Permissions on system binaries and configuration files that are too generous could allow an
unauthorized user to gain privileges that they should not have. The permissions set by the
vendor should be maintained. Any deviations from this baseline should be investigated.

The following command will list which files on the system have permissions different from what
is expected by the RPM database:
$ rpm -Va | awk '{ if (substr($0,2,1)=="M") print $NF }'
      Is it the case that there is output?
      

The RPM package management system can check file access permissions of installed software
packages, including many that are important to system security. Verify that the file
permissions of system files and commands match vendor values. Check the file permissions with
the following command:
$ sudo rpm -Va | awk '{ if (substr($0,2,1)=="M") print $NF }'
Output indicates files that do not match vendor defaults.

After locating a file with incorrect permissions, run the following command to determine which
package owns it:
$ rpm -qf FILENAME
                
                
Next, run the following command to reset its permissions to the correct values:
$ sudo rpm --restore PACKAGENAME
                
              

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 Oracle GPG key is necessary to
cryptographically verify packages are from Oracle.

To ensure that the GPG key is installed, run:
$ rpm -q --queryformat "%{SUMMARY}\n" gpg-pubkey
The command should return the string below:
gpg(Oracle OSS group (Open Source Software group) 
      Is it the case that the Oracle GPG Key is not installed?
      

To ensure the system can cryptographically verify base software
packages come from Oracle (and to connect to the Unbreakable Linux Network to
receive them), the Oracle GPG key must properly be installed.
To install the Oracle GPG key, run:
$ sudo uln_register
If the system is not connected to the Internet,
then install the Oracle GPG key from trusted media such as
the Oracle 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-oracle

Alternatively, the key may be pre-loaded during the Oracle installation. In
such cases, the key can be installed by running the following command:
sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-oracle
          

The hashes of important files like system executables should match the
information given by the RPM database. Executables with erroneous hashes could
be a sign of nefarious activity on the system.

The following command will list which files on the system have file hashes different from what
is expected by the RPM database.
$ rpm -Va --noconfig | awk '$1 ~ /..5/'
      Is it the case that there is output?
      

Without cryptographic integrity protections, system executables and files can be altered by
unauthorized users without detection. The RPM package management system can check the hashes
of installed software packages, including many that are important to system security.

To verify that the cryptographic hash of system files and commands matches vendor values, run
the following command to list which files on the system have hashes that differ from what is
expected by the RPM database:
$ rpm -Va --noconfig | grep '^..5'

If the file was not expected to change, investigate the cause of the change using audit logs
or other means. The package can then be reinstalled to restore the file. Run the following
command to determine which package owns the file:
$ rpm -qf FILENAME
                

The package can be reinstalled from a yum repository using the command:
$ sudo yum reinstall PACKAGENAME
                

Alternatively, the package can be reinstalled from trusted media using the command:
$ sudo rpm -Uvh PACKAGENAME
                
              

Display of a standardized and approved use notification before granting access to the operating system
ensures privacy and security notification verbiage used is consistent with applicable federal laws,
Executive Orders, directives, policies, regulations, standards, and guidance.

              
For U.S. Government systems, system use notifications are required only for access via login interfaces
with human users and are not required when such human interfaces do not exist.

To ensure a login warning banner is enabled, run the following:
$ grep banner-message-enable /etc/dconf/db/local.d/*
If properly configured, the output should be true.
To ensure a login warning banner is locked and cannot be changed by a user, run the following:
$ grep banner-message-enable /etc/dconf/db/local.d/locks/*
If properly configured, the output should be /org/gnome/login-screen/banner-message-enable.
      Is it the case that it is not?
      

In the default graphical environment, displaying a login warning banner
in the GNOME Display Manager's login screen can be enabled on the login
screen by setting banner-message-enable to true.

              
To enable, add or edit banner-message-enable to
/etc/dconf/db/local.d/00-security-settings. For example:
[org/gnome/login-screen]
banner-message-enable=true
Once the setting has been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/login-screen/banner-message-enable
After the settings have been set, run dconf update.
The banner text must also be set.

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

To ensure the login warning banner text is properly set, run the following:
$ grep banner-message-text /etc/dconf/db/local.d/*
If properly configured, the proper banner text will appear.
To ensure the login warning banner text is locked and cannot be changed by a user, run the following:
$ grep banner-message-text /etc/dconf/db/local.d/locks/*
If properly configured, the output should be /org/gnome/login-screen/banner-message-text.
      Is it the case that it does not?
      

In the default graphical environment, configuring the login warning banner text
in the GNOME Display Manager's login screen can be configured on the login
screen by setting banner-message-text to 'APPROVED_BANNER'
where APPROVED_BANNER is the approved banner for your environment.

              
To enable, add or edit banner-message-text to

/etc/dconf/db/local.d/00-security-settings. For example:
[org/gnome/login-screen]
banner-message-text='APPROVED_BANNER'
Once the setting has been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/login-screen/banner-message-text

After the settings have been set, run dconf update.
When entering a warning banner that spans several lines, remember
to begin and end the string with ' and use \n for new lines.

Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.

            
System use notifications are required only for access via login interfaces
with human users and are not required when such human interfaces do not
exist.

To check if the system login banner is compliant,
run the following command:

$ cat /etc/issue
      Is it the case that it does not display the required banner?
      

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.
          

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity
of the information system but does not want to logout because of the temporary nature of the absense.

To check the status of the idle screen lock activation, run the following command:

$ gsettings get org.gnome.desktop.screensaver lock-enabled
If properly configured, the output should be true.
To ensure that users cannot change how long until the screensaver locks, run the following:
$ grep lock-enabled /etc/dconf/db/local.d/locks/*
If properly configured, the output for lock-enabled should be /org/gnome/desktop/screensaver/lock-enabled
      Is it the case that screensaver locking is not enabled and/or has not been set or configured correctly?
      

To activate locking of the screensaver in the GNOME3 desktop when it is activated,
add or set lock-enabled to true in
/etc/dconf/db/local.d/00-security-settings. For example:
[org/gnome/desktop/screensaver]
lock-enabled=true

Once the settings have been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/desktop/screensaver/lock-enabled
After the settings have been set, run dconf update.

Smart card login provides two-factor authentication stronger than
that provided by a username and password combination. Smart cards leverage PKI
(public key infrastructure) in order to provide and verify credentials.

To ensure smart card authentication on the login screen is enabled, run the following command:
$ grep enable-smartcard-authentication /etc/dconf/db/local.d/*
The output should be true.
To ensure that users cannot disable smart card authentication on the login screen, run the following:
$ grep enable-smartcard-authentication /etc/dconf/db/local.d/locks/*
If properly configured, the output should be /org/gnome/login-screen/enable-smartcard-authentication
      Is it the case that enable-smartcard-authentication has not been configured or is disabled?
      

In the default graphical environment, smart card authentication
can be enabled on the login screen by setting enable-smartcard-authentication
to true.

              
To enable, add or edit enable-smartcard-authentication to
/etc/dconf/db/local.d/00-security-settings. For example:
[org/gnome/login-screen]
enable-smartcard-authentication=true
Once the setting has been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/login-screen/enable-smartcard-authentication
After the settings have been set, run dconf update.

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity
of the information system but does not want to logout because of the temporary nature of the absense.

To ensure that users cannot change how long until the screensaver locks, run the following:
$ grep lock-enabled /etc/dconf/db/local.d/locks/*
If properly configured, the output for lock-enabled should be /org/gnome/desktop/screensaver/lock-enabled
      Is it the case that screensaver locking is not locked?
      

If not already configured, ensure that users cannot change GNOME3 screensaver lock settings
by adding /org/gnome/desktop/screensaver/lock-enabled
to /etc/dconf/db/local.d/locks/00-security-settings.
For example:
/org/gnome/desktop/screensaver/lock-enabled
After the settings have been set, run dconf update.

Leaving the user list enabled is a security risk since it allows anyone
with physical access to the system to quickly enumerate known user accounts
without logging in.

To ensure the user list is disabled, run the following command:
$ grep disable-user-list /etc/dconf/db/local.d/*
The output should be true.
To ensure that users cannot enable displaying the user list, run the following:
$ grep disable-user-list /etc/dconf/db/local.d/locks/*
If properly configured, the output should be /org/gnome/login-screen/disable-user-list
      Is it the case that disable-user-list has not been configured or is not disabled?
      

In the default graphical environment, users logging directly into the
system are greeted with a login screen that displays all known users.
This functionality should be disabled by setting disable-user-list
to true.

              
To disable, add or edit disable-user-list to
/etc/dconf/db/local.d/00-security-settings. For example:
[org/gnome/login-screen]
disable-user-list=true
Once the setting has been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent
user modification. For example:
/org/gnome/login-screen/disable-user-list
After the settings have been set, run dconf update.

A session time-out lock is a temporary action taken when a user stops work and moves away from
the immediate physical vicinity of the information system but does not logout because of the
temporary nature of the absence. Rather than relying on the user to manually lock their operating
system session prior to vacating the vicinity, GNOME3 can be configured to identify when
a user's session has idled and take action to initiate a session lock.

To check the current idle time-out value, run the following command:
$ gsettings get org.gnome.desktop.session idle-delay
If properly configured, the output should be 'uint32 '.
To ensure that users cannot change the screensaver inactivity timeout setting, run the following:
$ grep idle-delay /etc/dconf/db/local.d/locks/*
If properly configured, the output should be /org/gnome/desktop/session/idle-delay
      Is it the case that idle-delay is set to 0 or a value greater than ?
      

The idle time-out value for inactivity in the GNOME3 desktop is configured via the idle-delay
setting must be set under an appropriate configuration file(s) in the /etc/dconf/db/local.d directory
and locked in /etc/dconf/db/local.d/locks directory to prevent user modification.

              
For example, to configure the system for a 15 minute delay, add the following to
/etc/dconf/db/local.d/00-security-settings:
[org/gnome/desktop/session]
idle-delay=uint32 900
            

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate
physical vicinity of the information system but does not logout because of the temporary nature of the absence.
Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity,
GNOME desktops can be configured to identify when a user's session has idled and take action to initiate the
session lock. As such, users should not be allowed to change session settings.

To ensure that users cannot change session idle and lock settings, run the following:
$ grep 'lock-delay' /etc/dconf/db/local.d/locks/*
If properly configured, the output should return:
/org/gnome/desktop/screensaver/lock-delay
      Is it the case that GNOME3 session settings are not locked or configured properly?
      

If not already configured, ensure that users cannot change GNOME3 screensaver lock settings
by adding /org/gnome/desktop/screensaver/lock-delay
to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/desktop/screensaver/lock-delay
After the settings have been set, run dconf update.

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate
physical vicinity of the information system but does not logout because of the temporary nature of the absence.
Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity,
GNOME desktops can be configured to identify when a user's session has idled and take action to initiate the
session lock. As such, users should not be allowed to change session settings.

To ensure that users cannot change session idle and lock settings, run the following:
$ grep 'idle-delay' /etc/dconf/db/local.d/locks/*
If properly configured, the output should return:
/org/gnome/desktop/session/idle-delay
      Is it the case that idle-delay is not locked?
      

If not already configured, ensure that users cannot change GNOME3 session idle settings
by adding /org/gnome/desktop/session/idle-delay
to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/desktop/session/idle-delay
After the settings have been set, run dconf update.

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate
physical vicinity of the information system but does not logout because of the temporary nature of the absence.
Rather than relying on the user to manually lock their operation system session prior to vacating the vicinity,
operating systems need to be able to identify when a user's session has idled and take action to initiate the
session lock.

                
The screen package allows for a session lock to be implemented and configured.

Run the following command to determine if the screen package is installed: $ rpm -q screen
      Is it the case that the package is not installed?
      

To enable console screen locking, install the screen package.
The screen package can be installed with the following command:

$ sudo yum install screen
Instruct users to begin new terminal sessions with the following command:
$ screen
The console can now be locked with the following key combination:
ctrl+a x
              

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate
physical vicinity of the information system but does not logout because of the temporary nature of the absence.
Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity,
GNOME desktops can be configured to identify when a user's session has idled and take action to initiate the
session lock.

              
Enabling idle activation of the screensaver ensures the screensaver will
be activated after the idle delay.  Applications requiring continuous,
real-time screen display (such as network management products) require the
login session does not have administrator rights and the display station is located in a
controlled-access area.

To check the screensaver mandatory use status, run the following command:
$ gsettings get org.gnome.desktop.screensaver idle-activation-enabled
If properly configured, the output should be true.
To ensure that users cannot disable the screensaver idle inactivity setting, run the following:
$ grep idle-activation-enabled /etc/dconf/db/local.d/locks/*
If properly configured, the output should be /org/gnome/desktop/screensaver/idle-activation-enabled
      Is it the case that idle-activation-enabled is not enabled or configured?
      

To activate the screensaver in the GNOME3 desktop after a period of inactivity,
add or set idle-activation-enabled to true in
/etc/dconf/db/local.d/00-security-settings. For example:
[org/gnome/desktop/screensaver]
idle-activation-enabled=true
Once the setting has been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/desktop/screensaver/idle-activation-enabled
After the settings have been set, run dconf update.

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity
of the information system but does not want to logout because of the temporary nature of the absense.

To ensure that users cannot disable the screensaver idle inactivity setting, run the following:
$ grep idle-activation-enabled /etc/dconf/db/local.d/locks/*
If properly configured, the output should be /org/gnome/desktop/screensaver/idle-activation-enabled
      Is it the case that idle-activation-enabled is not locked?
      

If not already configured, ensure that users cannot change GNOME3 screensaver lock settings
by adding /org/gnome/desktop/screensaver/idle-activation-enabled
to /etc/dconf/db/local.d/00-security-settings.
For example:
/org/gnome/desktop/screensaver/idle-activation-enabled
After the settings have been set, run dconf update.

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity
of the information system but does not want to logout because of the temporary nature of the absense.

To check that the screen locks immediately when activated, run the following command:
$ gsettings get org.gnome.desktop.screensaver lock-delay
If properly configured, the output should be 'uint32 '.
      Is it the case that the screensaver lock delay is missing, or is set to a value greater than ?
      

To activate the locking delay of the screensaver in the GNOME3 desktop when
the screensaver is activated, add or set lock-delay to uint32 
               in
/etc/dconf/db/local.d/00-security-settings. For example:
[org/gnome/desktop/screensaver]
lock-delay=uint32 
              
After the settings have been set, run dconf update.

Including system-auth from the passwd module ensures that the user must pass through
the PAM configuration for system authentication as found in /etc/pam.d/system-auth
when changing passwords.

To verify that PAM implements system-auth when changing passwords
run the following command:
# cat /etc/pam.d/passwd | grep -i substack | grep -i system-auth
password substack system-auth
      Is it the case that /etc/pam.d/passwd does not implement /etc/pam.d/system-auth?
      

Verify that pam is configured to use /etc/pam.d/system-auth
when changing passwords. Look for the following line in /etc/pam.d/passwd:
password substack system-auth
            

Setting the password retry prompts that are permitted on a per-session basis to a low value
requires some software, such as SSH, to re-connect. This can slow down and
draw additional attention to some types of password-guessing attacks. Note that this
is different from account lockout, which is provided by the pam_faillock module.

Verify Oracle Linux 7 is configured to limit the "pwquality" retry option to .


Check for the use of the "pwquality" retry option in the PAM files with the following command:

$ grep pam_pwquality /etc/pam.d/system-auth


password requisite pam_pwquality.so retry=
      Is it the case that the value of "retry" is set to "0" or greater than "", or is missing?
      

To configure the number of retry prompts that are permitted per-session:

Edit the pam_pwquality.so statement in

/etc/pam.d/system-auth to show


retry=
                , or a lower value if site
policy is more restrictive. The DoD requirement is a maximum of 3 prompts
per session.

Use of a complex password helps to increase the time and resources required to compromise the password.
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts
at guessing and brute-force attacks.

                
Password complexity is one factor of several that determines how long it takes to crack a password. The more
complex the password, the greater the number of possible combinations that need to be tested before
the password is compromised.

Verify that Oracle Linux 7 enforces password complexity by requiring that at least one upper-case character.

Check the value for "ucredit" with the following command:

$ sudo grep ucredit /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf

ucredit = -1
      Is it the case that the value of "ucredit" is a positive number or is commented out?
      

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.

Use of a complex password helps to increase the time and resources required
to compromise the password. Password complexity, or strength, is a measure of
the effectiveness of a password in resisting attempts at guessing and brute-force
attacks.

Password complexity is one factor of several that determines how long it takes
to crack a password. The more complex the password, the greater the number of
possble combinations that need to be tested before the password is compromised.
Requiring a minimum number of lowercase characters makes password guessing attacks
more difficult by ensuring a larger search space.

Verify that Oracle Linux 7 enforces password complexity by requiring that at least one lower-case character.

Check the value for "lcredit" with the following command:

$ sudo grep lcredit /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf

/etc/security/pwquality.conf:lcredit = -1
      Is it the case that the value of "lcredit" is a positive number or is commented out?
      

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.

Use of a complex password helps to increase the time and resources required
to compromise the password. Password complexity, or strength, is a measure of
the effectiveness of a password in resisting attempts at guessing and brute-force
attacks.

                
Password complexity is one factor of several that determines how long it takes
to crack a password. The more complex the password, the greater the number of
possible combinations that need to be tested before the password is compromised.
Requiring digits makes password guessing attacks more difficult by ensuring a larger
search space.

Verify that Oracle Linux 7 enforces password complexity by requiring that at least one numeric character be used.

Check the value for "dcredit" with the following command:

$ sudo grep dcredit /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf

/etc/security/pwquality.conf:dcredit = 
      Is it the case that the value of "dcredit" is a positive number or is commented out?
      

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.

Use of a complex password helps to increase the time and resources required
to compromise the password. Password complexity, or strength, is a measure of
the effectiveness of a password in resisting attempts at guessing and brute-force
attacks.

                
Password complexity is one factor of several that determines how long it takes
to crack a password. The more complex the password, the greater the number of
possible combinations that need to be tested before the password is compromised.
Requiring a minimum number of special characters makes password guessing attacks
more difficult by ensuring a larger search space.

Verify that Oracle Linux 7 enforces password complexity by requiring that at least one special character with the following command:

$ sudo grep ocredit /etc/security/pwquality.conf /etc/security/pwquality.conf.d/*.conf

ocredit = 
      Is it the case that value of "ocredit" is a positive number or is commented out?
      

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 equal 
to require use of a special character in passwords.

Use of a complex password helps to increase the time and resources
required to compromise the password. Password complexity, or strength,
is a measure of the effectiveness of a password in resisting attempts
at guessing and brute–force attacks.

                
Password complexity is one factor of several that determines how long
it takes to crack a password. The more complex the password, the
greater the number of possible combinations that need to be tested
before the password is compromised.

                
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.

Verify the value of the "difok" option in "/etc/security/pwquality.conf" with the following command:

$ sudo grep difok /etc/security/pwquality.conf

difok = 
      Is it the case that the value of "difok" is set to less than "", or is commented out?
      

The pam_pwquality module's difok parameter sets the number of characters
in a password that must not be present in and old password during a password change.

                
Modify the difok setting in /etc/security/pwquality.conf
to equal  to require differing characters
when changing passwords.

Use of a complex password helps to increase the time and resources required to compromise the password.
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts
at guessing and brute-force attacks.

                
Password complexity is one factor of several that determines how long it takes to crack a password. The
more complex the password, the greater the number of possible combinations that need to be tested before
the password is compromised.

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

Verify the value of the "minclass" option in "/etc/security/pwquality.conf" with the following command:

$ grep minclass /etc/security/pwquality.conf

minclass = 
      Is it the case that the value of "minclass" is set to less than "" or is commented out?
      

The pam_pwquality module's minclass parameter controls
requirements for usage of different character classes, or types, of character
that must exist in a password before it is considered valid. For example,
setting this value to three (3) requires that any password must have characters
from at least three different categories in order to be approved. The default
value is zero (0), meaning there are no required classes. There are four
categories available:

* Upper-case characters
* Lower-case characters
* Digits
* Special characters (for example, punctuation)

Modify the minclass setting in /etc/security/pwquality.conf entry
to require 
differing categories of characters when changing passwords.

Use of a complex password helps to increase the time and resources required to compromise the password.
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at
guessing and brute-force attacks.

                
Password complexity is one factor of several that determines how long it takes to crack a password. The more
complex the password, the greater the number of possible combinations that need to be tested before the
password is compromised.

                
Passwords with excessive repeating characters may be more vulnerable to password-guessing attacks.

Verify the value of the "maxrepeat" option in "/etc/security/pwquality.conf" with the following command:

$ grep maxrepeat /etc/security/pwquality.conf

maxrepeat = 
      Is it the case that the value of "maxrepeat" is set to more than "" or is commented out?
      

