *"
	GROUP="xattr"
	FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - lsetxattrrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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 "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit .* -F auid>=1000 -F auid!=4294967295 -k *"
	GROUP="xattr"
	FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - removexattrrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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 "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit .* -F auid>=1000 -F auid!=4294967295 -k *"
	GROUP="xattr"
	FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify the System's Discretionary Access Controls - setxattrrule

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line: 
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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 "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit .* -F auid>=1000 -F auid!=4294967295 -k *"
	GROUP="xattr"
	FULL_RULE="-a always,exit -F arch=${ARCH} -S setxattr -S lsetxattr -S fsetxattr -S removexattr -S lremovexattr -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Record Events that Modify User/Group Informationrule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes: 

-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
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes: 
-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

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

identifiers:  CCE-27192-4

references:  AC-2(4), AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 18, 172, 1403, 1404, 1405, 1684, 1683, 1685, 1686, 476, 239

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# Perform the remediation
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
fix_audit_watch_rule "auditctl" "/etc/group" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/group" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "auditctl" "/etc/passwd" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/passwd" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "auditctl" "/etc/gshadow" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/gshadow" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "auditctl" "/etc/shadow" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/shadow" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "auditctl" "/etc/security/opasswd" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/security/opasswd" "wa" "audit_rules_usergroup_modification"

Record Events that Modify the System's Network Environmentrule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system: 

-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
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system: 
-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

Rationale:

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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=$ARCH -S sethostname -S setdomainname -k audit_rules_networkconfig_modification"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

# Then perform the remediations for the watch rules
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
fix_audit_watch_rule "auditctl" "/etc/issue" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "augenrules" "/etc/issue" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "auditctl" "/etc/issue.net" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "augenrules" "/etc/issue.net" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "auditctl" "/etc/hosts" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "augenrules" "/etc/hosts" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "auditctl" "/etc/sysconfig/network" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "augenrules" "/etc/sysconfig/network" "wa" "audit_rules_networkconfig_modification"

Record Events that Modify the System's Mandatory Access Controlsrule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-w /etc/selinux/ -p wa -k MAC-policy
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-w /etc/selinux/ -p wa -k MAC-policy

Rationale:

The system's mandatory access policy (SELinux) should not be arbitrarily changed by anything other than administrator action. All changes to MAC policy should be audited.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
fix_audit_watch_rule "auditctl" "/etc/selinux/" "wa" "MAC-policy"
fix_audit_watch_rule "augenrules" "/etc/selinux/" "wa" "MAC-policy"

Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)rule

At a minimum the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d: 

-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>=1000 -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>=1000 -F auid!=4294967295 -k access
If the system is 64 bit then also add the following lines: 
-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>=1000 -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>=1000 -F auid!=4294967295 -k access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file: 
-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>=1000 -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>=1000 -F auid!=4294967295 -k access
If the system is 64 bit then also add the following lines: 
-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>=1000 -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>=1000 -F auid!=4294967295 -k access

Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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>=1000 -F auid!=4294967295 -k *"
	# Use escaped BRE regex to specify rule group
	GROUP="\(creat\|open\|truncate\)"
	FULL_RULE="-a always,exit -F arch=$ARCH -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=4294967295 -k access"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"

	# Then fix the -EPERM requirement
	PATTERN="-a always,exit -F arch=$ARCH -S .* -F exit=-EPERM -F auid>=1000 -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>=1000 -F auid!=4294967295 -k access"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"

done

Ensure auditd Collects Information on the Use of Privileged Commandsrule

At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART: 

$ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d for each setuid / setgid program on the system, replacing the SETUID_PROG_PATH part with the full path of that setuid / setgid program in the list: 
-a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=1000 -F auid!=4294967295 -k privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules for each setuid / setgid program on the system, replacing the SETUID_PROG_PATH part with the full path of that setuid / setgid program in the list: 
-a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=1000 -F auid!=4294967295 -k privileged

Rationale:

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-2(4), AU-12(a), AU-12(c), IR-5, 40, Test attestation on 20121024 by DS

Ensure auditd Collects Information on Exporting to Media (successful)rule

At a minimum the audit system should collect media exportation events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system: 

-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=4294967295 -k export
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system: 
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=4294967295 -k export

Rationale:

The unauthorized exportation of data to external media could result in an information leak where classified information, Privacy Act information, and intellectual property could be lost. An audit trail should be created each time a filesystem is mounted to help identify and guard against information loss.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126, Test attestation on 20121024 by DS

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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>=1000 -F auid!=4294967295 -k *"
	GROUP="mount"
	FULL_RULE="-a always,exit -F arch=$ARCH -S mount -F auid>=1000 -F auid!=4294967295 -k export"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Ensure auditd Collects File Deletion Events by Userrule

At a minimum the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system: 

-a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=1000 -F auid!=4294967295 -k delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system: 
-a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=1000 -F auid!=4294967295 -k delete

Rationale:

Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.

identifiers:  CCE-27206-2

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 172, 468

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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>=1000 -F auid!=4294967295 -k *"
	# Use escaped BRE regex to specify rule group
	GROUP="\(rmdir\|unlink\|rename\)"
	FULL_RULE="-a always,exit -F arch=$ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=1000 -F auid!=4294967295 -k delete"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Ensure auditd Collects System Administrator Actionsrule