The pam_pwquality module's maxrepeat parameter controls requirements for
consecutive repeating characters. When set to a positive number, it will reject passwords
which contain more than that number of consecutive characters. Modify the maxrepeat setting
in /etc/security/pwquality.conf to equal  to prevent a
run of ( + 1) or more identical characters.

Use of a complex password helps to increase the time and resources required to compromise the password.
Password complexity, or strength, is a measure of the effectiveness of a password in resisting
attempts at guessing and brute-force attacks.

Password complexity is one factor of several that determines how long it takes to crack a password. The
more complex a password, the greater the number of possible combinations that need to be tested before the
password is compromised.

Verify the value of the "maxclassrepeat" option in "/etc/security/pwquality.conf" with the following command:

$ grep maxclassrepeat /etc/security/pwquality.conf

maxclassrepeat = 
      Is it the case that the value of "maxclassrepeat" is set to "0", more than "" or is commented out?
      

The pam_pwquality module's maxclassrepeat parameter controls requirements for
consecutive repeating characters from the same character class. When set to a positive number, it will reject passwords
which contain more than that number of consecutive characters from the same character class. Modify the
maxclassrepeat setting in /etc/security/pwquality.conf to equal 
to prevent a run of ( + 1) or more identical characters.

When using the authconfig utility to modify authentication configuration settings,
the "system-auth" and "password-auth" files and any custom settings that they may
contain are overwritten.

Verify "system-auth" and "password-auth" files are symbolic
links pointing to "system-auth-local" and "password-auth-local":
$ sudo ls -l /etc/pam.d/{password,system}-auth
      Is it the case that The system-auth and password-auth files are not symbolic links or they
do not point to system-auth-local password-auth-local?
      

Oracle Linux 7 must be configured to prevent overwriting of custom authentication
configuration settings by the authconfig utility.
This can be avoided by creating new local configuration files and creating new or moving
existing symbolic links to them. The authconfig utility will recognize the local configuration
files and not overwrite them, while writing its own settings to the original configuration
files.

Passwords need to be protected at all times, and encryption is the standard method for
protecting passwords. If passwords are not encrypted, they can be plainly read
(i.e., clear text) and easily compromised. Passwords that are encrypted with a weak algorithm
are no more protected than if they are kept in plain text.

              
This setting ensures user and group account administration utilities are configured to store
only encrypted representations of passwords. Additionally, the crypt_style
configuration option in /etc/libuser.conf ensures the use of a strong hashing
algorithm that makes password cracking attacks more difficult.

Inspect the password section of /etc/pam.d/system-auth
and ensure that the pam_unix.so module is configured to use the argument
:

$ sudo grep "^password.*pam_unix\.so.*" /etc/pam.d/system-auth

password sufficient pam_unix.so 
      Is it the case that "" is missing, or is commented out?
      

The PAM system service can be configured to only store encrypted representations of passwords.
In "/etc/pam.d/system-auth", the password section of the file controls which
PAM modules to execute during a password change.

Set the pam_unix.so module in the password section to include the option

                
               and no other hashing
algorithms as shown below:

              password    sufficient    pam_unix.so 
                other arguments...
              
              
This will help ensure that new passwords for local users will be stored using the
 algorithm.

Passwords need to be protected at all times, and encryption is the standard method for
protecting passwords. If passwords are not encrypted, they can be plainly read
(i.e., clear text) and easily compromised. Passwords that are encrypted with a weak algorithm
are no more protected than if they are kept in plain text.

              
Using a stronger hashing algorithm makes password cracking attacks more difficult.

Verify that the shadow password suite configuration is set to encrypt password with a FIPS 140-2 approved cryptographic hashing algorithm.

Check the hashing algorithm that is being used to hash passwords with the following command:

$ sudo grep -i ENCRYPT_METHOD /etc/login.defs

ENCRYPT_METHOD 
      Is it the case that ENCRYPT_METHOD is not set to ?
      

In /etc/login.defs, add or update the following line to ensure the system will use
 as the hashing algorithm:
ENCRYPT_METHOD 
              
            

Passwords need to be protected at all times, and encryption is the standard method for
protecting passwords. If passwords are not encrypted, they can be plainly read
(i.e., clear text) and easily compromised. Passwords that are encrypted with a weak algorithm
are no more protected than if they are kept in plain text.

              
This setting ensures user and group account administration utilities are configured to store
only encrypted representations of passwords. Additionally, the crypt_style
configuration option in /etc/libuser.conf ensures the use of a strong hashing
algorithm that makes password cracking attacks more difficult.

Verify that the libuser is set to encrypt password with a FIPS 140-2 approved cryptographic hashing algorithm.

Check the hashing algorithm that is being used to hash passwords with the following command:

$ sudo grep -i crypt_style /etc/libuser.conf

crypt_style = 
      Is it the case that crypt_style is not set to sha512?
      

In /etc/libuser.conf, add or correct the following line in its [defaults]
section to ensure the system will use the 
algorithm for password hashing:
crypt_style = 
              
            

Enforcing a minimum password lifetime helps to prevent repeated password
changes to defeat the password reuse or history enforcement requirement. If
users are allowed to immediately and continually change their password,
then the password could be repeatedly changed in a short period of time to
defeat the organization's policy regarding password reuse.

              
Setting the minimum password age protects against users cycling back to a
favorite password after satisfying the password reuse requirement.

Verify Oracle Linux 7 enforces 24 hours/one day as the minimum password lifetime for new user accounts.

Check for the value of "PASS_MIN_DAYS" in "/etc/login.defs" with the following command:

$ grep -i pass_min_days /etc/login.defs

PASS_MIN_DAYS 
      Is it the case that the "PASS_MIN_DAYS" parameter value is not "" or greater, or is commented out?
      

To specify password minimum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MIN_DAYS 
              
A value of 1 day is considered sufficient for many
environments. The DoD requirement is 1.
The profile requirement is 
                
              .

Enforcing a minimum password lifetime helps to prevent repeated password
changes to defeat the password reuse or history enforcement requirement. If
users are allowed to immediately and continually change their password, the
password could be repeatedly changed in a short period of time to defeat the
organization's policy regarding password reuse.

Verify that Oracle Linux 7 has configured the minimum time period between password changes for each user account is one day or greater with the following command:

$ sudo awk -F: '$4 < 1 {print $1 " " $4}' /etc/shadow
      Is it the case that any results are returned that are not associated with a system account?
      

Configure non-compliant accounts to enforce a 24 hours/1 day minimum password
lifetime by running the following command:
$ sudo chage -m 1 USER
              
            

Any password, no matter how complex, can eventually be cracked. Therefore, passwords
need to be changed periodically. If the operating system does not limit the lifetime
of passwords and force users to change their passwords, there is the risk that the
operating system passwords could be compromised.

              
Setting the password maximum age ensures users are required to
periodically change their passwords. Requiring shorter password lifetimes
increases the risk of users writing down the password in a convenient
location subject to physical compromise.

Verify that Oracle Linux 7 enforces a -day maximum password lifetime for new user accounts by running the following command:

$ grep -i pass_max_days /etc/login.defs

PASS_MAX_DAYS 
      Is it the case that the "PASS_MAX_DAYS" parameter value is greater than "", or commented out?
      

To specify password maximum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MAX_DAYS 
              
A value of 180 days is sufficient for many environments.
The DoD requirement is 60.
The profile requirement is 
                
              .

Any password, no matter how complex, can eventually be cracked. Therefore,
passwords need to be changed periodically. If the operating system does
not limit the lifetime of passwords and force users to change their
passwords, there is the risk that the operating system passwords could be
compromised.

Check whether the maximum time period for existing passwords is restricted to  days with the following commands:

$ sudo awk -F: '$5 > 60 {print $1 " " $5}' /etc/shadow

$ sudo awk -F: '$5 <= 0 {print $1 " " $5}' /etc/shadow
      Is it the case that any results are returned that are not associated with a system account?
      

Configure non-compliant accounts to enforce a -day maximum password lifetime
restriction by running the following command:
$ sudo chage -M 
                USER
              
            

If temporary user accounts remain active when no longer needed or for
an excessive period, these accounts may be used to gain unauthorized access.
To mitigate this risk, automated termination of all temporary accounts
must be set upon account creation.

            

Verify that temporary accounts have been provisioned with an expiration date
of 72 hours. For every temporary account, run the following command to
obtain its account aging and expiration information:
$ sudo chage -l temporary_account_name
Verify each of these accounts has an expiration date set within 72 hours or
as documented.
      Is it the case that any temporary accounts have no expiration date set or do not expire within 72 hours?
      

Temporary accounts are established as part of normal account activation
procedures when there is a need for short-term accounts. In the event
temporary accounts are required, configure the system to
terminate them after a documented time period. For every temporary account, run the following command to set an expiration date on
it, substituting 
                USER
               and 
                YYYY-MM-DD
              
appropriately:
$ sudo chage -E YYYY-MM-DD USER
              
              
                YYYY-MM-DD
               indicates the documented expiration date for the
account. For U.S. Government systems, the operating system must be
configured to automatically terminate these types of accounts after a
period of 72 hours.

The shorter the password, the lower the number of possible combinations
that need to be tested before the password is compromised.

Password complexity, or strength, is a measure of the effectiveness of a
password in resisting attempts at guessing and brute-force attacks.
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.

Verify that Oracle Linux 7 enforces a minimum -character password length with the following command:

$ grep minlen /etc/security/pwquality.conf

minlen = 
      Is it the case that the command does not return a "minlen" value of "" or greater, does not return a line, or the line is commented out?
      

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

If an account has an empty password, anyone could log in and
run commands with the privileges of that account. Accounts with
empty passwords should never be used in operational environments.

To verify that null passwords cannot be used, run the following command:

$ grep nullok /etc/pam.d/system-auth /etc/pam.d/password-auth

If this produces any output, it may be possible to log into accounts
with empty passwords. Remove any instances of the nullok option to
prevent logins with empty passwords.
      Is it the case that NULL passwords can be used?
      

If an account is configured for password authentication
but does not have an assigned password, it may be possible to log
into the account without authentication. Remove any instances of the
nullok in

/etc/pam.d/system-auth and
/etc/pam.d/password-auth

to prevent logins with empty passwords.

If an account has an empty password, anyone could log in and
run commands with the privileges of that account. Accounts with
empty passwords should never be used in operational environments.

To verify that null passwords cannot be used, run the following command:
$ sudo awk -F: '!$2 {print $1}' /etc/shadow
If this produces any output, it may be possible to log into accounts
with empty passwords.
      Is it the case that Blank or NULL passwords can be used?
      

Check the "/etc/shadow" file for blank passwords with the
following command:
$ sudo awk -F: '!$2 {print $1}' /etc/shadow
If the command returns any results, this is a finding.
Configure all accounts on the system to have a password or lock
the account with the following commands:
Perform a password reset:
$ sudo passwd [username]
Lock an account:
$ sudo passwd -l [username]
            

Configuring this setting for the SSH daemon provides additional assurance
that remote login via SSH will require a password, even in the event of
misconfiguration elsewhere.

To determine how the SSH daemon's PermitEmptyPasswords option is set, run the following command:

$ sudo grep -i PermitEmptyPasswords /etc/ssh/sshd_config

If a line indicating no is returned, then the required value is set.

      Is it the case that the required value is not set?
      

Disallow SSH login with empty passwords.
The default SSH configuration disables logins with empty passwords. The appropriate
configuration is used if no value is set for PermitEmptyPasswords.

To explicitly disallow SSH login from accounts with empty passwords,
add or correct the following line in


/etc/ssh/sshd_config:


            PermitEmptyPasswords no
Any accounts with empty passwords should be disabled immediately, and PAM configuration
should prevent users from being able to assign themselves empty passwords.

Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system.
Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials.
Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained.

To verify the INACTIVE setting, run the following command:
$ grep "INACTIVE" /etc/default/useradd
The output should indicate the INACTIVE configuration option is set
to an appropriate integer as shown in the example below:
$ grep "INACTIVE" /etc/default/useradd
INACTIVE=
      Is it the case that the value of INACTIVE is greater than the expected value or is -1?
      

To specify the number of days after a password expires (which
signifies inactivity) until an account is permanently disabled, add or correct
the following line in /etc/default/useradd:
INACTIVE=
                  
                
              
If a password is currently on the verge of expiration, then

                
              
day(s) remain(s) until the account is automatically
disabled. However, if the password will not expire for another 60 days, then 60
days plus 
                
               day(s) could
elapse until the account would be automatically disabled. See the
useradd man page for more information.

By limiting the number of failed logon attempts the risk of unauthorized system
access via user password guessing, otherwise known as brute-forcing, is reduced.
Limits are imposed by locking the account.

Verify Oracle Linux 7 is configured to lock an account until released by an administrator
after  unsuccessful logon
attempts with the command:

$ grep 'unlock_time =' /etc/security/faillock.conf
unlock_time = 
      Is it the case that the "unlock_time" option is not set to "",
the line is missing, or commented out?
      

This rule configures the system to lock out accounts during a specified time period after a
number of incorrect login attempts using pam_faillock.so.

Ensure that the file /etc/security/faillock.conf contains the following entry:
unlock_time= where
interval-in-seconds is 
                
               or greater.

pam_faillock.so module requires multiple entries in pam files. These entries must be carefully
defined to work as expected. In order to avoid any errors when manually editing these files,
it is recommended to use the appropriate tools, such as authselect or authconfig,
depending on the OS version.

If unlock_time is set to 0, manual intervention by an administrator is required
to unlock a user. This should be done using the faillock tool.

By limiting the number of failed logon attempts, the risk of unauthorized system access via
user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking
the account.

Verify Oracle Linux 7 is configured to lock the root account after 
unsuccessful logon attempts with the command:

$ grep even_deny_root /etc/security/faillock.conf
even_deny_root
      Is it the case that the "even_deny_root" option is not set, is missing or commented out?
      

This rule configures the system to lock out the root account after a number of
incorrect login attempts using pam_faillock.so.

pam_faillock.so module requires multiple entries in pam files. These entries must be carefully
defined to work as expected. In order to avoid errors when manually editing these files, it is
recommended to use the appropriate tools, such as authselect or authconfig,
depending on the OS version.

Some sudo configurtion options allow users to run programs without re-authenticating.
Use of these configuration options makes it easier for one compromised accound to be used to
compromise other accounts.

To determine whether sudo command includes configuration files from the appropriate directory,
run the following command:
$ sudo grep -rP '^[#@]include(dir)?' /etc/sudoers /etc/sudoers.d
If only the line /etc/sudoers:#includedir /etc/sudoers.d is returned, then the drop-in include configuration is set correctly.
Any other line returned is a finding.
      Is it the case that the /etc/sudoers doesn't include /etc/sudores.d or includes other directories??
      

Administrators can configure authorized sudo users via drop-in files, and it is possible to include
other directories and configuration files from the file currently being parsed.

Make sure that /etc/sudoers only includes drop-in configuration files from /etc/sudoers.d,
or that no drop-in file is included.
Either the /etc/sudoers should contain only one #includedir directive pointing to
/etc/sudoers.d, and no file in /etc/sudoers.d/ should include other files or directories;
Or the /etc/sudoers should not contain any #include,
@include, #includedir or @includedir directives.
Note that the '#' character doesn't denote a comment in the configuration file.

Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.

            
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate.

To determine if NOPASSWD has been configured for sudo, run the following command:
$ sudo grep -ri nopasswd /etc/sudoers /etc/sudoers.d/
The command should return no output.
      Is it the case that nopasswd is specified in the sudo config files?
      

The sudo NOPASSWD tag, when specified, allows a user to execute
commands using sudo without having to authenticate. This should be disabled
by making sure that the NOPASSWD tag does not exist in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/.

If the "sudoers" file is not configured correctly, any user defined
on the system can initiate privileged actions on the target system.

Determine if "sudoers" file restricts sudo access run the following commands:
$ sudo grep -PR '^\s*ALL\s+ALL\=\(ALL\)\s+ALL\s*$' /etc/sudoers /etc/sudoers.d/*
$ sudo grep -PR '^\s*ALL\s+ALL\=\(ALL\:ALL\)\s+ALL\s*$' /etc/sudoers /etc/sudoers.d/*
      Is it the case that either of the commands returned a line?
      

The sudo command allows a user to execute programs with elevated
(administrator) privileges. It prompts the user for their password
and confirms your request to execute a command by checking a file,
called sudoers.
Restrict privileged actions by removing the following entries from the sudoers file:
ALL ALL=(ALL) ALL
            ALL ALL=(ALL:ALL) ALL
          

If the rootpw, targetpw, or runaspw flags are defined and not disabled, by default the operating system will prompt
the invoking user for the "root" user password.

Run the following command to Verify that the sudoers security policy is configured to use the invoking user's password for privilege escalation:
 sudo cvtsudoers -f sudoers /etc/sudoers | grep -E '^Defaults !?(rootpw|targetpw|runaspw)' 
or if cvtsudoers not supported:
 sudo find /etc/sudoers /etc/sudoers.d \( \! -name '*~' -a \! -name '*.*' \) -exec grep -E --with-filename '^[[:blank:]]*Defaults[[:blank:]](.*[[:blank:]])?!?\b(rootpw|targetpw|runaspw)' -- {} \; 
If no results are returned, this is a finding.
If conflicting results are returned, this is a finding.
If "Defaults !targetpw" is not defined, this is a finding.
If "Defaults !rootpw" is not defined, this is a finding.
If "Defaults !runaspw" is not defined, this is a finding.
      Is it the case that invoke user passwd when using sudo?
      

The sudoers security policy requires that users authenticate themselves before they can use sudo.
When sudoers requires authentication, it validates the invoking user's credentials.
The expected output for:
 sudo cvtsudoers -f sudoers /etc/sudoers | grep -E '^Defaults !?(rootpw|targetpw|runaspw)$' 
             Defaults !targetpw
      Defaults !rootpw
      Defaults !runaspw 
or if cvtsudoers not supported:
 sudo find /etc/sudoers /etc/sudoers.d \( \! -name '*~' -a \! -name '*.*' \) -exec grep -E --with-filename '^[[:blank:]]*Defaults[[:blank:]](.*[[:blank:]])?!?\b(rootpw|targetpw|runaspw)' -- {} \; 
             /etc/sudoers:Defaults !targetpw
      /etc/sudoers:Defaults !rootpw
      /etc/sudoers:Defaults !runaspw 
          

Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.

            
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate.

Verify the operating system requires re-authentication
when using the "sudo" command to elevate privileges, run the following command:
sudo grep -ri '^Defaults.*timestamp_timeout' /etc/sudoers /etc/sudoers.d
The output should be:
/etc/sudoers:Defaults timestamp_timeout=0 or "timestamp_timeout" is set to a positive number.
If conflicting results are returned, this is a finding.
      Is it the case that timestamp_timeout is not set with the appropriate value for sudo?
      

The sudo timestamp_timeout tag sets the amount of time sudo password prompt waits.
The default timestamp_timeout value is 5 minutes.
The timestamp_timeout should be configured by making sure that the
timestamp_timeout tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/.
If the value is set to an integer less than 0, the user's time stamp will not expire
and the user will not have to re-authenticate for privileged actions until the user's session is terminated.

Without re-authentication, users may access resources or perform tasks for which they do not
have authorization. When operating systems provide the capability to escalate a functional
capability, it is critical the user re-authenticate.

Verify the operating system is not configured to bypass password requirements for privilege
escalation. Check the configuration of the "/etc/pam.d/sudo" file with the following command:
$ sudo grep pam_succeed_if /etc/pam.d/sudo
      Is it the case that system is configured to bypass password requirements for privilege escalation?
      

Verify the operating system is not configured to bypass password requirements for privilege
escalation. Check the configuration of the "/etc/pam.d/sudo" file with the following command:
$ sudo grep pam_succeed_if /etc/pam.d/sudo
If any occurrences of "pam_succeed_if" is returned from the command, this is a finding.

Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.

            
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate.

To determine if !authenticate has not been configured for sudo, run the following command:
$ sudo grep -r \!authenticate /etc/sudoers /etc/sudoers.d/
The command should return no output.
      Is it the case that !authenticate is specified in the sudo config files?
      

The sudo !authenticate option, when specified, allows a user to execute commands using
sudo without having to authenticate. This should be disabled by making sure that the
!authenticate option does not exist in /etc/sudoers configuration file or
any sudo configuration snippets in /etc/sudoers.d/.

Unprivileged access to the kernel syslog can expose sensitive kernel
address information.

The runtime status of the kernel.dmesg_restrict kernel parameter can be queried
by running the following command:
$ sysctl kernel.dmesg_restrict
1.

      Is it the case that the correct value is not returned?
      

To set the runtime status of the kernel.dmesg_restrict kernel parameter, run the following command: $ sudo sysctl -w kernel.dmesg_restrict=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: kernel.dmesg_restrict = 1
          

Increasing the time between a failed authentication attempt and re-prompting to
enter credentials helps to slow a single-threaded brute force attack.

Verify Oracle Linux 7 enforces a delay of at least  seconds between console logon prompts following a failed logon attempt with the following command:

$ sudo grep -i "FAIL_DELAY" /etc/login.defs
FAIL_DELAY 
      Is it the case that the value of "FAIL_DELAY" is not set to "" or greater, or the line is commented out?
      

To ensure the logon failure delay controlled by /etc/login.defs is set properly,
add or correct the FAIL_DELAY setting in /etc/login.defs to read as follows:
FAIL_DELAY 
            
          

Failure to restrict system access to authenticated users negatively impacts operating
system security.

To verify that automatic logins are disabled, run the following command:
$ grep -Pzoi "^\[daemon]\\nautomaticlogin.*" /etc/gdm/custom.conf
The output should show the following:
[daemon]
AutomaticLoginEnable=false
      Is it the case that GDM allows users to automatically login?
      

The GNOME Display Manager (GDM) can allow users to automatically login without
user interaction or credentials. User should always be required to authenticate themselves
to the system that they are authorized to use. To disable user ability to automatically
login to the system, set the AutomaticLoginEnable to false in the
[daemon] section in /etc/gdm/custom.conf. For example:
[daemon]
AutomaticLoginEnable=false
            

Failure to restrict system access to authenticated users negatively impacts operating
system security.

To verify that timed logins are disabled, run the following command:
$ grep -Pzoi "^\[daemon]\\ntimedlogin.*" /etc/gdm/custom.conf
The output should show the following:
[daemon]
TimedLoginEnable=false
      Is it the case that GDM allows a guest to login without credentials?
      

The GNOME Display Manager (GDM) can allow users to login without credentials
which can be useful for public kiosk scenarios. Allowing users to login without credentials
or "guest" account access has inherent security risks and should be disabled. To do disable
timed logins or guest account access, set the TimedLoginEnable to false in
the [daemon] section in /etc/gdm/custom.conf. For example:
[daemon]
TimedLoginEnable=false
            

SSH environment options potentially allow users to bypass
access restriction in some configurations.

To determine how the SSH daemon's PermitUserEnvironment option is set, run the following command:

$ sudo grep -i PermitUserEnvironment /etc/ssh/sshd_config

If a line indicating no is returned, then the required value is set.

      Is it the case that the required value is not set?
      

Ensure that users are not able to override environment variables of the SSH daemon.

The default SSH configuration disables environment processing. The appropriate
configuration is used if no value is set for PermitUserEnvironment.

To explicitly disable Environment options, add or correct the following


/etc/ssh/sshd_config:

PermitUserEnvironment no
          

SSH trust relationships mean a compromise on one host
can allow an attacker to move trivially to other hosts.

To determine how the SSH daemon's HostbasedAuthentication option is set, run the following command:

$ sudo grep -i HostbasedAuthentication /etc/ssh/sshd_config

If a line indicating no is returned, then the required value is set.

      Is it the case that the required value is not set?
      

SSH's cryptographic host-based authentication is
more secure than .rhosts authentication. However, it is
not recommended that hosts unilaterally trust one another, even
within an organization.

The default SSH configuration disables host-based authentication. The appropriate
configuration is used if no value is set for HostbasedAuthentication.

To explicitly disable host-based authentication, add or correct the
following line in


/etc/ssh/sshd_config:

HostbasedAuthentication no
          

This prevents attackers with physical access from trivially bypassing security
on the machine and gaining root access. Such accesses are further prevented
by configuring the bootloader password.

To check if authentication is required for single-user mode, run the following command:
$ grep sulogin /usr/lib/systemd/system/rescue.service
The output should be similar to the following, and the line must begin with
ExecStart and /sbin/sulogin.
    ExecStart=-/bin/sh -c "/sbin/sulogin; /usr/bin/systemctl --fail --no-block default"


Then, verify that the rescue service is in the runlevel1.target.
Run the following command:
$ sudo grep "^Requires=.*rescue\.service" /usr/lib/systemd/system/runlevel1.target
The output should be the following:
Requires=sysinit.target rescue.service

Then, check if there is no custom runlevel1 target configured in systemd configuration.
Run the following command:
$ sudo grep -r "^runlevel1.target$" /etc/systemd/system
There should be no output.

Then, check if there is no custom rescue service configured in systemd configuration.
Run the following command:
$ sudo grep -r "^rescue.service$" /etc/systemd/system
There should be no output.
      Is it the case that the output is different?
      

Single-user mode is intended as a system recovery
method, providing a single user root access to the system by
providing a boot option at startup.

            
By default, single-user mode is protected by requiring a password and is set
in /usr/lib/systemd/system/rescue.service.

Password protection on the boot loader configuration ensures
users with physical access cannot trivially alter
important bootloader settings. These include which kernel to use,
and whether to enter single-user mode.

First, check whether the password is defined in either /boot/grub2/user.cfg or
/boot/grub2/grub.cfg.
Run the following commands:
$ sudo grep '^[\s]*GRUB2_PASSWORD=grub\.pbkdf2\.sha512.*$' /boot/grub2/user.cfg
$ sudo grep '^[\s]*password_pbkdf2[\s]+.*[\s]+grub\.pbkdf2\.sha512.*$' /boot/grub2/grub.cfg


Second, check that a superuser is defined in /boot/grub2/grub.cfg.
$ sudo grep '^[\s]*set[\s]+superusers=("?)[a-zA-Z_]+\1$'  /boot/grub2/grub.cfg
      Is it the case that it does not produce any output?
      

The grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.

            
Since plaintext passwords are a security risk, generate a hash for the password
by running the following command:

# grub2-setpassword

When prompted, enter the password that was selected.

            
          

Having a non-default grub superuser username makes password-guessing attacks less effective.

To verify the boot loader superuser account has been set, run the following
command:
sudo grep -A1 "superusers" /boot/grub2/grub.cfg
The output should show the following:
set superusers="superusers-account"
export superusers
where superusers-account is the actual account name different from common names like root,
admin, or administrator and different from any other existing user name.
      Is it the case that superuser account is not set or is set to root, admin, administrator or any other existing user name?
      

The grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.

            
To maximize the protection, select a password-protected superuser account with unique name, and modify the
/etc/grub.d/01_users configuration file to reflect the account name change.

            
Do not to use common administrator account names like root,
admin, or administrator for the grub2 superuser account.

            
Change the superuser to a different username (The default is 'root').
$ sed -i 's/\(set superusers=\).*/\1""/g' /etc/grub.d/01_users
            
            
Once the superuser account has been added,
update the
grub.cfg file by running:
grubby --update-kernel=ALL
          

Password protection on the boot loader configuration ensures
users with physical access cannot trivially alter
important bootloader settings. These include which kernel to use,
and whether to enter single-user mode.

To verify the boot loader superuser password has been set, run the following command:
$ sudo grep "^[\s]*GRUB2_PASSWORD=grub\.pbkdf2\.sha512.*$" /boot/efi/EFI/redhat/user.cfg
The output should be similar to:
GRUB2_PASSWORD=grub.pbkdf2.sha512.10000.C4E08AC72FBFF7E837FD267BFAD7AEB3D42DDC
2C99F2A94DD5E2E75C2DC331B719FE55D9411745F82D1B6CFD9E927D61925F9BBDD1CFAA0080E0
916F7AB46E0D.1302284FCCC52CD73BA3671C6C12C26FF50BA873293B24EE2A96EE3B57963E6D7
0C83964B473EC8F93B07FE749AA6710269E904A9B08A6BBACB00A2D242AD828
      Is it the case that no password is set?
      

The grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.

            
Since plaintext passwords are a security risk, generate a hash for the password
by running the following command:

# grub2-setpassword

When prompted, enter the password that was selected.

            
          

Having a non-default grub superuser username makes password-guessing attacks less effective.

To verify the boot loader superuser account has been set, run the following
command:
sudo grep -A1 "superusers" /boot/efi/EFI/redhat/grub.cfg
The output should show the following:
set superusers="superusers-account"
export superusers
where superusers-account is the actual account name different from common names like root,
admin, or administrator and different from any other existing user name.
      Is it the case that superuser account is not set or is set to an existing name or to a common name?
      

The grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.

            
To maximize the protection, select a password-protected superuser account with unique name, and modify the
/etc/grub.d/01_users configuration file to reflect the account name change.

            
It is highly suggested not to use common administrator account names like root,
admin, or administrator for the grub2 superuser account.

            
Change the superuser to a different username (The default is 'root').
$ sed -i 's/\(set superusers=\).*/\1""/g' /etc/grub.d/01_users
            
            
Once the superuser account has been added,
update the
grub.cfg file by running:
grubby --update-kernel=ALL
          

Smart card login provides two-factor authentication stronger than
that provided by a username and password combination. Smart cards leverage PKI
(public key infrastructure) in order to provide and verify credentials.

Interview the SA to determine if all accounts not exempted by policy are
using CAC authentication. For DoD systems, the following systems and
accounts are exempt from using smart card (CAC) authentication:

SIPRNET systems
Standalone systems
Application accounts
Temporary employee accounts, such as students or interns, who cannot
easily receive a CAC or PIV
Operational tactical locations that are not collocated with RAPIDS
workstations to issue CAC or ALT
Test systems, such as those with an Interim Approval to Test (IATT) and
use a separate VPN, firewall, or security measure preventing access to
network and system components from outside the protection boundary
documented in the IATT.

      Is it the case that non-exempt accounts are not using CAC authentication?
      

To enable smart card authentication, consult the documentation at:

                  
                    
                      https://docs.oracle.com/en/operating-systems/oracle-linux/7/userauth/userauth-AuthenticationConfiguration.html#ol7-s4-auth
                    
                  
                
              

The rsh-server service provides unencrypted remote access service which does not
provide for the confidentiality and integrity of user passwords or the remote session and has very weak
authentication. If a privileged user were to login using this service, the privileged user password
could be compromised. The rsh-server package provides several obsolete and insecure
network services. Removing it decreases the risk of those services' accidental (or intentional)
activation.

Run the following command to determine if the rsh-server package is installed:
$ rpm -q rsh-server
      Is it the case that the package is installed?
      

The rsh-server package can be removed with the following command:

$ sudo yum erase rsh-server
          

The NIS service provides an unencrypted authentication service which does
not provide for the confidentiality and integrity of user passwords or the
remote session.

Removing the ypserv package decreases the risk of the accidental
(or intentional) activation of NIS or NIS+ services.

Run the following command to determine if the ypserv package is installed:
$ rpm -q ypserv
      Is it the case that the package is installed?
      

The ypserv package can be removed with the following command:

$ sudo yum erase ypserv
          

Preventing non-privileged users from executing privileged functions mitigates
the risk that unauthorized individuals or processes may gain unnecessary access
to information or privileges.

          
Privileged functions include, for example,
establishing accounts, performing system integrity checks, or administering
cryptographic key management activities. Non-privileged users are individuals
who do not possess appropriate authorizations. Circumventing intrusion detection
and prevention mechanisms or malicious code protection mechanisms are examples
of privileged functions that require protection from non-privileged users.

To verify the operating system prevents non-privileged users from executing
privileged functions to include disabling, circumventing, or altering
implemented security safeguards/countermeasures, run the following
command:
$ sudo semanage login -l
All administrators must be mapped to the sysadm_u or staff_u
users with the appropriate domains (sysadm_t and staff_t).

All authorized non-administrative
users must be mapped to the user_u role or the appropriate domain
(user_t).
      Is it the case that non-admin users are not confined correctly?
      

Configure the operating system to prevent non-privileged users from executing
privileged functions to include disabling, circumventing, or altering
implemented security safeguards/countermeasures. All administrators must be
mapped to the sysadm_u or staff_u users with the
appropriate domains (sysadm_t and staff_t).
$ sudo semanage login -m -s sysadm_u USER
           or
$ sudo semanage login -m -s staff_u USER
          
          
          
All authorized non-administrative
users must be mapped to the user_u role or the appropriate domain
(user_t).
$ sudo semanage login -m -s user_u USER
          
        

Preventing non-privileged users from executing privileged functions mitigates
the risk that unauthorized individuals or processes may gain unnecessary access
to information or privileges.

          
Privileged functions include, for example,
establishing accounts, performing system integrity checks, or administering
cryptographic key management activities. Non-privileged users are individuals
who do not possess appropriate authorizations. Circumventing intrusion detection
and prevention mechanisms or malicious code protection mechanisms are examples
of privileged functions that require protection from non-privileged users.

Verify the operating system confines SELinux users to roles that conform to least
privilege. Check the SELinux User list to SELinux Roles mapping by using the
following command:
sudo semanage user -l
The output should look like this:
SELinuxUser LabelingPrefix MLS/MCSLevel MLS/MCSRange SELinuxRoles
guest_u            user  s0  s0  guest_r
root                   user  s0  s0-s0:c0.c1023  staff_r sysadm_r system_r unconfined_r
staff_u              user  s0  s0-s0:c0.c1023  staff_r sysadm_r
sysadm_u         user  s0  s0-s0:c0.c1023  sysadm_r
system_u          user  s0  s0-s0:c0.c1023  system_r unconfined_r
unconfined_u  user  s0  s0-s0:c0.c1023  system_r unconfined_r
user_u               user  s0  s0  user_r
xguest_u           user  s0  s0  xguest_r

      Is it the case that selinux users are not confined to least privilege?
      

Configure the operating system to confine SELinux users to roles that conform
to least privilege. Use the following command to map the "staff_u" SELinux user
to the "staff_r" and "sysadm_r" roles:
$ sudo semanage user -m staff_u -R staff_r -R sysadm_r
          
          
Use the following command to map the "user_u" SELinux user to the "user_r" role:
$ sudo semanage -m user_u -R user_r
        

Preventing non-privileged users from executing privileged functions mitigates
the risk that unauthorized individuals or processes may gain unnecessary access
to information or privileges.

Privileged functions include, for example, establishing accounts, performing
system integrity checks, or administering cryptographic key management
activities. Non-privileged users are individuals who do not possess appropriate
authorizations. Circumventing intrusion detection and prevention mechanisms or
malicious code protection mechanisms are examples of privileged functions that
require protection from non-privileged users.

Run the following command to determine if the ssh_sysadm_login SELinux boolean is disabled:
$ getsebool ssh_sysadm_login
If properly configured, the output should show the following:
ssh_sysadm_login --> off
      Is it the case that ssh_sysadm_login is not disabled?
      

By default, the SELinux boolean ssh_sysadm_login is disabled.
If this setting is enabled, it should be disabled.

To disable the ssh_sysadm_login SELinux boolean, run the following command:
$ sudo setsebool -P ssh_sysadm_login off
          

Preventing non-privileged users from executing privileged functions mitigates
the risk that unauthorized individuals or processes may gain unnecessary access
to information or privileges.

          
Privileged functions include, for example,
establishing accounts, performing system integrity checks, or administering
cryptographic key management activities. Non-privileged users are individuals
who do not possess appropriate authorizations. Circumventing intrusion detection
and prevention mechanisms or malicious code protection mechanisms are examples
of privileged functions that require protection from non-privileged users.

Verify the operating system elevates the SELinux context when an administrator calls the
sudo command with the following command:

This command must be ran as root:
grep sysadm_r /etc/sudoers.d/*
%wheel ALL=(ALL) TYPE=sysadm_t ROLE=sysadm_r ALL

      Is it the case that selinux context does not elevate when running sudo command?
      

Configure the operating system to elevate the SELinux context when an administrator calls
the sudo command.
Edit a file in the /etc/sudoers.d directory with the following command:
sudo visudo -f /etc/sudoers.d/CUSTOM_FILE
          
Use the following example to build the CUSTOM_FILE in the /etc/sudoers.d directory
to allow any administrator belonging to a designated sudoers admin group to elevate their
SELinux context with the use of the sudo command:
%wheel ALL=(ALL) TYPE=sysadm_t ROLE=sysadm_r ALL
        

Emails can be used to notify designated personnel about important
system events such as failures or warnings.

Run the following command to determine if the mailx package is installed: $ rpm -q mailx
      Is it the case that the package is not installed?
      

A mail server is required for sending emails.
The mailx package can be installed with the following command:

$ sudo yum install mailx
        

For AIDE to be effective, an initial database of "known-good" information about files
must be captured and it should be able to be verified against the installed files.

To find the location of the AIDE database file, run the following command:
$ sudo ls -l DBDIR/database_file_name
      Is it the case that there is no database file?
      

Run the following command to generate a new database:

$ sudo /usr/sbin/aide --init

By default, the database will be written to the file

/var/lib/aide/aide.db.new.gz.

Storing the database, the configuration file /etc/aide.conf, and the binary
/usr/sbin/aide
(or hashes of these files), in a secure location (such as on read-only media) provides additional assurance about their integrity.
The newly-generated database can be installed as follows:

$ sudo cp /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz

To initiate a manual check, run the following command:
$ sudo /usr/sbin/aide --check
If this check produces any unexpected output, investigate.

By default, AIDE does not install itself for periodic execution. Periodically
running AIDE is necessary to reveal unexpected changes in installed files.

                
Unauthorized changes to the baseline configuration could make the system vulnerable
to various attacks or allow unauthorized access to the operating system. Changes to
operating system configurations can have unintended side effects, some of which may
be relevant to security.

                
Detecting such changes and providing an automated response can help avoid unintended,
negative consequences that could ultimately affect the security state of the operating
system. The operating system's Information Management Officer (IMO)/Information System
Security Officer (ISSO) and System Administrators (SAs) must be notified via email and/or
monitoring system trap when there is an unauthorized modification of a configuration item.

Verify the operating system routinely checks the baseline configuration for unauthorized changes.

To determine that periodic AIDE execution has been scheduled, run the following command:
$ grep aide /etc/crontab
The output should return something similar to the following:
05 4 * * * root /usr/sbin/aide --check

NOTE: The usage of special cron times, such as @daily or @weekly, is acceptable.
      Is it the case that AIDE is not configured to scan periodically?
      

At a minimum, AIDE should be configured to run a weekly scan.
To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab:
05 4 * * * root /usr/sbin/aide --check
To implement a weekly execution of AIDE at 4:05am using cron, add the following line to /etc/crontab:
05 4 * * 0 root /usr/sbin/aide --check
AIDE can be executed periodically through other means; this is merely one example.
The usage of cron's special time codes, such as  @daily and
@weekly is acceptable.

Unauthorized changes to the baseline configuration could make the system vulnerable
to various attacks or allow unauthorized access to the operating system. Changes to
operating system configurations can have unintended side effects, some of which may
be relevant to security.

                
Detecting such changes and providing an automated response can help avoid unintended,
negative consequences that could ultimately affect the security state of the operating
system. The operating system's Information Management Officer (IMO)/Information System
Security Officer (ISSO) and System Administrators (SAs) must be notified via email and/or
monitoring system trap when there is an unauthorized modification of a configuration item.

To determine that periodic AIDE execution has been scheduled, run the following command:

$ grep aide /etc/crontab
The output should return something similar to the following:
05 4 * * * root /usr/sbin/aide --check | /bin/mail -s "$(hostname) - AIDE Integrity Check" root@localhost
The email address that the notifications are sent to can be changed by overriding
.
      Is it the case that AIDE has not been configured or has not been configured to notify personnel of scan details?
      

AIDE should notify appropriate personnel of the details of a scan after the scan has been run.
If AIDE has already been configured for periodic execution in /etc/crontab, append the
following line to the existing AIDE line:
 | /bin/mail -s "$(hostname) - AIDE Integrity Check" root@localhost
Otherwise, add the following line to /etc/crontab:
05 4 * * * root /usr/sbin/aide --check | /bin/mail -s "$(hostname) - AIDE Integrity Check" root@localhost
AIDE can be executed periodically through other means; this is merely one example.

Changes to any 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.

Accordingly, patches, service packs, device drivers, or operating system
components must be signed with a certificate recognized and approved by the
organization.
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).

Verify that yum verifies the signature of packages from a repository prior to install with the following command:

$ grep gpgcheck /etc/yum.conf

gpgcheck=1

If "gpgcheck" is not set to "1", or if the option is missing or commented out, ask the System Administrator how the certificates for patches and other operating system components are verified.
      Is it the case that there is no process to validate certificates that is approved by the organization?
      

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
          

Changes to any software components can have significant effects to the overall security
of the operating system. This requirement ensures the software has not been tampered and
has been provided by a trusted vendor.

            
Accordingly, patches, service packs, device drivers, or operating system components must
be signed with a certificate recognized and approved by the organization.

Verify that yum verifies the signature of local packages prior to install with the following command:

$ grep localpkg_gpgcheck /etc/yum.conf

localpkg_gpgcheck=1

If "localpkg_gpgcheck" is not set to "1", or if the option is missing or commented out, ask the System Administrator how the certificates for patches and other operating system components are verified.
      Is it the case that there is no process to validate certificates for local packages that is approved by the organization?
      

            yum should be configured to verify the signature(s) of local packages
prior to installation. To configure yum to verify signatures of local
packages, set the localpkg_gpgcheck to 1 in /etc/yum.conf.