At a minimum the audit system should collect administrator actions for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d: 

-w /etc/sudoers -p wa -k actions
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file: 
-w /etc/sudoers -p wa -k actions

Rationale:

The actions taken by system administrators should be audited to keep a record of what was executed on the system, as well as, for accountability purposes.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-2(7)(b), AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126, Test attestation on 20121024 by DS

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
fix_audit_watch_rule "auditctl" "/etc/sudoers" "wa" "actions"
fix_audit_watch_rule "augenrules" "/etc/sudoers" "wa" "actions"

Ensure auditd Collects Information on Kernel Module Loading and Unloadingrule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system: 

-w /usr/sbin/insmod -p x -k modules
-w /usr/sbin/rmmod -p x -k modules
-w /usr/sbin/modprobe -p x -k modules
-a always,exit -F arch=ARCH -S init_module -S delete_module -k modules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system: 
-w /usr/sbin/insmod -p x -k modules
-w /usr/sbin/rmmod -p x -k modules
-w /usr/sbin/modprobe -p x -k modules
-a always,exit -F arch=ARCH -S init_module -S delete_module -k modules

Rationale:

The addition/removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.

identifiers:  CCE-27129-6

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 172, 477

Remediation script:

# Include source function library.
. /usr/share/scap-security-guide/remediation_functions

# 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=$ARCH -S init_module -S delete_module -k modules"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

# Then perform the remediations for the watch rules
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
fix_audit_watch_rule "auditctl" "/usr/sbin/insmod" "x" "modules"
fix_audit_watch_rule "augenrules" "/usr/sbin/insmod" "x" "modules"
fix_audit_watch_rule "auditctl" "/usr/sbin/rmmod" "x" "modules"
fix_audit_watch_rule "augenrules" "/usr/sbin/rmmod" "x" "modules"
fix_audit_watch_rule "auditctl" "/usr/sbin/modprobe" "x" "modules"
fix_audit_watch_rule "augenrules" "/usr/sbin/modprobe" "x" "modules"

Servicesgroup

The best protection against vulnerable software is running less software. This section describes how to review the software which Red Hat Enterprise Linux 7 installs on a system and disable software which is not needed. It then enumerates the software packages installed on a default RHEL 7 system and provides guidance about which ones can be safely disabled.

RHEL 7 provides a convenient minimal install option that essentially installs the bare necessities for a functional system. When building RHEL 7 servers, it is highly recommended to select the minimal packages and then build up the system from there.

contains 8 rules

Base Servicesgroup

This section addresses the base services that are installed on a RHEL 7 default installation which are not covered in other sections. Some of these services listen on the network and should be treated with particular discretion. Other services are local system utilities that may or may not be extraneous. In general, system services should be disabled if not required.

contains 5 rules

Disable Automatic Bug Reporting Tool (abrtd)rule

The Automatic Bug Reporting Tool (abrtd) daemon collects and reports crash data when an application crash is detected. Using a variety of plugins, abrtd can email crash reports to system administrators, log crash reports to files, or forward crash reports to a centralized issue tracking system such as RHTSupport. The abrtd service can be disabled with the following command: 

$ sudo systemctl disable abrtd

Rationale:

Mishandling crash data could expose sensitive information about vulnerabilities in software executing on the local machine, as well as sensitive information from within a process's address space or registers.

identifiers:  CCE-26872-2

references:  AC-17(8), CM-7, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Test attestation on 20140921 by JL

Remediation script:
#
# Disable abrtd.service for all systemd targets
#
systemctl disable abrtd.service

#
# Stop abrtd.service if currently running
#
systemctl stop abrtd.service

Disable ntpdate Service (ntpdate)rule

The ntpdate service sets the local hardware clock by polling NTP servers when the system boots. It synchronizes to the NTP servers listed in /etc/ntp/step-tickers or /etc/ntp.conf and then sets the local hardware clock to the newly synchronized system time. The ntpdate service can be disabled with the following command: 

$ sudo systemctl disable ntpdate

Rationale:

The ntpdate service may only be suitable for systems which are rebooted frequently enough that clock drift does not cause problems between reboots. In any event, the functionality of the ntpdate service is now available in the ntpd program and should be considered deprecated.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(8), CM-7, 382, Test attestation on 20121024 by DS

Disable Odd Job Daemon (oddjobd)rule

The oddjobd service exists to provide an interface and access control mechanism through which specified privileged tasks can run tasks for unprivileged client applications. Communication with oddjobd through the system message bus. The oddjobd service can be disabled with the following command: 

$ sudo systemctl disable oddjobd

Rationale:

The oddjobd service may provide necessary functionality in some environments, and can be disabled if it is not needed. Execution of tasks by privileged programs, on behalf of unprivileged ones, has traditionally been a source of privilege escalation security issues.

identifiers:  CCE-RHEL7-CCE-TBD

references:  CM-7, 381, Test attestation on 20121024 by DS

Remediation script:
#
# Disable oddjobd.service for all systemd targets
#
systemctl disable oddjobd.service