USB storage devices such as thumb drives can be used to introduce
malicious software.

If the system is configured to prevent the loading of the usb-storage kernel module,
it will contain lines inside any file in /etc/modprobe.d or the deprecated /etc/modprobe.conf.
These lines instruct the module loading system to run another program (such as /bin/false) upon a module install event.

These lines can also instruct the module loading system to ignore the usb-storage kernel module via blacklist keyword.

Run the following command to search for such lines in all files in /etc/modprobe.d and the deprecated /etc/modprobe.conf:
$ grep -r usb-storage /etc/modprobe.conf /etc/modprobe.d
      Is it the case that no line is returned?
      

To prevent USB storage devices from being used, configure the kernel module loading system
to prevent automatic loading of the USB storage driver.

To configure the system to prevent the usb-storage
kernel module from being loaded, add the following line to the file /etc/modprobe.d/usb-storage.conf:
install usb-storage /bin/false

To configure the system to prevent the usb-storage from being used,
add the following line to file /etc/modprobe.d/usb-storage.conf:
blacklist usb-storage

This will prevent the modprobe program from loading the usb-storage
module, but will not prevent an administrator (or another program) from using the
insmod program to load the module manually.

Disabling DCCP protects
the system against exploitation of any flaws in its implementation.

If the system is configured to prevent the loading of the dccp kernel module,
it will contain lines inside any file in /etc/modprobe.d or the deprecated /etc/modprobe.conf.
These lines instruct the module loading system to run another program (such as /bin/false) upon a module install event.

These lines can also instruct the module loading system to ignore the dccp kernel module via blacklist keyword.

Run the following command to search for such lines in all files in /etc/modprobe.d and the deprecated /etc/modprobe.conf:
$ grep -r dccp /etc/modprobe.conf /etc/modprobe.d
      Is it the case that no line is returned?
      

The Datagram Congestion Control Protocol (DCCP) is a
relatively new transport layer protocol, designed to support
streaming media and telephony.

To configure the system to prevent the dccp
kernel module from being loaded, add the following line to the file /etc/modprobe.d/dccp.conf:
install dccp /bin/false

To configure the system to prevent the dccp from being used,
add the following line to file /etc/modprobe.d/dccp.conf:
blacklist dccp
          

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

            
Additionally, automatically mounting filesystems permits easy introduction of
unknown devices, thereby facilitating malicious activity.

To check that the autofs service is disabled in system boot configuration,
run the following command:
$ sudo systemctl is-enabled autofs
Output should indicate the autofs service has either not been installed,
or has been disabled at all runlevels, as shown in the example below:
$ sudo systemctl is-enabled autofs disabled

Run the following command to verify autofs is not active (i.e. not running) through current runtime configuration:
$ sudo systemctl is-active autofs

If the service is not running the command will return the following output:
inactive

The service will also be masked, to check that the autofs is masked, run the following command:
$ sudo systemctl show autofs | grep "LoadState\|UnitFileState"

If the service is masked the command will return the following outputs:

LoadState=masked

UnitFileState=masked
      Is it the case that the "autofs" is loaded and not masked?
      

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 mask --now autofs.service
          

Automatically mounting file systems permits easy introduction of unknown devices, thereby facilitating malicious activity.
Disabling automatic mount running in GNOME3 can prevent
the introduction of malware via removable media.
It will, however, also prevent desktop users from legitimate use
of removable media.

These settings can be verified by running the following:
$ gsettings get org.gnome.desktop.media-handling autorun-never
If properly configured, the output for autorun-nevershould be true.
To ensure that users cannot enable autorun in GNOME3, run the following:
$ grep 'autorun-never' /etc/dconf/db/local.d/locks/*
If properly configured, the output for autorun-never should be /org/gnome/desktop/media-handling/autorun-never
      Is it the case that GNOME autorun is not disabled?
      

The system's default desktop environment, GNOME3, will mount
devices and removable media (such as DVDs, CDs and USB flash drives) whenever
they are inserted into the system. To disable autorun-never within GNOME3, add or set
autorun-never to true in /etc/dconf/db/local.d/00-security-settings.
For example:
[org/gnome/desktop/media-handling]
autorun-never=true
Once the settings have been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/desktop/media-handling/autorun-never
After the settings have been set, run dconf update.

Previous versions of software components that are not removed from the information
system after updates have been installed may be exploited by some adversaries.

Verify Oracle Linux 7 removes all software components after updated versions have been installed.


$ grep clean_requirements_on_remove /etc/yum.conf
clean_requirements_on_remove=1
      Is it the case that '"clean_requirements_on_remove" is not set to "1"'?
      

            yum should be configured to remove previous software components after
new versions have been installed. To configure yum to remove the

previous software components after updating, set the clean_requirements_on_remove


to 1 in /etc/yum.conf.

Setting the SELinux state to enforcing ensures SELinux is able to confine
potentially compromised processes to the security policy, which is designed to
prevent them from causing damage to the system or further elevating their
privileges.

Ensure that Oracle Linux 7 verifies correct operation of security functions.

Check if "SELinux" is active and in "" mode with the following command:

$ sudo getenforce

      Is it the case that SELINUX is not set to enforcing?
      

The SELinux state should be set to 
            
           at
system boot time.  In the file /etc/selinux/config, add or correct the
following line to configure the system to boot into enforcing mode:
SELINUX=
          
        

Setting the SELinux policy to targeted or a more specialized policy
ensures the system will confine processes that are likely to be
targeted for exploitation, such as network or system services.

          
Note: During the development or debugging of SELinux modules, it is common to
temporarily place non-production systems in permissive mode. In such
temporary cases, SELinux policies should be developed, and once work
is completed, the system should be reconfigured to

            
          .

Verify the SELINUX on Oracle Linux 7 is using the  policy with the following command:

$ sestatus | grep policy

Loaded policy name:             
      Is it the case that the loaded policy name is not ""?
      

The SELinux targeted policy is appropriate for
general-purpose desktops and servers, as well as systems in many other roles.
To configure the system to use this policy, add or correct the following line
in /etc/selinux/config:
SELINUXTYPE=
          
Other policies, such as mls, provide additional security labeling
and greater confinement but are not compatible with many general-purpose
use cases.

A locally logged-in user who presses Ctrl-Alt-Del, when at the console,
can reboot the system. If accidentally pressed, as could happen in
the case of mixed OS environment, this can create the risk of short-term
loss of availability of systems due to unintentional reboot.

To ensure the system is configured to mask the Ctrl-Alt-Del sequence, Check
that the ctrl-alt-del.target is masked and not active with the following
command:
sudo systemctl status ctrl-alt-del.target
The output should indicate that the target is masked and not active. It
might resemble following output:
ctrl-alt-del.target
Loaded: masked (/dev/null; bad)
Active: inactive (dead)
      Is it the case that the system is configured to reboot when Ctrl-Alt-Del is pressed?
      

By default, SystemD will reboot the system if the Ctrl-Alt-Del
key sequence is pressed.

            
To configure the system to ignore the Ctrl-Alt-Del key sequence from the

command line instead of rebooting the system, do either of the following:
ln -sf /dev/null /etc/systemd/system/ctrl-alt-del.target
or
systemctl mask ctrl-alt-del.target
            
            
Do not simply delete the /usr/lib/systemd/system/ctrl-alt-del.service file,
as this file may be restored during future system updates.

A locally logged-in user who presses Ctrl-Alt-Del, when at the console,
can reboot the system. If accidentally pressed, as could happen in
the case of mixed OS environment, this can create the risk of short-term
loss of availability of systems due to unintentional reboot.

To ensure the system is configured to ignore the Ctrl-Alt-Del sequence,
run the following command:
$ gsettings get org.gnome.settings-daemon.plugins.media-keys logout
$ grep logout /etc/dconf/db/local.d/locks/*
If properly configured, the output should be
/org/gnome/settings-daemon/plugins/media-keys/logout
      Is it the case that GNOME3 is configured to reboot when Ctrl-Alt-Del is pressed?
      

By default, GNOME will reboot the system if the
Ctrl-Alt-Del key sequence is pressed.

              
To configure the system to ignore the Ctrl-Alt-Del key sequence
from the Graphical User Interface (GUI) instead of rebooting the system,
add or set logout to [''] in
/etc/dconf/db/local.d/00-security-settings. For example:
[org/gnome/settings-daemon/plugins/media-keys]
logout=['']
Once the settings have been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent
user modification. For example:
/org/gnome/settings-daemon/plugins/media-keys/logout
After the settings have been set, run dconf update.

The umask value influences the permissions assigned to files when they are created.
A misconfigured umask value could result in files with excessive permissions that can be read and
written to by unauthorized users.

Verify Oracle Linux 7 defines default permissions for all authenticated users in such a way that the user can only read and modify their own files with the following command:

# grep -i umask /etc/login.defs

UMASK 
      Is it the case that the value for the "UMASK" parameter is not "", or the "UMASK" parameter is missing or is commented out?
      

To ensure the default umask controlled by /etc/login.defs is set properly,
add or correct the UMASK setting in /etc/login.defs to read as follows:
UMASK 
              
            

An operating system is considered "supported" if the vendor continues to
provide security patches for the product.  With an unsupported release, it
will not be possible to resolve any security issue discovered in the system
software.

To verify that the installed operating system is supported, run
the following command:

$ grep -i "oracle" /etc/oracle-release

Oracle Linux 7
      Is it the case that the installed operating system is not supported?
      

The installed operating system must be maintained by a vendor.

Oracle Linux is supported by Oracle Corporation. As the Oracle
Linux vendor, Oracle Corporation is responsible for providing security patches.

Installing software updates is a fundamental mitigation against
the exploitation of publicly-known vulnerabilities. If the most
recent security patches and updates are not installed, unauthorized
users may take advantage of weaknesses in the unpatched software. The
lack of prompt attention to patching could result in a system compromise.

If the system is joined to the ULN
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 ULN and installed using rpm.


            
NOTE: U.S. Defense systems are required to be patched within 30 days or sooner as local policy
dictates.

Accounts providing no operational purpose provide additional opportunities for
system compromise. Unnecessary accounts include user accounts for individuals not
requiring access to the system and application accounts for applications not installed
on the system.

To verify that there are no unauthorized local user accounts, run the following command:
$ less /etc/passwd 
Inspect the results, and if unauthorized local user accounts exist, remove them by running
the following command:
$ sudo userdel unauthorized_user
      Is it the case that there are unauthorized local user accounts on the system?
      

Enterprise Application tends to use the server or virtual machine exclusively.
Besides the default operating system user, there should be only authorized local
users required by the installed software groups and applications that exist on
the operating system. The authorized user list can be customized in the refine
value variable var_accounts_authorized_local_users_regex.
OVAL regular expression is used for the user list.
Configure the system so all accounts on the system are assigned to an active system,
application, or user account. Remove accounts that do not support approved system
activities or that allow for a normal user to perform administrative-level actions.
To remove unauthorized system accounts, use the following command:
$ sudo userdel unauthorized_user
            
          

If a user is assigned the Group Identifier (GID) of a group not existing on the system, and a group
with the Group Identifier (GID) is subsequently created, the user may have unintended rights to
any files associated with the group.

To ensure all GIDs referenced in /etc/passwd are defined in /etc/group,
run the following command:
$ sudo pwck -qr
There should be no output.
      Is it the case that GIDs referenced in /etc/passwd are returned as not defined in /etc/group?
      

Add a group to the system for each GID referenced without a corresponding group.

An account has root authority if it has a UID of 0. Multiple accounts
with a UID of 0 afford more opportunity for potential intruders to
guess a password for a privileged account. Proper configuration of
sudo is recommended to afford multiple system administrators
access to root privileges in an accountable manner.

Verify that only the "root" account has a UID "0" assignment with the
following command:
$ awk -F: '$3 == 0 {print $1}' /etc/passwd
root
      Is it the case that any accounts other than "root" have a UID of "0"?
      

If any account other than root has a UID of 0, this misconfiguration should
be investigated and the accounts other than root should be removed or have
their UID changed.

If the account is associated with system commands or applications the UID
should be changed to one greater than "0" but less than "1000."
Otherwise assign a UID greater than "1000" that has not already been
assigned.

Unowned files do not directly imply a security problem, but they are generally a sign that
something is amiss. They may be caused by an intruder, by incorrect software installation or
draft software removal, or by failure to remove all files belonging to a deleted account, or
other similar cases. The files should be repaired so they will not cause problems when
accounts are created in the future, and the cause should be discovered and addressed.

The following command will locate the mount points related to local devices:
$ findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)

The following command will show files which do not belong to a valid user:
$ sudo find MOUNTPOINT -xdev -nouser 2>/dev/null

Replace MOUNTPOINT by the mount points listed by the fist command.

No files without a valid user should be located.
      Is it the case that files exist that are not owned by a valid user?
      

If any files are not owned by a user, then the cause of their lack of ownership should be
investigated. Following this, the files should be deleted or assigned to an appropriate user.

Locate the mount points related to local devices by the following command:
$ findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)

For all mount points listed by the previous command, it is necessary to search for files which
do not belong to a valid user using the following command:
$ sudo find MOUNTPOINT -xdev -nouser 2>/dev/null
          

Unowned files do not directly imply a security problem, but they are generally a sign that
something is amiss. They may be caused by an intruder, by incorrect software installation or
draft software removal, or by failure to remove all files belonging to a deleted account, or
other similar cases. The files should be repaired so they will not cause problems when
accounts are created in the future, and the cause should be discovered and addressed.

The following command will locate the mount points related to local devices:
$ findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)

The following command will show files which do not belong to a valid group:
$ sudo find MOUNTPOINT -xdev -nogroup 2>/dev/null

Replace MOUNTPOINT by the mount points listed by the fist command.

No files without a valid group should be located.
      Is it the case that there is output?
      

If any file is not group-owned by a group present in /etc/group, the cause of the lack of
group-ownership must be investigated. Following this, those files should be deleted or
assigned to an appropriate group.

Locate the mount points related to local devices by the following command:
$ findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)

For all mount points listed by the previous command, it is necessary to search for files which
do not belong to a valid group using the following command:
$ sudo find MOUNTPOINT -xdev -nogroup 2>/dev/null
          

If local interactive users are not assigned a valid home directory, there is no place
for the storage and control of files they should own.

Verify all local interactive users on Oracle Linux 7 are assigned a home
directory upon creation with the following command:
$ grep -i create_home /etc/login.defs
CREATE_HOME yes
      Is it the case that the value for "CREATE_HOME" parameter is not set to "yes", the line is missing, or the line is commented out?
      

All local interactive user accounts, upon creation, should be assigned a home directory.

            
Configure the operating system to assign home directories to all new local interactive users by setting the CREATE_HOME
parameter in /etc/login.defs to yes as follows:

            
            CREATE_HOME yes
          

If a local interactive user has a home directory defined that does not exist,
the user may be given access to the / directory as the current working directory
upon logon. This could create a Denial of Service because the user would not be
able to access their logon configuration files, and it may give them visibility
to system files they normally would not be able to access.

Verify the assigned home directories of all interactive users on the system exist with the following command:

$ sudo pwck -r

user 'mailnull': directory 'var/spool/mqueue' does not exist

The output should not return any interactive users.
      Is it the case that users home directory does not exist?
      

Create home directories to all local interactive users that currently do not
have a home directory assigned. Use the following commands to create the user
home directory assigned in /etc/passwd:
$ sudo mkdir /home/USER
            
          

Excessive permissions on local interactive user home directories may allow
unauthorized access to user files by other users.

To verify the assigned home directory of all interactive user home directories
have a mode of 0750 or less permissive, run the following command:
$ sudo ls -l /home
Inspect the output for any directories with incorrect permissions.
      Is it the case that they are more permissive?
      

Change the mode of interactive users home directories to 0750. To
change the mode of interactive users home directory, use the
following command:
$ sudo chmod 0750 /home/USER
            
          

If a local interactive user does not own their home directory, unauthorized
users could access or modify the user's files, and the users may not be able to
access their own files.

To verify the home directory ownership, run the following command:
# ls -ld $(awk -F: '($3>=1000)&&($7 !~ /nologin/){print $6}' /etc/passwd)
      Is it the case that the user ownership is incorrect?
      

Change the owner of interactive users home directories to that correct
owner. To change the owner of a interactive users home directory, use
the following command:
$ sudo chown USER /home/USER
            

This rule ensures every home directory related to an interactive user is
owned by an interactive user. It also ensures that interactive users are
owners of one and only one home directory.

If the Group Identifier (GID) of a local interactive users home directory is
not the same as the primary GID of the user, this would allow unauthorized
access to the users files, and users that share the same group may not be
able to access files that they legitimately should.

To verify the assigned home directory of all interactive users is group-
owned by that users primary GID, run the following command:
# ls -ld $(awk -F: '($3>=1000)&&($7 !~ /nologin/){print $6}' /etc/passwd)
      Is it the case that the group ownership is incorrect?
      

Change the group owner of interactive users home directory to the
group found in /etc/passwd. To change the group owner of
interactive users home directory, use the following command:
$ sudo chgrp USER_GROUP /home/USER
            

This rule ensures every home directory related to an interactive user is
group-owned by an interactive user. It also ensures that interactive users
are group-owners of one and only one home directory.

If local interactive users do not own the files in their directories,
unauthorized users may be able to access them. Additionally, if files are not
owned by the user, this could be an indication of system compromise.

To verify all files and directories in a local interactive user's
home directory have a valid owner, run the following command:
$ sudo ls -lLR /home/USER
      Is it the case that the user ownership is incorrect?
      

Either remove all files and directories from the system that
do not have a valid user, or assign a valid user to all unowned
files and directories. To assign a valid owner to a local
interactive user's files and directories, use the following command:
$ sudo chown -R USER /home/USER
            

This rule ensures every file or directory under the home directory related
to an interactive user is owned by an interactive user.

If a local interactive users files are group-owned by a group of which the
user is not a member, unintended users may be able to access them.

To verify all files and directories in interactive user home directory are
group-owned by a group the user is a member of, run the
following command:
$ sudo ls -lLR /home/USER
      Is it the case that the group ownership is incorrect?
      

Change the group of a local interactive users files and directories to a
group that the interactive user is a member of. To change the group owner of a
local interactive users files and directories, use the following command:
$ sudo chgrp USER_GROUP /home/USER/FILE_DIR
            

This rule ensures every file or directory under the home directory related
to an interactive user is group-owned by an interactive user.

If a local interactive user files have excessive permissions, unintended users
may be able to access or modify them.

To verify all files and directories contained in interactive user home
directory, excluding local initialization files, have a mode of 0750,
run the following command:
$ sudo ls -lLR /home/USER
      Is it the case that home directory files or folders have incorrect permissions?
      

Set the mode on files and directories in the local interactive user home
directory with the following command:
$ sudo chmod 0750 /home/USER/FILE_DIR
            
Files that begin with a "." are excluded from this requirement.

Local initialization files are used to configure the user's shell environment
upon logon. Malicious modification of these files could compromise accounts upon
logon.

To verify all local initialization files for interactive users are owned by the
primary user, run the following command:
$ sudo ls -al /home/USER/.*
The user initialization files should be owned by USER.
      Is it the case that they are not?
      

Set the owner of the user initialization files for interactive users to
the primary owner with the following command:
$ sudo chown USER /home/USER/.*

This rule ensures every initialization file related to an interactive user
is owned by an interactive user.

Local initialization files for interactive users are used to configure the
user's shell environment upon logon. Malicious modification of these files could
compromise accounts upon logon.

To verify the local initialization files of all local interactive users are group-
owned by the appropriate user, inspect the primary group of the respective
users in /etc/passwd and verify all initialization files under the
respective users home directory. Check the group owner of all local interactive users
initialization files.
      Is it the case that they are not?
      

Change the group owner of interactive users files to the group found
in /etc/passwd for the user. To change the group owner of a local
interactive user home directory, use the following command:
$ sudo chgrp USER_GROUP /home/USER/.INIT_FILE
            

This rule ensures every initialization file related to an interactive user
is group-owned by an interactive user.

Local initialization files are used to configure the user's shell environment
upon logon. Malicious modification of these files could compromise accounts upon
logon.

To verify that all user initialization files have a mode of 0740 or
less permissive, run the following command:
$ sudo find /home -type f -name '\.*' \( -perm -0002 -o -perm -0020 \)
There should be no output.
      Is it the case that they are not 0740 or more permissive?
      

Set the mode of the user initialization files to 0740 with the
following command:
$ sudo chmod 0740 /home/USER/.INIT_FILE
            
          

The executable search path (typically the PATH environment variable) contains a
list of directories for the shell to search to find executables. If this path
includes the current working directory (other than the users home directory),
executables in these directories may be executed instead of system commands.
This variable is formatted as a colon-separated list of directories. If there is
an empty entry, such as a leading or trailing colon or two consecutive colons,
this is interpreted as the current working directory. If deviations from the
default system search path for the local interactive user are required, they
must be documented with the Information System Security Officer (ISSO).

Verify that all local interactive user initialization file executable search path statements do not contain statements that will reference a working directory other than user home directories with the following commands:

$ sudo grep -i path= /home/*/.*

/home/[localinteractiveuser]/.bash_profile:PATH=$PATH:$HOME/.local/bin:$HOME/bin
      Is it the case that any local interactive user initialization files have executable search path statements that include directories outside of their home directory and is not documented with the ISSO as an operational requirement?
      

Ensure that all interactive user initialization files executable search
path statements do not contain statements that will reference a working
directory other than the users home directory.

If user start-up files execute world-writable programs, especially in
unprotected directories, they could be maliciously modified to destroy user
files or otherwise compromise the system at the user level. If the system is
compromised at the user level, it is easier to elevate privileges to eventually
compromise the system at the root and network level.

Verify that local initialization files do not execute world-writable programs with the following command:

Note: The example will be for a system that is configured to create user home directories in the "/home" directory.

$ sudo find /home -perm -002 -type f -name ".[^.]*" -exec ls -ld {} \;
      Is it the case that any local initialization files are found to reference world-writable files?
      

Set the mode on files being executed by the user initialization files with the
following command:
$ sudo chmod o-w FILE
            
          

If a device file carries the SELinux type device_t or
unlabeled_t, then SELinux cannot properly restrict access to the
device file.

To check for incorrectly labeled device files, run following commands:
$ sudo find /dev -context *:device_t:* \( -type c -o -type b \) -printf "%p %Z\n"
$ sudo find /dev -context *:unlabeled_t:* \( -type c -o -type b \) -printf "%p %Z\n"
It should produce no output in a well-configured system.
      Is it the case that there is output?
      

Device files, which are used for communication with important system
resources, should be labeled with proper SELinux types. If any device files
carry the SELinux type device_t or unlabeled_t, report the
bug so that policy can be corrected. Supply information about what the
device is and what programs use it.

          
To check for incorrectly labeled device files, run following commands:
$ sudo find /dev -context *:device_t:* \( -type c -o -type b \) -printf "%p %Z\n"
          $ sudo find /dev -context *:unlabeled_t:* \( -type c -o -type b \) -printf "%p %Z\n"
It should produce no output in a well-configured system.

The presence of SUID and SGID executables should be tightly controlled. Users
should not be able to execute SUID or SGID binaries from user home directory partitions.

Verify the nosuid option is configured for the /home mount point,
    run the following command:
    $ sudo mount | grep '\s/home\s'
    . . . /home . . . nosuid . . .

      Is it the case that the "/home" file system does not have the "nosuid" option set?
      

The nosuid mount option can be used to prevent
execution of setuid programs in /home. The SUID and SGID permissions
should not be required in these user data directories.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/home.

The presence of SUID and SGID executables should be tightly controlled. Allowing
users to introduce SUID or SGID binaries from partitions mounted off of
removable media would allow them to introduce their own highly-privileged programs.

Verify file systems that are used for removable media are mounted with the "nosuid" option with the following command:

$ sudo more /etc/fstab

UUID=2bc871e4-e2a3-4f29-9ece-3be60c835222 /mnt/usbflash vfat noauto,owner,ro,nosuid,nodev,noexec 0 0
      Is it the case that file system found in "/etc/fstab" refers to removable media and it does not have the "nosuid" option set?
      

The nosuid mount option prevents set-user-identifier (SUID)
and set-group-identifier (SGID) permissions from taking effect. These permissions
allow users to execute binaries with the same permissions as the owner and group
of the file respectively. Users should not be allowed to introduce SUID and SGID
files into the system via partitions mounted from removeable media.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of

    any removable media partitions.

NFS mounts should not present suid binaries to users. Only vendor-supplied suid executables
should be installed to their default location on the local filesystem.

To verify the nosuid option is configured for all NFS mounts, run
the following command:
$ mount | grep nfs
All NFS mounts should show the nosuid setting in parentheses. This
is not applicable if NFS is not implemented.
      Is it the case that the setting does not show?
      

Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of
any NFS mounts.

The noexec mount option causes the system not to execute binary files. This option must be used
for mounting any file system not containing approved binary files as they may be incompatible. Executing
files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized
administrative access.

To verify the noexec option is configured for all NFS mounts, run the following command:
$ mount | grep nfs
All NFS mounts should show the noexec setting in parentheses.  This is not applicable if NFS is
not implemented.
      Is it the case that the setting does not show?
      

Add the noexec option to the fourth column of /etc/fstab for the line which controls mounting of
any NFS mounts.

The presence of SUID and SGID executables should be tightly controlled. Users
should not be able to execute SUID or SGID binaries from temporary storage partitions.

Verify the nosuid option is configured for the /dev/shm mount point,
    run the following command:
    $ sudo mount | grep '\s/dev/shm\s'
    . . . /dev/shm . . . nosuid . . .

      Is it the case that the "/dev/shm" file system does not have the "nosuid" option set?
      

The nosuid mount option can be used to prevent execution
of setuid programs in /dev/shm.  The SUID and SGID permissions should not
be required in these world-writable directories.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm.

Allowing a user account to group own a world-writable directory is
undesirable because it allows the owner of that directory to remove
or replace any files that may be placed in the directory by other
users.

The following command will discover and print world-writable directories that
are not group owned by a system account, given the assumption that only system
accounts have a gid lower than 1000.  Run it once for each local partition PART:
$ sudo find PART -xdev -type d -perm -0002 -gid +999 -print
      Is it the case that there is output?
      

All directories in local partitions which are
world-writable should be group owned by root or another
system account. If any world-writable directories are not
group owned by a system account, this should be investigated.
Following this, the files should be deleted or assigned to an
appropriate group.

Allowing a user account to own a world-writable directory is undesirable because it allows the
owner of that directory to remove or replace any files that may be placed in the directory by
other users.

The following command will discover and print world-writable directories that are not owned by
a system account, given the assumption that only system accounts have a uid lower than 500.
Run it once for each local partition PART:
$ sudo find PART -xdev -type d -perm -0002 -uid +1000 -print
      Is it the case that there is output?
      

All directories in local partitions which are world-writable should be owned by root or
another system account. If any world-writable directories are not owned by a system account,
this should be investigated. Following this, the files should be deleted or assigned to an
appropriate owner.

The umask controls the default access mode assigned to newly created files. A
umask of 077 limits new files to mode 700 or less permissive. Although umask can
be represented as a four-digit number, the first digit representing special
access modes is typically ignored or required to be 0. This requirement
applies to the globally configured system defaults and the local interactive
user defaults for each account on the system.

Verify that the default umask for all local interactive users is "077".

Identify the locations of all local interactive user home directories by looking at the "/etc/passwd" file.

Check all local interactive user initialization files for interactive users with the following command:

Note: The example is for a system that is configured to create users home directories in the "/home" directory.

# grep -ri umask /home/

/home/smithj/.bash_history:grep -i umask /etc/bashrc /etc/csh.cshrc /etc/profile
/home/smithj/.bash_history:grep -i umask /etc/login.defs
      Is it the case that any local interactive user initialization files are found to have a umask statement that sets a value less restrictive than "077"?
      

Remove the UMASK environment variable from all interactive users initialization files.

Cron logging can be used to trace the successful or unsuccessful execution
of cron jobs. It can also be used to spot intrusions into the use of the cron
facility by unauthorized and malicious users.

Verify that cron is logging to rsyslog,
run the following command:
grep -rni "cron\.\*" /etc/rsyslog.*
cron.*                                                  /var/log/cron
or
cron.* action(type="omfile" file="/var/log/cron")
      Is it the case that cron is not logging to rsyslog?
      

Cron logging must be implemented to spot intrusions or trace
cron job status. If cron is not logging to rsyslog, it
can be implemented by adding the following to the RULES section of
/etc/rsyslog.conf:
If the legacy syntax is used:
cron.*                                                  /var/log/cron
If the modern syntax (RainerScript) is used:
cron.* action(type="omfile" file="/var/log/cron")
          

If the owner of the cron.allow file is not set to root, the possibility exists for an
unauthorized user to view or edit sensitive information.

To check the ownership of /etc/cron.allow,
run the command:
$ ls -lL /etc/cron.allow
If properly configured, the output should indicate the following owner:
root
      Is it the case that /etc/cron.allow does not have an owner of root?
      

If /etc/cron.allow exists, it must be owned by root.

To properly set the owner of /etc/cron.allow, run the command:
$ sudo chown root /etc/cron.allow 
          

If the owner of the cron.allow file is not set to root, the possibility exists for an
unauthorized user to view or edit sensitive information.

To check the group ownership of /etc/cron.allow,
run the command:
$ ls -lL /etc/cron.allow
If properly configured, the output should indicate the following group-owner:
root
      Is it the case that /etc/cron.allow does not have a group owner of root?
      

If /etc/cron.allow exists, it must be group-owned by root.

To properly set the group owner of /etc/cron.allow, run the command:
$ sudo chgrp root /etc/cron.allow
          

Kernel core dumps may contain the full contents of system memory at the
time of the crash. Kernel core dumps consume a considerable amount of disk
space and may result in denial of service by exhausting the available space
on the target file system partition. Unless the system is used for kernel
development or testing, there is little need to run the kdump service.

To check that the kdump service is disabled in system boot configuration,
run the following command:
$ sudo systemctl is-enabled kdump
Output should indicate the kdump service has either not been installed,
or has been disabled at all runlevels, as shown in the example below:
$ sudo systemctl is-enabled kdump disabled

Run the following command to verify kdump is not active (i.e. not running) through current runtime configuration:
$ sudo systemctl is-active kdump

If the service is not running the command will return the following output:
inactive

The service will also be masked, to check that the kdump is masked, run the following command:
$ sudo systemctl show kdump | grep "LoadState\|UnitFileState"

If the service is masked the command will return the following outputs:

LoadState=masked

UnitFileState=masked
      Is it the case that the "kdump" is loaded and not masked?
      

The kdump service provides a kernel crash dump analyzer. It uses the kexec
system call to boot a secondary kernel ("capture" kernel) following a system
crash, which can load information from the crashed kernel for analysis.

The kdump service can be disabled with the following command:
$ sudo systemctl mask --now kdump.service
        

Ensuring that /home is mounted on its own partition enables the
setting of more restrictive mount options, and also helps ensure that
users cannot trivially fill partitions used for log or audit data storage.

Verify that a separate file system/partition has been created for /home with the following command:

$ mountpoint /home

      Is it the case that "/home is not a mountpoint" is returned?
      

If user home directories will be stored locally, create a separate partition
for /home at installation time (or migrate it later using LVM). If
/home will be mounted from another system such as an NFS server, then
creating a separate partition is not necessary at installation time, and the
mountpoint can instead be configured later.

Ensuring that /var is mounted on its own partition enables the
setting of more restrictive mount options. This helps protect
system services such as daemons or other programs which use it.
It is not uncommon for the /var directory to contain
world-writable directories installed by other software packages.

Verify that a separate file system/partition has been created for /var with the following command:

$ mountpoint /var

      Is it the case that "/var is not a mountpoint" is returned?
      

The /var directory is used by daemons and other system
services to store frequently-changing data. Ensure that /var has its own partition
or logical volume at installation time, or migrate it using LVM.

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.

Verify that a separate file system/partition has been created for /var/log/audit with the following command:

$ mountpoint /var/log/audit

      Is it the case that "/var/log/audit is not a mountpoint" is returned?
      

Audit logs are stored in the /var/log/audit directory.

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

The /tmp partition is used as temporary storage by many programs.
Placing /tmp in its own partition enables the setting of more
restrictive mount options, which can help protect programs which use it.

Verify that a separate file system/partition has been created for /tmp with the following command:

$ mountpoint /tmp

      Is it the case that "/tmp is not a mountpoint" is returned?
      

The /tmp directory is a world-writable directory used
for temporary file storage. Ensure it has its own partition or
logical volume at installation time, or migrate it using LVM.

Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to
protect data. The operating system must implement cryptographic modules adhering to the higher
standards approved by the federal government since this provides assurance they have been tested
and validated.

To verify that FIPS is enabled properly in grub, run the following command:
$ grep fips /etc/default/grub
The output should contain fips=1
      Is it the case that FIPS is not configured or enabled in grub?
      

To ensure FIPS mode is enabled, install package dracut-fips, and rebuild initramfs by running the following commands:

$ sudo yum install dracut-fips
dracut -f
After the dracut command has been run, add the argument fips=1 to the default
GRUB 2 command line for the Linux operating system in
/etc/default/grub, in the manner below:
GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=VolGroup/LogVol06 rd.lvm.lv=VolGroup/lv_swap rhgb quiet rd.shell=0 fips=1"
Finally, rebuild the grub.cfg file by using the
grub2-mkconfig -o command as follows:

                On BIOS-based machines, issue the following command as root:
~]# grub2-mkconfig -o /boot/grub2/grub.cfg
                
                On UEFI-based machines, issue the following command as root:
~]# grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
                
              
            

ACLs can provide permissions beyond those permitted through the file mode and must be
verified by the file integrity tools.

To determine that AIDE is verifying ACLs, run the following command:
$ grep acl /etc/aide.conf
Verify that the acl option is added to the correct ruleset.
      Is it the case that the acl option is missing or not added to the correct ruleset?
      

By default, the acl option is added to the FIPSR ruleset in AIDE.
If using a custom ruleset or the acl option is missing, add acl
to the appropriate ruleset.
For example, add acl to the following line in /etc/aide.conf:
FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha256
AIDE rules can be configured in multiple ways; this is merely one example that is already
configured by default.


The remediation provided with this rule adds acl to all rule sets available in
/etc/aide.conf
              

Extended attributes in file systems are used to contain arbitrary data and file metadata
with security implications.

To determine that AIDE is verifying extended file attributes, run the following command:
$ grep xattrs /etc/aide.conf
Verify that the xattrs option is added to the correct ruleset.
      Is it the case that the xattrs option is missing or not added to the correct ruleset?
      

By default, the xattrs option is added to the FIPSR ruleset in AIDE.
If using a custom ruleset or the xattrs option is missing, add xattrs
to the appropriate ruleset.
For example, add xattrs to the following line in /etc/aide.conf:
FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha256
AIDE rules can be configured in multiple ways; this is merely one example that is already
configured by default.


The remediation provided with this rule adds xattrs to all rule sets available in
/etc/aide.conf
              

File integrity tools use cryptographic hashes for verifying file contents and directories
have not been altered. These hashes must be FIPS 140-2 approved cryptographic hashes.

To determine that AIDE is configured for FIPS 140-2 file hashing, run the following command:
$ grep sha512 /etc/aide.conf
Verify that the sha512 option is added to the correct ruleset.
      Is it the case that the sha512 option is missing or not added to the correct ruleset?
      

By default, the sha512 option is added to the NORMAL ruleset in AIDE.
If using a custom ruleset or the sha512 option is missing, add sha512
to the appropriate ruleset.
For example, add sha512 to the following line in /etc/aide.conf:
NORMAL = FIPSR+sha512
AIDE rules can be configured in multiple ways; this is merely one example that is already
configured by default.

Malicious users with removable boot media can gain access to a system
configured to use removable media as the boot loader.

To verify the system is not configured to use a boot loader on removable media,
check that the grub configuration file has the set root command in each menu
entry with the following commands:
$ sudo grep -cw menuentry /boot/efi/EFI/redhat/grub.cfg
Note that the -c option for the grep command will print
only the count of menuentry occurrences. This number should match
the number of occurrences reported by the following command:
$ sudo grep "set root='hd0" /boot/efi/EFI/redhat/grub.cfg
The output should return something similar to:
set root='hd0,msdos1'
usb0, cd, fd0, etc. are some examples of removeable
media which should not exist in the lines:
set root='hd0,msdos1'
      Is it the case that it is not?
      

The system must not allow removable media to be used as the boot loader.
Remove alternate methods of booting the system from removable media.
usb0, cd, fd0, etc. are some examples of removeable
media which should not exist in the lines:
set root='hd0,msdos1'
          

It is detrimental for operating systems to provide, or install by default,
functionality exceeding requirements or mission objectives. These
unnecessary capabilities are often overlooked and therefore may remain
unsecure. They increase the risk to the platform by providing additional
attack vectors.

The telnet service provides an unencrypted remote access service which does
not provide for the confidentiality and integrity of user passwords or the
remote session. If a privileged user were to login using this service, the
privileged user password could be compromised.

Removing the telnet-server package decreases the risk of the
telnet service's accidental (or intentional) activation.

Run the following command to determine if the telnet-server package is installed:
$ rpm -q telnet-server
      Is it the case that the package is installed?
      

The telnet-server package can be removed with the following command:

$ sudo yum erase telnet-server
          

Without establishing what type of events occurred, it would be difficult
to establish, correlate, and investigate the events leading up to an outage or attack.
Ensuring the auditd service is active ensures audit records
generated by the kernel are appropriately recorded.

        
Additionally, a properly configured audit subsystem ensures that actions of
individual system users can be uniquely traced to those users so they
can be held accountable for their actions.

Run the following command to determine the current status of the
auditd service:
$ sudo systemctl is-active auditd
If the service is running, it should return the following: active
      Is it the case that the auditd service is not running?
      

The auditd service is an essential userspace component of
the Linux Auditing System, as it is responsible for writing audit records to
disk.

The auditd service can be enabled with the following command:
$ sudo systemctl enable auditd.service
      

It is critical for the appropriate personnel to be aware if a system
is at risk of failing to process audit logs as required. Without this
notification, the security personnel may be unaware of an impending failure of
the audit capability, and system operation may be adversely affected.

          
Audit processing failures include software/hardware errors, failures in the
audit capturing mechanisms, and audit storage capacity being reached or
exceeded.

To verify that the system will shutdown when auditd fails,
run the following command:
$ sudo grep "\-f " /etc/audit/audit.rules
The output should contain:
-f 
      Is it the case that the system is not configured to shutdown on auditd failures?
      

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 to the bottom of a file with suffix
.rules in the directory /etc/audit/rules.d:
-f 
          
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to the
bottom of the /etc/audit/audit.rules file:
-f 
          
        

The auditd service does not include the ability to send audit
records to a centralized server for management directly. It does, however,
include a plug-in for audit event multiplexor (audispd) to pass audit records
to a remote server.

To verify if audispd's au-remote plugin is configured, run the following command:
$ sudo grep type /etc/audisp/plugins.d/au-remote.conf
If the plugin is configured correctly, the output will show always.
      Is it the case that it is not configured?
      

Ensure the type used by audisp-remote
plug-in of the audispd audit event multiplexor is correct.
Check that the type directive in
/etc/audisp/plugins.d/au-remote.conf is always.
Restart the auditd service to apply configuration changes:
$ sudo service auditd restart
        

The audit system should have an action setup in the event the internal event queue becomes full
so that no data is lost.

Verify the audit system is configured to take an appropriate action when the internal event queue is full:
$ sudo grep -i overflow_action /etc/audisp/audispd.conf

The output should contain overflow_action = syslog

If the value of the "overflow_action" option is not set to syslog,
single, halt or the line is commented out, ask the System Administrator
to indicate how the audit logs are off-loaded to a different system or media.
      Is it the case that auditd overflow action is not set correctly?
      

The audit system should have an action setup in the event the internal event queue becomes full.
To setup an overflow action edit /etc/audisp/audispd.conf. Set overflow_action
to one of the following values: syslog, single, halt.

If option name_format is left at its default value of
none, audit events from different computers may be hard
to distinguish.

To verify that Audit Daemon is configured to record the computer node
name in the audit events, run the following command:
$ sudo grep name_format /etc/audit/auditd.conf
The output should return the following:
name_format = 
      Is it the case that name_format isn't set to ?
      

To configure Audit daemon to use a unique identifier
as computer node name in the audit events,
set name_format to 
            
          
in /etc/audit/auditd.conf.

Information stored in one location is vulnerable to accidental or incidental
deletion or alteration.Off-loading is a common process in information systems
with limited audit storage capacity.

To verify the audispd plugin off-loads audit records onto a different system or
media from the system being audited, run the following command:
$ sudo grep -i remote_server /etc/audisp/audisp-remote.conf
The output should return something similar to
remote_server = 
      Is it the case that audispd is not sending logs to a remote system?
      

Configure the audispd plugin to off-load audit records onto a different
system or media from the system being audited.

Set the remote_server option in /etc/audisp/audisp-remote.conf
with an IP address or hostname of the system that the audispd plugin should
send audit records to. For example
remote_server = 
              
            
          
        

Information stored in one location is vulnerable to accidental or incidental deletion
or alteration. Off-loading is a common process in information systems with limited
audit storage capacity.

To verify the audispd plugin encrypts audit records off-loaded onto a different
system or media from the system being audited, run the following command:

$ sudo grep -i enable_krb5 /etc/audisp/audisp-remote.conf
The output should return the following:
enable_krb5 = yes
      Is it the case that audispd is not encrypting audit records when sent over the network?
      