#
# Stop oddjobd.service if currently running
#
systemctl stop oddjobd.service

Disable Apache Qpid (qpidd)rule

The qpidd service provides high speed, secure, guaranteed delivery services. It is an implementation of the Advanced Message Queuing Protocol. By default the qpidd service will bind to port 5672 and listen for connection attempts. The qpidd service can be disabled with the following command: 

$ sudo systemctl disable qpidd

Rationale:

The qpidd service is automatically installed when the "base" package selection is selected during installation. The qpidd service listens for network connections, which increases the attack surface of the system. If the system is not intended to receive AMQP traffic, then the qpidd service is not needed and should be disabled or removed.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(8), CM-7, 382

Remediation script:
#
# Disable qpidd.service for all systemd targets
#
systemctl disable qpidd.service

#
# Stop qpidd.service if currently running
#
systemctl stop qpidd.service

Disable Network Router Discovery Daemon (rdisc)rule

The rdisc service implements the client side of the ICMP Internet Router Discovery Protocol (IRDP), which allows discovery of routers on the local subnet. If a router is discovered then the local routing table is updated with a corresponding default route. By default this daemon is disabled. The rdisc service can be disabled with the following command: 

$ sudo systemctl disable rdisc

Rationale:

General-purpose systems typically have their network and routing information configured statically by a system administrator. Workstations or some special-purpose systems often use DHCP (instead of IRDP) to retrieve dynamic network configuration information.

identifiers:  CCE-RHEL7-CCE-TBD

references:  AC-17(8), AC-4, CM-7, 382, Test attestation on 20121024 by DS

Remediation script:
#
# Disable rdisc.service for all systemd targets
#
systemctl disable rdisc.service

#
# Stop rdisc.service if currently running
#
systemctl stop rdisc.service

Cron and At Daemonsgroup

The cron and at services are used to allow commands to be executed at a later time. The cron service is required by almost all systems to perform necessary maintenance tasks, while at may or may not be required on a given system. Both daemons should be configured defensively.

contains 1 rule

Disable At Service (atd)rule

The at and batch commands can be used to schedule tasks that are meant to be executed only once. This allows delayed execution in a manner similar to cron, except that it is not recurring. The daemon atd keeps track of tasks scheduled via at and batch, and executes them at the specified time. The atd service can be disabled with the following command: 

$ sudo systemctl disable atd

Rationale:

The atd service could be used by an unsophisticated insider to carry out activities outside of a normal login session, which could complicate accountability. Furthermore, the need to schedule tasks with at or batch is not common.

identifiers:  CCE-RHEL7-CCE-TBD

references:  CM-7, 381

Remediation script:
#
# Disable atd.service for all systemd targets
#
systemctl disable atd.service

#
# Stop atd.service if currently running
#
systemctl stop atd.service

SSH Servergroup

The SSH protocol is recommended for remote login and remote file transfer. SSH provides confidentiality and integrity for data exchanged between two systems, as well as server authentication, through the use of public key cryptography. The implementation included with the system is called OpenSSH, and more detailed documentation is available from its website, http://www.openssh.org. Its server program is called sshd and provided by the RPM package openssh-server.

contains 1 rule

Configure OpenSSH Server if Necessarygroup

If the system needs to act as an SSH server, then certain changes should be made to the OpenSSH daemon configuration file /etc/ssh/sshd_config. The following recommendations can be applied to this file. See the sshd_config(5) man page for more detailed information.

contains 1 rule

Enable SSH Warning Bannerrule

To enable the warning banner and ensure it is consistent across the system, add or correct the following line in /etc/ssh/sshd_config: 

Banner /etc/issue
Another section contains information on how to create an appropriate system-wide warning banner.

Rationale:

The warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers. Alternatively, systems whose ownership should not be obvious should ensure usage of a banner that does not provide easy attribution.

identifiers:  CCE-27314-4

references:  AC-8(a), AC-8(c)(1), AC-8(c)(2), AC-8(c)(3), 1384, 1385, 1386, 1387, 1388, 228, Test attestation on 20121024 by DS

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

FTP Servergroup

FTP is a common method for allowing remote access to files. Like telnet, the FTP protocol is unencrypted, which means that passwords and other data transmitted during the session can be captured and that the session is vulnerable to hijacking. Therefore, running the FTP server software is not recommended.

However, there are some FTP server configurations which may be appropriate for some environments, particularly those which allow only read-only anonymous access as a means of downloading data available to the public.

contains 1 rule

Use vsftpd to Provide FTP Service if Necessarygroup

The primary vsftpd configuration file is /etc/vsftpd.conf, if that file exists, or /etc/vsftpd/vsftpd.conf if it does not.

contains 1 rule

Create Warning Banners for All FTP Usersrule

Edit the vsftpd configuration file, which resides at /etc/vsftpd/vsftpd.conf by default. Add or correct the following configuration options: 

banner_file=/etc/issue

Rationale:

This setting will cause the system greeting banner to be used for FTP connections as well.

identifiers:  CCE-RHEL7-CCE-TBD

references:  48

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