Configure the operating system to encrypt the transfer of off-loaded audit
records onto a different system or media from the system being audited.

Uncomment the enable_krb5 option in /etc/audisp/audisp-remote.conf,
and set it with the following line:
enable_krb5 = yes
        

Taking appropriate action in case of a filled audit storage volume will
minimize the possibility of losing audit records.

Inspect /etc/audisp/audisp-remote.conf and locate the following line to
determine if the system is configured to either send to syslog, switch to single user mode,
or halt when the disk is full:
$ sudo grep -i disk_full_action /etc/audisp/audisp-remote.conf
The output should return something similar to:
disk_full_action = single
Acceptable values also include syslog and halt.
      Is it the case that the system is not configured to switch to single user mode for corrective action?
      

Configure the action the operating system takes if the disk the audit records
are written to becomes full. Edit the file /etc/audisp/audisp-remote.conf.
Add or modify the following line, substituting ACTION appropriately:
disk_full_action = ACTION
          
Set this value to single to cause the system to switch to single user
mode for corrective action. Acceptable values also include syslog and
halt. For certain systems, the need for availability
outweighs the need to log all actions, and a different setting should be
determined.

Taking appropriate action when there is an error sending audit records to a
remote system will minimize the possibility of losing audit records.

Inspect /etc/audisp/audisp-remote.conf and locate the following line to
determine if the system is configured to perform a correct action according to the policy:
$ sudo grep -i network_failure_action /etc/audisp/audisp-remote.conf
The output should return:
network_failure_action = 
      Is it the case that the system is not configured to switch to single user mode for corrective action?
      

Configure the action the operating system takes if there is an error sending
audit records to a remote system. Edit the file /etc/audisp/audisp-remote.conf.
Add or modify the following line, substituting ACTION appropriately:
network_failure_action = ACTION
          
Set this value to single to cause the system to switch to single user
mode for corrective action. Acceptable values also include syslog and
halt. For certain systems, the need for availability
outweighs the need to log all actions, and a different setting should be
determined.
This profile configures the action to be 
            
          .

Notifying administrators of an impending disk space problem may allow them to
take corrective action prior to any disruption.

Verify Oracle Linux 7 takes action when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity with the following command:

$ sudo grep -w space_left /etc/audit/auditd.conf

space_left = %
      Is it the case that the value of the "space_left" keyword is not set to % of the storage volume allocated to audit logs, or if the line is commented out, ask the System Administrator to indicate how the system is providing real-time alerts to the SA and ISSO. If the "space_left" value is not configured to the correct value?
      

The auditd service can be configured to take an action
when disk space is running low but prior to running out of space completely.
Edit the file /etc/audit/auditd.conf. Add or modify the following line,
substituting PERCENTAGE appropriately:
space_left = PERCENTAGE%
Set this value to at least 25 to cause the system to
notify the user of an issue.

Notifying administrators of an impending disk space problem may
allow them to take corrective action prior to any disruption.

Verify Oracle Linux 7 notifies the SA and ISSO (at a minimum) when allocated audit record storage volume reaches 75 percent of the repository maximum audit record storage capacity with the following command:

$ sudo grep -w space_left_action /etc/audit/auditd.conf

space_left_action = 

If the value of the "space_left_action" is not set to "", or if the line is commented out, ask the System Administrator to indicate how the system is providing real-time alerts to the SA and ISSO.
      Is it the case that there is no evidence that real-time alerts are configured on the system?
      

The auditd service can be configured to take an action
when disk space starts to run low.
Edit the file /etc/audit/auditd.conf. Modify the following line,
substituting ACTION appropriately:
space_left_action = ACTION
          
Possible values for ACTION are described in the auditd.conf man page.
These include:

            
              syslog
            
            
              email
            
            
              exec
            
            
              suspend
            
            
              single
            
            
              halt
            
          
Set this to email (instead of the default,
which is suspend) as it is more likely to get prompt attention. Acceptable values
also include suspend, single, and halt.

Email sent to the root account is typically aliased to the
administrators of the system, who can take appropriate action.

Verify that Oracle Linux 7 is configured to notify the SA and/or ISSO (at a minimum) in the event of an audit processing failure with the following command:

$ sudo grep action_mail_acct /etc/audit/auditd.conf

action_mail_acct = 
      Is it the case that the value of the "action_mail_acct" keyword is not set to "" and/or other accounts for security personnel, the "action_mail_acct" keyword is missing, or the retuned line is commented out, ask the system administrator to indicate how they and the ISSO are notified of an audit process failure. If there is no evidence of the proper personnel being notified of an audit processing failure?
      

The auditd service can be configured to send email to
a designated account in certain situations. Add or correct the following line
in /etc/audit/auditd.conf to ensure that administrators are notified
via email for those situations:
action_mail_acct = 
          
        

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have
compromised information system accounts, is a serious and ongoing concern
and can have significant adverse impacts on organizations. Auditing the use
of privileged functions is one way to detect such misuse and identify the
risk from insider threats and the advanced persistent threat.

Verify Oracle Linux 7 audits the execution of privileged functions.

Check if Oracle Linux 7 is configured to audit the execution of the "execve" system call using the following command:

$ sudo grep execve /etc/audit/audit.rules

The output should be the following:


-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k setuid
-a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k setuid
-a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k setgid
-a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k setgid
      Is it the case that the command does not return all lines, or the lines are commented out?
      

Verify the system generates an audit record when privileged functions are executed.

If audit is using the "auditctl" tool to load the rules, run the following command:

$ sudo grep execve /etc/audit/audit.rules

If audit is using the "augenrules" tool to load the rules, run the following command:

$ sudo grep -r execve /etc/audit/rules.d
          -a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k setuid
          -a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k setuid
          -a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k setgid
          -a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k setgid


If both the "b32" and "b64" audit rules for "SUID" files are not defined, this is a finding.
If both the "b32" and "b64" audit rules for "SGID" files are not defined, this is a finding.

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.

To determine if the system is configured to audit calls to the
lchown system call, run the following command:
$ sudo grep "lchown" /etc/audit/audit.*
If the system is configured to audit this activity, it will return a line.

      Is it the case that no line is returned?
      

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!=unset -F key=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!=unset -F key=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!=unset -F key=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!=unset -F key=perm_mod
          

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.

To determine if the system is configured to audit calls to the
fchmodat system call, run the following command:
$ sudo grep "fchmodat" /etc/audit/audit.*
If the system is configured to audit this activity, it will return a line.

      Is it the case that no line is returned?
      

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!=unset -F key=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!=unset -F key=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!=unset -F key=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!=unset -F key=perm_mod
          

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.

To determine if the system is configured to audit calls to the
setxattr system call, run the following command:
$ sudo grep "setxattr" /etc/audit/audit.*
If the system is configured to audit this activity, it will return a line.

      Is it the case that no line is returned?
      

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!=unset -F key=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!=unset -F key=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!=unset -F key=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!=unset -F key=perm_mod
          

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.

Verify Oracle Linux 7 generates an audit record for unsuccessful attempts to use the truncate system call.

If the auditd daemon is configured to use the "augenrules" program to to read audit rules during daemon startup (the default), run the following command:

$ sudo grep -r truncate /etc/audit/rules.d

If the auditd daemon is configured to use the "auditctl" utility to read audit rules during daemon startup, run the following command:

$ sudo grep truncate /etc/audit/audit.rules

The output should be the following:

-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -k access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -k access
-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -k access
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -k access
      Is it the case that the command does not return a line, or the line is commented out?
      

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 truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=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 truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "semanage" command with the following command:

$ sudo auditctl -l | grep semanage

-a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect any execution attempt
of the semanage command 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 path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
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 path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "setsebool" command with the following command:

$ sudo auditctl -l | grep setsebool

-a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -k privileged
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect any execution attempt
of the setsebool command 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 path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
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 path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "chcon" command with the following command:

$ sudo auditctl -l | grep chcon

-a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -k perm_mod
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect any execution attempt
of the chcon command 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 path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
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 path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "setfiles" command with the following command:

$ sudo auditctl -l | grep setfiles

-a always,exit -F path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect any execution attempt
of the setfiles command 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 path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
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 path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion.

Verify Oracle Linux 7 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/security/opasswd" with the following command:

$ sudo auditctl -l | grep 

-w  -p wa -k logins
      Is it the case that the command does not return a line, or the line is commented out?
      

The audit system already collects login information 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 in order to watch for attempted manual
edits of files involved in storing logon events:
-w  -p wa -k logins
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 watch for unattempted manual
edits of files involved in storing logon events:
-w  -p wa -k logins
          

Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion.

Verify Oracle Linux 7 generates audit records for all account creations, modifications, disabling, and termination events that affect "/var/log/lastlog" with the following command:

$ sudo auditctl -l | grep /var/log/lastlog

-w /var/log/lastlog -p wa -k logins
      Is it the case that the command does not return a line, or the line is commented out?
      

The audit system already collects login information 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 in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins
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 watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "passwd" command with the following command:

$ sudo auditctl -l | grep passwd

-a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-passwd
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "unix_chkpwd" command with the following command:

$ sudo auditctl -l | grep unix_chkpwd

-a always,exit -F path=/usr/bin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix_chkpwd
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "gpasswd" command with the following command:

$ sudo auditctl -l | grep gpasswd

-a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -k privileged-gpasswd
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "chage" command with the following command:

$ sudo auditctl -l | grep chage

-a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -k privileged-chage
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "userhelper" command with the following command:

$ sudo auditctl -l | grep userhelper

-a always,exit -F path=/usr/bin/userhelper -F perm=x -F auid>=1000 -F auid!=unset -k privileged-userhelper
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "su" command with the following command:

$ sudo auditctl -l | grep su

-a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -k privileged-su
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "sudo" command with the following command:

$ sudo auditctl -l | grep sudo

-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -k privileged-sudo
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

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.

To verify that auditing is configured for system administrator actions, run the following command:
$ sudo auditctl -l | grep "watch=/etc/sudoers\|watch=/etc/sudoers.d\|-w /etc/sudoers\|-w /etc/sudoers.d"
      Is it the case that there is not output?
      

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

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "newgrp" command with the following command:

$ sudo auditctl -l | grep newgrp

-a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -k privileged-newgrp
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "chsh" command with the following command:

$ sudo auditctl -l | grep chsh

-a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -k privileged-chsh
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "mount" command with the following command:

$ sudo auditctl -l | grep mount

-a always,exit -F path=/usr/bin/mount -F perm=x -F auid>=1000 -F auid!=unset -k privileged-mount
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/mount -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/bin/mount -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "umount" command with the following command:

$ sudo auditctl -l | grep umount

-a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset -k privileged-umount
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "postdrop" command with the following command:

$ sudo auditctl -l | grep postdrop

-a always,exit -F path=/usr/bin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -k privileged-postdrop
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "postqueue" command with the following command:

$ sudo auditctl -l | grep postqueue

-a always,exit -F path=/usr/bin/postqueue -F perm=x -F auid>=1000 -F auid!=unset -k privileged-postqueue
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "ssh-keysign" command with the following command:

$ sudo auditctl -l | grep ssh-keysign

-a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -k privileged-ssh-keysign
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "crontab" command with the following command:

$ sudo auditctl -l | grep crontab

-a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -k privileged-crontab
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.

            
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.

Verify that Oracle Linux 7 is configured to audit the execution of the "pam_timestamp_check" command with the following command:

$ sudo auditctl -l | grep pam_timestamp_check

-a always,exit -F path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset -k privileged-pam_timestamp_check
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/sbin/pam_timestamp_check
-F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/sbin/pam_timestamp_check
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

The 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.

To determine if the system is configured to audit calls to the
create_module system call, run the following command:
$ sudo grep "create_module" /etc/audit/audit.*
If the system is configured to audit this activity, it will return a line.

      Is it the case that no line is returned?
      

To capture kernel module unloading events, use following line, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S create_module -F key=module-change

Place to add the line depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the line to a file with suffix
.rules in the directory /etc/audit/rules.d.

If the auditd daemon is configured to use the auditctl utility,
add the line to file /etc/audit/audit.rules.

The addition 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.

To determine if the system is configured to audit calls to the
init_module system call, run the following command:
$ sudo grep "init_module" /etc/audit/audit.*
If the system is configured to audit this activity, it will return a line.

      Is it the case that no line is returned?
      

To capture kernel module loading events, use following line, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

-a always,exit -F arch=ARCH -S init_module -F auid>=1000 -F auid!=unset -F key=modules


Place to add the line depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the line to a file with suffix
.rules in the directory /etc/audit/rules.d.

If the auditd daemon is configured to use the auditctl utility,
add the line to file /etc/audit/audit.rules.

The 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.

To determine if the system is configured to audit calls to the
delete_module system call, run the following command:
$ sudo grep "delete_module" /etc/audit/audit.*
If the system is configured to audit this activity, it will return a line.

      Is it the case that no line is returned?
      

To capture kernel module unloading events, use following line, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

-a always,exit -F arch=ARCH -S delete_module -F auid>=1000 -F auid!=unset -F key=modules


Place to add the line depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the line to a file with suffix
.rules in the directory /etc/audit/rules.d.

If the auditd daemon is configured to use the auditctl utility,
add the line to file /etc/audit/audit.rules.

Without generating audit records that are specific to the security and
mission needs of the organization, it would be difficult to establish,
correlate, and investigate the events relating to an incident or identify
those responsible for one.

Audit records can be generated from various components within the
information system (e.g., module or policy filter).

Verify that Oracle Linux 7 is configured to audit the execution of the "kmod" command with the following command:

$ sudo auditctl -l | grep kmod

-a always,exit -F path=/usr/bin/kmod -F perm=x -F auid>=1000 -F auid!=unset -k privileged-kmod
      Is it the case that the command does not return a line, or the line is commented out?
      

At a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/kmod -F perm=x -F auid>=1000 -F auid!=unset -F key=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:
-a always,exit -F path=/usr/bin/kmod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          

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.

Verify Oracle Linux 7 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/passwd" with the following command:

$  sudo auditctl -l | grep -E '(/etc/passwd)'

-w /etc/passwd -p wa -k identity
      Is it the case that the command does not return a line, or the line is commented out?
      

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/passwd -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/passwd -p wa -k audit_rules_usergroup_modification
        

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.

Verify Oracle Linux 7 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/group" with the following command:

$ sudo auditctl -l | grep -E '(/etc/group)'

-w /etc/group -p wa -k identity
      Is it the case that the command does not return a line, or the line is commented out?
      

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
          
          
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
        

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.

Verify Oracle Linux 7 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/gshadow" with the following command:

$ sudo auditctl -l | grep -E '(/etc/gshadow)'

-w /etc/gshadow -p wa -k identity

If the command does not return a line, or the line is commented out, this is a finding.
      Is it the case that the system is not configured to audit account changes?
      

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/gshadow -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/gshadow -p wa -k audit_rules_usergroup_modification
        

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.

Verify Oracle Linux 7 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/passwd with the following command:

$  sudo auditctl -l | grep -E '(/etc/shadow)'

-w /etc/shadow -p wa -k identity
      Is it the case that command does not return a line, or the line is commented out?
      

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/shadow -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/shadow -p wa -k audit_rules_usergroup_modification
        

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.

Verify Oracle Linux 7 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/security/opasswd" with the following command:

$ sudo auditctl -l | grep -E '(/etc/security/opasswd)'

-w /etc/security/opasswd -p wa -k identity
      Is it the case that the command does not return a line, or the line is commented out?
      

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/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/security/opasswd -p wa -k audit_rules_usergroup_modification
        

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.

To determine if the system is configured to audit calls to the
unlinkat system call, run the following command:
$ sudo grep "unlinkat" /etc/audit/audit.*
If the system is configured to audit this activity, it will return a line.

      Is it the case that no line is returned?
      

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 unlinkat -F auid>=1000 -F auid!=unset -F key=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 unlinkat -F auid>=1000 -F auid!=unset -F key=delete
          

A log server (loghost) receives syslog messages from one or more
systems. This data can be used as an additional log source in the event a
system is compromised and its local logs are suspect. Forwarding log messages
to a remote loghost also provides system administrators with a centralized
place to view the status of multiple hosts within the enterprise.

To ensure logs are sent to a remote host, examine the file
/etc/rsyslog.conf.
If using UDP, a line similar to the following should be present:
 *.* @
If using TCP, a line similar to the following should be present:
 *.* @@
If using RELP, a line similar to the following should be present:
 *.* :omrelp:
      Is it the case that no evidence that the audit logs are being off-loaded to another system or media?
      

To configure rsyslog to send logs to a remote log server,
open /etc/rsyslog.conf and read and understand the last section of the file,
which describes the multiple directives necessary to activate remote
logging.
Along with these other directives, the system can be configured
to forward its logs to a particular log server by
adding or correcting one of the following lines,
substituting 
              
                
              
             appropriately.
The choice of protocol depends on the environment of the system;
although TCP and RELP provide more reliable message delivery,
they may not be supported in all environments.

To use UDP for log message delivery:
*.* @
                
              
            
            
To use TCP for log message delivery:
*.* @@
                
              
            
            
To use RELP for log message delivery:
*.* :omrelp:
                
              
            
            
There must be a resolvable DNS CNAME or Alias record set to "" for logs to be sent correctly to the centralized logging utility.

Any process which receives messages from the network incurs some risk of receiving malicious
messages. This risk can be eliminated for rsyslog by configuring it not to listen on the
network.

Verify that the system is not accepting "rsyslog" messages from other systems unless it is
documented as a log aggregation server.
Display the contents of the rsyslog configuration files:
find /etc -maxdepth 2 -regex '/etc/rsyslog\(\.conf\|\.d\/.*\.conf\)' -exec cat '{}' \;

If any of the below lines are found, ask to see the documentation for the system being used
for log aggregation:

If using legacy syntax:
$ModLoad imtcp
$InputTCPServerRun port
$ModLoad imudp
$UDPServerRun port
$ModLoad imrelp
$InputRELPServerRun port

If using RainerScript syntax:
module(load="imtcp")
module(load="imudp")
input(type="imtcp" port="514")
input(type="imudp" port="514")

      Is it the case that rsyslog accepts remote messages and is not documented as a log aggregation system?
      

The rsyslog daemon should not accept remote messages unless the system acts as a log
server. To ensure that it is not listening on the network, ensure any of the following lines
are not found in rsyslog configuration files.

If using legacy syntax:
$ModLoad imtcp
$InputTCPServerRun port
$ModLoad imudp
$UDPServerRun port
$ModLoad imrelp
$InputRELPServerRun port
            

If using RainerScript syntax:
module(load="imtcp")
module(load="imudp")
input(type="imtcp" port="514")
input(type="imudp" port="514")

          

Virus scanning software can be used to detect if a system has been compromised by
computer viruses, as well as to limit their spread to other systems.

Verify an anti-virus solution is installed on the system. The anti-virus solution may be
bundled with an approved host-based security solution.
      Is it the case that there is no anti-virus solution installed on the system?
      

Virus scanning software can be used to protect a system from penetration from
computer viruses and to limit their spread through intermediate systems.

The virus scanning software should be configured to perform scans dynamically
on accessed files. If this capability is not available, the system must be
configured to scan, at a minimum, all altered files on the system on a daily
basis.

If the system processes inbound SMTP mail, the virus scanner must be configured
to scan all received mail.

Limiting simultaneous user logins can insulate the system from denial of service
problems caused by excessive logins. Automated login processes operating improperly or
maliciously may result in an exceptional number of simultaneous login sessions.

Verify Oracle Linux 7 limits the number of concurrent sessions to
"" for all
accounts and/or account types with the following command:
$ grep -r -s maxlogins /etc/security/limits.conf /etc/security/limits.d/*.conf
/etc/security/limits.conf:* hard maxlogins 10
This can be set as a global domain (with the * wildcard) but may be set differently for multiple domains.
      Is it the case that the "maxlogins" item is missing, commented out, or the value is set greater
than "" and
is not documented with the Information System Security Officer (ISSO) as an
operational requirement for all domains that have the "maxlogins" item
assigned'?
      

Limiting the number of allowed users and sessions per user can limit risks related to Denial of
Service attacks. This addresses concurrent sessions for a single account and does not address
concurrent sessions by a single user via multiple accounts. To set the number of concurrent
sessions per user add the following line in /etc/security/limits.conf or
a file under /etc/security/limits.d/:
* hard maxlogins 
            
          

In order to prevent unauthorized connection of devices, unauthorized transfer of information,
or unauthorized tunneling (i.e., embedding of data types within data types), organizations must
disable or restrict unused or unnecessary physical and logical ports/protocols on information
systems.

              
Operating systems are capable of providing a wide variety of functions and services.
Some of the functions and services provided by default may not be necessary to support
essential organizational operations.
Additionally, it is sometimes convenient to provide multiple services from a single component
(e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by
one component.

              
To support the requirements and principles of least functionality, the operating system must
support the organizational requirements, providing only essential capabilities and limiting the
use of ports, protocols, and/or services to only those required, authorized, and approved to
conduct official business.

Inspect the list of enabled firewall ports and verify they are configured correctly by running
the following command:

$ sudo firewall-cmd --list-all

Ask the System Administrator for the site or program Ports, Protocols, and Services Management Component Local Service Assessment (PPSM CLSA). Verify the services allowed by the firewall match the PPSM CLSA.
      Is it the case that there are additional ports, protocols, or services that are not in the PPSM CLSA, or there are ports, protocols, or services that are prohibited by the PPSM Category Assurance List (CAL), or there are no firewall rules configured?
      

Configure the firewalld ports to allow approved services to have access to the system.
To configure firewalld to open ports, run the following command:
firewall-cmd --permanent --add-port=port_number/tcp
              
To configure firewalld to allow access for pre-defined services, run the following
command:
firewall-cmd --permanent --add-service=service_name
              
            

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore
cannot be relied upon to provide confidentiality or integrity, and system data may be compromised.

Operating systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to
cryptographic modules.

FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules
utilize authentication that meets industry and government requirements. For government systems, this allows
Security Levels 1, 2, 3, or 4 for use on Oracle Linux 7.

Only FIPS ciphers should be used. To verify that only FIPS-approved
ciphers are in use, run the following command:
$ sudo grep Ciphers /etc/ssh/sshd_config
The output should contain only following ciphers (or a subset) in the exact order:
aes256-ctr,aes192-ctr,aes128-ctr
      Is it the case that FIPS ciphers are not configured or the enabled ciphers are not FIPS-approved?
      

Limit the ciphers to those algorithms which are FIPS-approved.
The following line in /etc/ssh/sshd_config
demonstrates use of FIPS-approved ciphers:
Ciphers aes256-ctr,aes192-ctr,aes128-ctr
This rule ensures that there are configured ciphers mentioned
above (or their subset), keeping the given order of algorithms.

Terminating an idle session within a short time period reduces
the window of opportunity for unauthorized personnel to take control of a
management session enabled on the console or console port that has been
left unattended.

Run the following command to ensure the TMOUT value is configured for all users
on the system:

$ sudo grep TMOUT /etc/profile /etc/profile.d/*.sh

The output should return the following:
TMOUT=
      Is it the case that value of TMOUT is not less than or equal to expected setting?
      

Setting the TMOUT option in /etc/profile ensures that
all user sessions will terminate based on inactivity.
The value of TMOUT should be exported and read only.
The TMOUT

setting in a file loaded by /etc/profileor /etc/bashrc, e.g.
/etc/profile.d/tmout.sh should read as follows:
typeset -xr TMOUT=
            
or
declare -xr TMOUT=
            
Using the typeset keyword is preferred for wider compatibility with ksh and other shells.

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.

To determine how the SSH daemon's Banner option is set, run the following command:

$ sudo grep -i Banner /etc/ssh/sshd_config

If a line indicating /etc/issue is returned, then the required value is set.

      Is it the case that the required value is not set?
      

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.

Without cryptographic integrity protections, information can be
altered by unauthorized users without detection. The ssl directive specifies
whether to use TLS or not. If not specified it will default to no.
It should be set to start_tls rather than doing LDAP over SSL.

If the system is not using TLS, set the ldap_id_use_start_tls option
in /etc/sssd/sssd.conf to true.
      Is it the case that the 'ldap_id_use_start_tls' option is not set to 'true'?
      

The LDAP client should be configured to implement TLS for the integrity
of all remote LDAP authentication sessions. If the id_provider is
set to ldap or ipa in /etc/sssd/sssd.conf or any of the
/etc/sssd/sssd.conf.d configuration files, ldap_id_use_start_tls
must be set to true.

            
To check if LDAP is configured to use TLS when id_provider is
set to ldap or ipa, use the following command:
$ sudo grep -i ldap_id_use_start_tls /etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf
          

Without a valid certificate presented to the LDAP client backend, the identity of a
server can be forged compromising LDAP remote access sessions.

To verify the LDAP client backend demands a valid certificate from the server in
remote LDAP access sessions, run the following command:
$ sudo grep ldap_tls_reqcert /etc/sssd/sssd.conf
The output should return the following:
ldap_tls_reqcert = demand
      Is it the case that the TLS reqcert is not set to demand?
      

Configure SSSD to demand a valid certificate from the server to
protect the integrity of LDAP remote access sessions by setting
the ldap_tls_reqcert option in /etc/sssd/sssd.conf
to demand.

Without cryptographic integrity protections, information can be altered by
unauthorized users without detection.

            
Cryptographic mechanisms used for
protecting the integrity of information include, for example, signed hash
functions using asymmetric cryptography enabling distribution of the public key
to verify the hash information while maintaining the confidentiality of the key
used to generate the hash.

To verify the operating system implements cryptography to protect the integrity of
remote ldap access sessions, run the following command:
$ sudo grep ldap_tls_cacertdir /etc/sssd/sssd.conf
The output should return the following with a correctly configured CA cert path:
ldap_tls_cacertdir /path/to/tls/cacert
      Is it the case that the TLS CA cert is not configured?
      

Configure SSSD to implement cryptography to protect the
integrity of LDAP remote access sessions. By setting
the ldap_tls_cacertdir option in /etc/sssd/sssd.conf
to point to the path for the X.509 certificates used for peer authentication.
ldap_tls_cacertdir /path/to/tls/cacert
          

Address space layout randomization (ASLR) makes it more difficult for an
attacker to predict the location of attack code they have introduced into a
process's address space during an attempt at exploitation. Additionally,
ASLR makes it more difficult for an attacker to know the location of
existing code in order to re-purpose it using return oriented programming
(ROP) techniques.

The runtime status of the kernel.randomize_va_space kernel parameter can be queried
by running the following command:
$ sysctl kernel.randomize_va_space
2.

      Is it the case that the correct value is not returned?
      

To set the runtime status of the kernel.randomize_va_space kernel parameter, run the following command: $ sudo sysctl -w kernel.randomize_va_space=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: kernel.randomize_va_space = 2
            

Without protection of the transmitted information, confidentiality, and
integrity may be compromised because unprotected communications can be
intercepted and either read or altered.

Run the following command to determine if the openssh-server package is installed: $ rpm -q openssh-server
      Is it the case that the package is not installed?
      

The openssh-server package should be installed.
The openssh-server package can be installed with the following command:

$ sudo yum install openssh-server
        

Without protection of the transmitted information, confidentiality, and
integrity may be compromised because unprotected communications can be
intercepted and either read or altered.

          
This checklist item applies to both internal and external networks and all types
of information system components from which information can be transmitted (e.g., servers,
mobile devices, notebook computers, printers, copiers, scanners, etc). Communication paths
outside the physical protection of a controlled boundary are exposed to the possibility
of interception and modification.

Run the following command to determine the current status of the
sshd service:
$ sudo systemctl is-active sshd
If the service is running, it should return the following: active
      Is it the case that sshd service is disabled?
      

The SSH server service, sshd, is commonly needed.

The sshd service can be enabled with the following command:
$ sudo systemctl enable sshd.service
        

Terminating an idle ssh session within a short time period reduces the window of
opportunity for unauthorized personnel to take control of a management session
enabled on the console or console port that has been let unattended.

Run the following command to see what the timeout interval is:
$ sudo grep ClientAliveInterval /etc/ssh/sshd_config
If properly configured, the output should be:
ClientAliveInterval 
      Is it the case that it is commented out or not configured properly?
      

SSH allows administrators to set a network responsiveness timeout interval.
After this interval has passed, the unresponsive client will be automatically logged out.

            
To set this timeout interval, edit the following line in /etc/ssh/sshd_config as
follows:
ClientAliveInterval 
                
              
            
            
            
The timeout interval is given in seconds. For example, have a timeout
of 10 minutes, set interval to 600.

            
If a shorter timeout has already been set for the login shell, that value will
preempt any SSH setting made in /etc/ssh/sshd_config. Keep in mind that
some processes may stop SSH from correctly detecting that the user is idle.

Configuring this setting for the SSH daemon provides additional
assurance that remote login via SSH will require a password, even
in the event of misconfiguration elsewhere.

To check which SSH protocol version is allowed, check version of
openssh-server with following command:
$ rpm -qi openssh-server | grep Version
Versions equal to or higher than 7.4 have deprecated the RhostsRSAAuthentication option.
If version is lower than 7.4, run the following command to check configuration:
To determine how the SSH daemon's RhostsRSAAuthentication option is set, run the following command:

$ sudo grep -i RhostsRSAAuthentication /etc/ssh/sshd_config

If a line indicating no is returned, then the required value is set.

      Is it the case that the required value is not set?
      

SSH can allow authentication through the obsolete rsh
command through the use of the authenticating user's SSH keys. This should be disabled.

            
To ensure this behavior is disabled, add or correct the
following line in /etc/ssh/sshd_config:
RhostsRSAAuthentication no
          

This ensures a user login will be terminated as soon as the ClientAliveInterval
is reached.

To ensure ClientAliveInterval is set correctly, run the following command:

$ sudo grep ClientAliveCountMax /etc/ssh/sshd_config

If properly configured, the output should be:
ClientAliveCountMax 0

In this case, the SSH timeout occurs precisely when
the ClientAliveInterval is set.
      Is it the case that it is commented out or not configured properly?
      

The SSH server sends at most ClientAliveCountMax messages
during a SSH session and waits for a response from the SSH client.
The option ClientAliveInterval configures timeout after
each ClientAliveCountMax message. If the SSH server does not
receive a response from the client, then the connection is considered unresponsive
and terminated.

To ensure the SSH timeout occurs precisely when the
ClientAliveInterval is set, set the ClientAliveCountMax to
value of 0 in


/etc/ssh/sshd_config:

SSH trust relationships mean a compromise on one host
can allow an attacker to move trivially to other hosts.

To determine how the SSH daemon's IgnoreRhosts option is set, run the following command:

$ sudo grep -i IgnoreRhosts /etc/ssh/sshd_config

If a line indicating yes is returned, then the required value is set.

      Is it the case that the required value is not set?
      

SSH can emulate the behavior of the obsolete rsh
command in allowing users to enable insecure access to their
accounts via .rhosts files.

The default SSH configuration disables support for .rhosts. The appropriate
configuration is used if no value is set for IgnoreRhosts.

To explicitly disable support for .rhosts files, add or correct the following line in


/etc/ssh/sshd_config:

IgnoreRhosts yes
          

Providing users feedback on when account accesses last occurred facilitates user
recognition and reporting of unauthorized account use.

To determine how the SSH daemon's PrintLastLog option is set, run the following command:

$ sudo grep -i PrintLastLog /etc/ssh/sshd_config

If a line indicating yes is returned, then the required value is set.

      Is it the case that the required value is not set?
      

Ensure that SSH will display the date and time of the last successful account logon.

The default SSH configuration enables print of the date and time of the last login.
The appropriate configuration is used if no value is set for PrintLastLog.

To explicitly enable LastLog in SSH, add or correct the following line in


/etc/ssh/sshd_config:

PrintLastLog yes
          

Even though the communications channel may be encrypted, an additional layer of
security is gained by extending the policy of not logging directly on as root.
In addition, logging in with a user-specific account provides individual
accountability of actions performed on the system and also helps to minimize
direct attack attempts on root's password.

To determine how the SSH daemon's PermitRootLogin option is set, run the following command:

$ sudo grep -i PermitRootLogin /etc/ssh/sshd_config

If a line indicating no is returned, then the required value is set.

      Is it the case that the required value is not set?
      

The root user should never be allowed to login to a
system directly over a network.
To disable root login via SSH, add or correct the following line in


/etc/ssh/sshd_config:

PermitRootLogin no
          

Configuring this setting for the SSH daemon provides additional
assurance that remote login via SSH will require a password, even
in the event of misconfiguration elsewhere.

To determine how the SSH daemon's IgnoreUserKnownHosts option is set, run the following command:

$ sudo grep -i IgnoreUserKnownHosts /etc/ssh/sshd_config

If a line indicating yes is returned, then the required value is set.

      Is it the case that the required value is not set?
      

SSH can allow system users to connect to systems if a cache of the remote
systems public keys is available.  This should be disabled.

            
To ensure this behavior is disabled, add or correct the following line in


/etc/ssh/sshd_config:

IgnoreUserKnownHosts yes
          

SSH protocol version 1 is an insecure implementation of the SSH protocol and
has many well-known vulnerability exploits. Exploits of the SSH daemon could provide
immediate root access to the system.

To check which SSH protocol version is allowed, check version of openssh-server with following command:

$ rpm -qi openssh-server | grep Version

Versions equal to or higher than 7.4 only allow Protocol 2.
If version is lower than 7.4, run the following command to check configuration:
$ sudo grep Protocol /etc/ssh/sshd_config
If configured properly, output should be Protocol 2
      Is it the case that it is commented out or is not set correctly to Protocol 2?
      

Only SSH protocol version 2 connections should be
permitted. The default setting in
/etc/ssh/sshd_config is correct, and can be
verified by ensuring that the following
line appears:
Protocol 2
          

DoD Information Systems are required to use FIPS-approved cryptographic hash
functions. The only SSHv2 hash algorithms meeting this requirement is SHA2.

Only FIPS-approved MACs should be used. To verify that only FIPS-approved
MACs are in use, run the following command:
$ sudo grep -i macs /etc/ssh/sshd_config
The output should contain only following MACs (or a subset) in the exact order:
MACs 
      Is it the case that MACs option is commented out or not using FIPS-approved hash algorithms?
      

Limit the MACs to those hash algorithms which are FIPS-approved.
The following line in /etc/ssh/sshd_config
demonstrates use of FIPS-approved MACs:
MACs hmac-sha2-512,hmac-sha2-256
This rule ensures that there are configured MACs mentioned
above (or their subset), keeping the given order of algorithms.

If a public host key file is modified by an unauthorized user, the SSH service
may be compromised.

To check the permissions of /etc/ssh/*.pub,
run the command:
$ ls -l /etc/ssh/*.pub
If properly configured, the output should indicate the following permissions:
-rw-r--r--
      Is it the case that /etc/ssh/*.pub does not have unix mode -rw-r--r--?
      

 To properly set the permissions of /etc/ssh/*.pub, run the command: $ sudo chmod 0644 /etc/ssh/*.pub
        

If an unauthorized user obtains the private SSH host key file, the host could be
impersonated.

To check the permissions of /etc/ssh/*_key,
run the command:
$ ls -l /etc/ssh/*_key
If properly configured, the output should indicate the following permissions:
-rw-------
      Is it the case that /etc/ssh/*_key does not have unix mode -rw-------?
      

SSH server private keys - files that match the /etc/ssh/*_key glob, have to have restricted permissions.
If those files are owned by the root user and the root group, they have to have the 0600 permission or stricter.
If they are owned by the root user, but by a dedicated group ssh_keys, they can have the 0640 permission or stricter.

GSSAPI authentication is used to provide additional authentication mechanisms to
applications. Allowing GSSAPI authentication through SSH exposes the system's
GSSAPI to remote hosts, increasing the attack surface of the system.

To determine how the SSH daemon's GSSAPIAuthentication option is set, run the following command:

$ sudo grep -i GSSAPIAuthentication /etc/ssh/sshd_config

If a line indicating no is returned, then the required value is set.

      Is it the case that the required value is not set?
      

Unless needed, SSH should not permit extraneous or unnecessary
authentication mechanisms like GSSAPI.

The default SSH configuration disallows authentications based on GSSAPI. The appropriate
configuration is used if no value is set for GSSAPIAuthentication.

To explicitly disable GSSAPI authentication, add or correct the following line in


/etc/ssh/sshd_config:

GSSAPIAuthentication no
          

Kerberos authentication for SSH is often implemented using GSSAPI. If Kerberos
is enabled through SSH, the SSH daemon provides a means of access to the
system's Kerberos implementation.
Configuring these settings for the SSH daemon provides additional assurance that remote logon via SSH will not use unused methods of authentication, even in the event of misconfiguration elsewhere.

To determine how the SSH daemon's KerberosAuthentication option is set, run the following command:

$ sudo grep -i KerberosAuthentication /etc/ssh/sshd_config

If a line indicating no is returned, then the required value is set.

      Is it the case that the required value is not set?
      

Unless needed, SSH should not permit extraneous or unnecessary
authentication mechanisms like Kerberos.

The default SSH configuration disallows authentication validation through Kerberos.
The appropriate configuration is used if no value is set for KerberosAuthentication.

To explicitly disable Kerberos authentication, add or correct the following line in


/etc/ssh/sshd_config:

KerberosAuthentication no
          

If other users have access to modify user-specific SSH configuration files, they
may be able to log into the system as another user.

To determine how the SSH daemon's StrictModes option is set, run the following command:

$ sudo grep -i StrictModes /etc/ssh/sshd_config

If a line indicating yes is returned, then the required value is set.

      Is it the case that the required value is not set?
      

SSHs StrictModes option checks file and ownership permissions in
the user's home directory .ssh folder before accepting login. If world-
writable permissions are found, logon is rejected.

The default SSH configuration has StrictModes enabled. The appropriate
configuration is used if no value is set for StrictModes.

To explicitly enable StrictModes in SSH, add or correct the following line in


/etc/ssh/sshd_config:

StrictModes yes
          

SSH daemon privilege separation causes the SSH process to drop root privileges
when not needed which would decrease the impact of software vulnerabilities in
the unprivileged section.

To check if UsePrivilegeSeparation is enabled or set correctly, run the
following command:
$ sudo grep UsePrivilegeSeparation /etc/ssh/sshd_config
If configured properly, output should be .
      Is it the case that it is commented out or is not enabled?
      

When enabled, SSH will create an unprivileged child process that
has the privilege of the authenticated user. To enable privilege separation in
SSH, add or correct the following line in the /etc/ssh/sshd_config file:
UsePrivilegeSeparation 
            
          

If compression is allowed in an SSH connection prior to authentication,
vulnerabilities in the compression software could result in compromise of the
system from an unauthenticated connection, potentially with root privileges.

To check if compression is enabled or set correctly, run the
following command:
$ sudo grep Compression /etc/ssh/sshd_config
If configured properly, output should be no or delayed.
      Is it the case that it is commented out, or is not set to no or delayed?
      

Compression is useful for slow network connections over long
distances but can cause performance issues on local LANs. If use of compression
is required, it should be enabled only after a user has authenticated; otherwise,
it should be disabled. To disable compression or delay compression until after
a user has successfully authenticated, add or correct the following line in the
/etc/ssh/sshd_config file:
Compression 
            
          

Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate.
Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network.
Organizations should consider endpoints that may not have regular access to the authoritative time server (e.g., mobile, teleworking, and tactical endpoints).

Verify Oracle Linux 7 is securely comparing internal information system clocks at a regular interval with an NTP server with the following command:
$ sudo grep maxpoll /etc/ntp.conf /etc/chrony.conf /etc/chrony.d/
server [ntp.server.name] iburst maxpoll .
      Is it the case that "maxpoll" has not been set to the value of "", is commented out, or is missing?
      

The maxpoll should be configured to
 in /etc/ntp.conf or
/etc/chrony.conf (or /etc/chrony.d/) to continuously poll time servers. To configure
maxpoll in /etc/ntp.conf or /etc/chrony.conf (or /etc/chrony.d/)
add the following after each server, pool or peer entry:
maxpoll 
          
to server directives. If using chrony, any pool directives
should be configured too.

Denial of Service (DoS) is a condition when a resource is not available for legitimate users. When
this occurs, the organization either cannot accomplish its mission or must
operate at degraded capacity.

              
This can help mitigate simple “ack loop” DoS attacks, wherein a buggy or
malicious middlebox or man-in-the-middle can rewrite TCP header fields in
manner that causes each endpoint to think that the other is sending invalid
TCP segments, thus causing each side to send an unterminating stream of
duplicate acknowledgments for invalid segments.

To verify that the operating system protects against or limits the effects of DoS
attacks by ensuring implementation of rate-limiting measures
on impacted network interfaces, run the following command:
# grep 'net.ipv4.tcp_invalid_ratelimit' /etc/sysctl.conf /etc/sysctl.d/*
The command should output the following line:
/etc/sysctl.conf:net.ipv4.tcp_invalid_ratelimit = 
The file where the line has been found can differ, but it must be either /etc/sysctl.conf
or a file located under the /etc/sysctl.d/ directory.
      Is it the case that rate limiting of duplicate TCP acknowledgments is not configured?
      

Make sure that the system is configured to limit the maximal rate for sending
duplicate acknowledgments in response to incoming TCP packets that are for
an existing connection but that are invalid due to any of these reasons:

(a) out-of-window sequence number, (b) out-of-window acknowledgment number,
or (c) PAWS (Protection Against Wrapped Sequence numbers) check failure
This measure protects against or limits effects of DoS attacks against the system.
Set the system to implement rate-limiting measures by adding the following line to
/etc/sysctl.conf or a configuration file in the /etc/sysctl.d/ directory
(or modify the line to have the required value):
net.ipv4.tcp_invalid_ratelimit = 
              
Issue the following command to make the changes take effect:
# sysctl --system
            

Access control methods provide the ability to enhance system security posture
by restricting services and known good IP addresses and address ranges. This
prevents connections from unknown hosts and protocols.

Run the following command to determine the current status of the
firewalld service:
$ sudo systemctl is-active firewalld
If the service is running, it should return the following: active
      Is it the case that the "firewalld" service is disabled, masked, or not started.?
      

The firewalld service can be enabled with the following command:
$ sudo systemctl enable firewalld.service
            

Users need to be aware of activity that occurs regarding their account. Providing users with
information regarding the number of unsuccessful attempts that were made to login to their
account allows the user to determine if any unauthorized activity has occurred and gives them
an opportunity to notify administrators.

Verify users are provided with feedback on when account accesses last occurred with the following command:

$ sudo grep pam_lastlog /etc/pam.d/postlogin

session required pam_lastlog.so showfailed
      Is it the case that "pam_lastlog.so" is not properly configured in "/etc/pam.d/postlogin" file?
      

To configure the system to notify users of last logon/access using pam_lastlog,
add or correct the pam_lastlog settings in /etc/pam.d/postlogin
to include showfailed option, such as:
session     required    pam_lastlog.so showfailed
And make sure that the silent option is not set for this specific line.

The .shosts files are used to configure host-based authentication for
individual users or the system via SSH. Host-based authentication is not
sufficient for preventing unauthorized access to the system, as it does not
require interactive identification and authentication of a connection request,
or for the use of two-factor authentication.

To verify that there are no .shosts files
on the system, run the following command:
$ sudo find / -name '.shosts'
      Is it the case that .shosts files exist?
      

The ~/.shosts (in each user's home directory) files
list remote hosts and users that are trusted by the
local system. To remove these files, run the following command
to delete them from any location:
$ sudo find / -name '.shosts' -type f -delete
          

The shosts.equiv files are used to configure host-based authentication for the system via SSH.
Host-based authentication is not sufficient for preventing unauthorized access to the system,
as it does not require interactive identification and authentication of a connection request,
or for the use of two-factor authentication.

Verify that there are no shosts.equiv files on the system, run the following command:
$ find / -name shosts.equiv
      Is it the case that shosts.equiv files exist?
      

The shosts.equiv file lists remote hosts and users that are trusted by the local
system. To remove these files, run the following command to delete them from any location:
$ sudo rm /[path]/[to]/[file]/shosts.equiv
          

To provide availability for name resolution services, multiple redundant
name servers are mandated. A failure in name resolution could lead to the
failure of security functions requiring name resolution, which may include
time synchronization, centralized authentication, and remote system logging.

Verify that DNS servers have been configured properly, perform the following:
$ sudo grep nameserver /etc/resolv.conf
      Is it the case that less than two lines are returned that are not commented out?
      

Determine whether the system is using local or DNS name resolution with the
following command:
$ sudo grep hosts /etc/nsswitch.conf
hosts: files dns
If the DNS entry is missing from the host's line in the "/etc/nsswitch.conf"
file, the "/etc/resolv.conf" file must be empty.
Verify the "/etc/resolv.conf" file is empty with the following command:
$ sudo ls -al /etc/resolv.conf
-rw-r--r-- 1 root root 0 Aug 19 08:31 resolv.conf
If the DNS entry is found on the host's line of the "/etc/nsswitch.conf" file,
then verify the following:

Multiple Domain Name System (DNS) Servers should be configured
in /etc/resolv.conf. This provides redundant name resolution services
in the event that a domain server crashes. To configure the system to contain
as least 2 DNS servers, add a corresponding nameserver
ip_address
           entry in /etc/resolv.conf for each DNS
server where ip_address is the IP address of a valid DNS server.
For example:
search example.com
nameserver 192.168.0.1
nameserver 192.168.0.2
        

Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router,
which can be used to bypass network security measures. This requirement
applies only to the forwarding of source-routerd traffic, such as when IPv4
forwarding is enabled and the system is functioning as a router.

              
Accepting source-routed packets in the IPv4 protocol has few legitimate
uses. It should be disabled unless it is absolutely required.

The runtime status of the net.ipv4.conf.all.accept_source_route kernel parameter can be queried
by running the following command:
$ sysctl net.ipv4.conf.all.accept_source_route
0.

      Is it the case that the correct value is not returned?
      

To set the runtime status of the net.ipv4.conf.all.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.all.accept_source_route = 0
            

Enabling reverse path filtering drops packets with source addresses
that should not have been able to be received on the interface they were
received on. It should not be used on systems which are routers for
complicated networks, but is helpful for end hosts and routers serving small
networks.

The runtime status of the net.ipv4.conf.all.rp_filter parameter can be queried
by running the following command:
$ sysctl net.ipv4.conf.all.rp_filter
The output of the command should indicate either:
net.ipv4.conf.all.rp_filter = 1
or:
net.ipv4.conf.all.rp_filter = 2
The output of the command should not indicate:
net.ipv4.conf.all.rp_filter = 0

The preferable way how to assure the runtime compliance is to have
correct persistent configuration, and rebooting the system.

The persistent sysctl parameter configuration is performed by specifying the appropriate
assignment in any file located in the /etc/sysctl.d directory.
Verify that there is not any existing incorrect configuration by executing the following command:
$ grep -r '^\s*net.ipv4.conf.all.rp_filter\s*=' /etc/sysctl.conf /etc/sysctl.d
The command should not find any assignments other than:
net.ipv4.conf.all.rp_filter = 1
or:
net.ipv4.conf.all.rp_filter = 2

Conflicting assignments are not allowed.
      Is it the case that the net.ipv4.conf.all.rp_filter is not set to 1 or 2 or is configured to be 0?
      

To set the runtime status of the net.ipv4.conf.all.rp_filter kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.rp_filter=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.all.rp_filter = 1
            

Enabling reverse path filtering drops packets with source addresses
that should not have been able to be received on the interface they were
received on. It should not be used on systems which are routers for
complicated networks, but is helpful for end hosts and routers serving small
networks.

The runtime status of the net.ipv4.conf.default.rp_filter kernel parameter can be queried
by running the following command:
$ sysctl net.ipv4.conf.default.rp_filter
1.

      Is it the case that the correct value is not returned?
      

To set the runtime status of the net.ipv4.conf.default.rp_filter kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.rp_filter=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.default.rp_filter = 1
            

Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router,
which can be used to bypass network security measures.

Accepting source-routed packets in the IPv4 protocol has few legitimate
uses. It should be disabled unless it is absolutely required, such as when
IPv4 forwarding is enabled and the system is legitimately functioning as a
router.

The runtime status of the net.ipv4.conf.default.accept_source_route kernel parameter can be queried
by running the following command:
$ sysctl net.ipv4.conf.default.accept_source_route
0.

      Is it the case that the correct value is not returned?
      

To set the runtime status of the net.ipv4.conf.default.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.default.accept_source_route = 0
            

Responding to broadcast (ICMP) echoes facilitates network mapping
and provides a vector for amplification attacks.

Ignoring ICMP echo requests (pings) sent to broadcast or multicast
addresses makes the system slightly more difficult to enumerate on the network.

The runtime status of the net.ipv4.icmp_echo_ignore_broadcasts kernel parameter can be queried
by running the following command:
$ sysctl net.ipv4.icmp_echo_ignore_broadcasts
1.

      Is it the case that the correct value is not returned?
      

To set the runtime status of the net.ipv4.icmp_echo_ignore_broadcasts kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.icmp_echo_ignore_broadcasts = 1
            

ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages modify the
host's route table and are unauthenticated. An illicit ICMP redirect
message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should
be disabled unless absolutely required.

The runtime status of the net.ipv4.conf.default.accept_redirects kernel parameter can be queried
by running the following command:
$ sysctl net.ipv4.conf.default.accept_redirects
0.

      Is it the case that the correct value is not returned?
      

To set the runtime status of the net.ipv4.conf.default.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.default.accept_redirects = 0
            

ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages modify the
host's route table and are unauthenticated. An illicit ICMP redirect
message could result in a man-in-the-middle attack.

This feature of the IPv4 protocol has few legitimate uses. It should be
disabled unless absolutely required."

The runtime status of the net.ipv4.conf.all.accept_redirects kernel parameter can be queried
by running the following command:
$ sysctl net.ipv4.conf.all.accept_redirects
0.

      Is it the case that the correct value is not returned?
      

To set the runtime status of the net.ipv4.conf.all.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.all.accept_redirects = 0
            

ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages contain information
from the system's route table possibly revealing portions of the network topology.

The ability to send ICMP redirects is only appropriate for systems acting as routers.

The runtime status of the net.ipv4.conf.default.send_redirects kernel parameter can be queried
by running the following command:
$ sysctl net.ipv4.conf.default.send_redirects
0.

      Is it the case that the correct value is not returned?
      

To set the runtime status of the net.ipv4.conf.default.send_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.default.send_redirects = 0
            

ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages contain information
from the system's route table possibly revealing portions of the network topology.

The ability to send ICMP redirects is only appropriate for systems acting as routers.

The runtime status of the net.ipv4.conf.all.send_redirects kernel parameter can be queried
by running the following command:
$ sysctl net.ipv4.conf.all.send_redirects
0.

      Is it the case that the correct value is not returned?
      

To set the runtime status of the net.ipv4.conf.all.send_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.all.send_redirects = 0
            

Network interfaces in promiscuous mode allow for the capture of all network traffic
visible to the system. If unauthorized individuals can access these applications, it
may allow them to collect information such as logon IDs, passwords, and key exchanges
between systems.

          
If the system is being used to perform a network troubleshooting function, the use of these
tools must be documented with the Information Systems Security Manager (ISSM) and restricted
to only authorized personnel.

Verify that Promiscuous mode of an interface is disabled, run the following command:
$ ip link | grep PROMISC
      Is it the case that any network device is in promiscuous mode?
      

The system should not be acting as a network sniffer, which can
capture all traffic on the network to which it is connected. Run the following
to determine if any interface is running in promiscuous mode:
$ ip link | grep PROMISC
Promiscuous mode of an interface can be disabled with the following command:
$ sudo ip link set dev device_name multicast off promisc off
        

If unrestricted mail relaying is permitted, unauthorized senders could use this
host as a mail relay for the purpose of sending spam or other unauthorized
activity.

Verify that Oracle Linux 7 is configured to prevent unrestricted mail relaying,
run the following command:
$ sudo postconf -n smtpd_client_restrictions
      Is it the case that the "smtpd_client_restrictions" parameter contains any entries other than "permit_mynetworks" and "reject"?
      

Modify the /etc/postfix/main.cf file to restrict client connections
to the local network with the following command:
$ sudo postconf -e 'smtpd_client_restrictions = permit_mynetworks,reject'
              

Removing the vsftpd package decreases the risk of its
accidental activation.

Run the following command to determine if the vsftpd package is installed:
$ rpm -q vsftpd
      Is it the case that the package is installed?
      

The vsftpd package can be removed with the following command:  $ sudo yum erase vsftpd
          

Removing the tftp-server package decreases the risk of the accidental
(or intentional) activation of tftp services.

            
If TFTP is required for operational support (such as transmission of router
configurations), its use must be documented with the Information Systems
Securty Manager (ISSM), restricted to only authorized personnel, and have
access control rules established.

Run the following command to determine if the tftp-server package is installed:
$ rpm -q tftp-server
      Is it the case that the package is installed?
      

The tftp-server package can be removed with the following command:  $ sudo yum erase tftp-server
          

Disable X11 forwarding unless there is an operational requirement to use X11
applications directly. There is a small risk that the remote X11 servers of
users who are logged in via SSH with X11 forwarding could be compromised by
other users on the X11 server. Note that even if X11 forwarding is disabled,
users can always install their own forwarders.

To determine how the SSH daemon's X11Forwarding option is set, run the following command:

$ sudo grep -i X11Forwarding /etc/ssh/sshd_config

If a line indicating no is returned, then the required value is set.

      Is it the case that the required value is not set?
      

The X11Forwarding parameter provides the ability to tunnel X11 traffic
through the connection to enable remote graphic connections.
SSH has the capability to encrypt remote X11 connections when SSH's
X11Forwarding option is enabled.

The default SSH configuration disables X11Forwarding. The appropriate
configuration is used if no value is set for X11Forwarding.

To explicitly disable X11 Forwarding, add or correct the following line in


/etc/ssh/sshd_config:

X11Forwarding no
          

When X11 forwarding is enabled, there may be additional exposure to the
server and client displays if the sshd proxy display is configured to listen
on the wildcard address. By default, sshd binds the forwarding server to the
loopback address and sets the hostname part of the DISPLAY
environment variable to localhost. This prevents remote hosts from
connecting to the proxy display.

To determine how the SSH daemon's X11UseLocalhost option is set, run the following command:

$ sudo grep -i X11UseLocalhost /etc/ssh/sshd_config

If a line indicating yes is returned, then the required value is set.
      Is it the case that the display proxy is listening on wildcard address?
      

The SSH daemon should prevent remote hosts from connecting to the proxy
display.

The default SSH configuration for X11UseLocalhost is yes,
which prevents remote hosts from connecting to the proxy display.

To explicitly prevent remote connections to the proxy display, add or correct
the following line in


/etc/ssh/sshd_config:

X11UseLocalhost yes
          

DoD information systems are required to use FIPS-approved key exchange algorithms.
The system will attempt to use the first algorithm presented by the client that matches
the server list. Listing the values "strongest to weakest" is a method to ensure the use
of the strongest algorithm available to secure the SSH connection.

Only FIPS-approved key exchange algorithms must be used. To verify that only FIPS-approved
key exchange algorithms are in use, run the following command:
$ sudo grep -i kexalgorithms /etc/ssh/sshd_config
The output should contain only following algorithms (or a subset) in the exact order:
KexAlgorithms ecdh-sha1-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256
      Is it the case that KexAlgorithms option is commented out, contains non-approved algorithms, or the FIPS-approved algorithms are not in the exact order?
      

Limit the key exchange algorithms to those  which are FIPS-approved.
Add or modify the following line in /etc/ssh/sshd_config
            KexAlgorithms ecdh-sha1-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256
This rule ensures that only the key exchange algorithms mentioned
above (or their subset) are configured for use, keeping the given
order of algorithms.

Using the -s option causes the TFTP service to only serve files from the
given directory. Serving files from an intentionally-specified directory
reduces the risk of sharing files which should remain private.

Verify the TFTP daemon is configured to operate in secure mode.

Check if a TFTP server is installed with the following command:

$ rpm -qa | grep tftp


If a TFTP server is not installed, this is Not Applicable.


If a TFTP server is installed, verify TFTP is configured by with
the -s option by running the following command:

grep "server_args" /etc/xinetd.d/tftp
server_args = -s 
      Is it the case that '"server_args" line does not have a "-s" option, and a subdirectory is not assigned'?
      

If running the Trivial File Transfer Protocol (TFTP) service is necessary,
it should be configured to change its root directory at startup. To do so,
ensure /etc/xinetd.d/tftp includes -s as a command line argument,
as shown in the following example:
server_args = -s 
            
          

Unnecessary service packages must not be installed to decrease the attack surface of the system. X windows has a long history of security
vulnerabilities and should not be installed unless approved and documented.

To ensure the X Windows package group is removed, run the following command:

$ rpm -qi xorg-x11-server-Xorg xorg-x11-server-common xorg-x11-server-utils

For each package mentioned above you should receive following line:
package  is not installed
      Is it the case that xorg related packages are not removed and run level is not correctly configured?
      

By removing the following packages,  the system no longer has X Windows installed.

xorg-x11-server-Xorg xorg-x11-server-common xorg-x11-server-utils

If X Windows is not installed then the system cannot boot into graphical user mode.
This prevents the system from being accidentally or maliciously booted into a graphical.target
mode. To do so, run the following command:

sudo yum remove xorg-x11-server-Xorg xorg-x11-server-common xorg-x11-server-utils
          

Routing protocol daemons are typically used on routers to exchange
network topology information with other routers. If this capability is used when
not required, system network information may be unnecessarily transmitted across
the network.

The runtime status of the net.ipv4.ip_forward kernel parameter can be queried
by running the following command:
$ sysctl net.ipv4.ip_forward
0.
The ability to forward packets is only appropriate for routers.
      Is it the case that the correct value is not returned?
      

To set the runtime status of the net.ipv4.ip_forward kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.ip_forward=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.ip_forward = 0
            

When an NFS server is configured to use AUTH_SYS a selected userid and groupid are used to handle
requests from the remote user. The userid and groupid could mistakenly or maliciously be set
incorrectly. The AUTH_GSS method of authentication uses certificates on the server and client
systems to more securely authenticate the remote mount request.

To verify the sec option is configured for all NFS mounts, run the following command:
$ mount | grep "sec="
All NFS mounts should show the sec=krb5:krb5i:krb5p setting in parentheses.
This is not applicable if NFS is not implemented.
      Is it the case that the setting is not configured, has the 'sys' option added, or does not have all Kerberos options added?
      

Add the sec=krb5:krb5i:krb5p option to the fourth column of /etc/fstab for the line which controls mounting of
any NFS mounts.

Whether active or not, default simple network management protocol (SNMP) community
strings must be changed to maintain security. If the service is running with the
default authenticators, then anyone can gather data about the system and the network
and use the information to potentially compromise the integrity of the system and
network(s).

To ensure the default password is not set, run the following command:
$ sudo grep -v "^#" /etc/snmp/snmpd.conf| grep -E 'public|private'
There should be no output.
      Is it the case that the default SNMP passwords public and private have not been changed or removed?
      

Edit /etc/snmp/snmpd.conf, remove or change the default community strings of
public and private.
This profile configures new read-only community string to 
              
             and read-write community string to 
              
            .
Once the default community strings have been changed, restart the SNMP service:
$ sudo systemctl restart snmpd
          

If the systems access control program is not configured with appropriate
rules for allowing and denying access to system network resources,
services may be accessible to unauthorized hosts.

To verify there is a system access control program configured
to grant or deny system access to specific hosts check to see
if "firewalld" is active and the default zone is "public".

If "firewalld" is not active, determine whether "tcpwrappers"
is being used by checking whether the "hosts.allow" and "hosts.deny"
files are empty.

If "firewalld" is not active and configured, and the "hosts.allow" and
"hosts.deny" files are empty, this is a finding.
      Is it the case that the system access control program is not configured?
      

To verify the system's access control program is configured
to grant or deny system access to specific hosts check to see
if "firewalld" is active with the following command:

# systemctl status firewalld
firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled)
Active: active (running) since Sun 2014-04-20 14:06:46 BST; 30s ago

If "firewalld" is active, check to see if it is configured to grant or deny
access to specific hosts or services with the following commands:

# firewall-cmd --get-default-zone
public

# firewall-cmd --list-all --zone=public
public (active)
target: default
icmp-block-inversion: no
interfaces: eth0
sources:
services: mdns ssh
ports:
protocols:
masquerade: no
forward-ports:
icmp-blocks:

If "firewalld" is not active, determine whether "tcpwrappers" is being used by checking
whether the "hosts.allow" and "hosts.deny" files are empty with the following commands:

# ls -al /etc/hosts.allow
rw-r----- 1 root root 9 Aug 2 23:13 /etc/hosts.allow

# ls -al /etc/hosts.deny
-rw-r----- 1 root root 9 Apr 9 2007 /etc/hosts.deny

If "firewalld" and "tcpwrappers" are not installed, configured, and active,
ask the SA if another access control program (such as iptables) is installed
and active.

Ask the SA to show that the running configuration grants or denies access
to specific hosts or services.

If "firewalld" is active and is not configured to grant access to specific
hosts or "tcpwrappers" is not configured to grant or deny access to
specific hosts, this is a finding.

IP tunneling mechanisms can be used to bypass network filtering.

Verify that Oracle Linux 7 does not have unauthorized IP tunnels configured.


# yum list installed libreswan
libreswan.x86-64 3.20-5.el7_4


If "libreswan" is installed, check to see if the "IPsec" service is active with the following command:

# systemctl status ipsec
ipsec.service - Internet Key Exchange (IKE) Protocol Daemon for IPsec
Loaded: loaded (/usr/lib/systemd/system/ipsec.service; disabled)
Active: inactive (dead)


If the "IPsec" service is active, check for configured IPsec connections (conn), perform the following:
grep -rni conn /etc/ipsec.conf /etc/ipsec.d/
Verify any returned results for organizational approval.
      Is it the case that the IPSec tunnels are not approved?
      

Libreswan provides an implementation of IPsec
and IKE, which permits the creation of secure tunnels over
untrusted networks. As such, IPsec can be used to circumvent certain
network requirements such as filtering. Verify that if any IPsec connection
(conn) configured in /etc/ipsec.conf and /etc/ipsec.d
exists is an approved organizational connection.

Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router, which can
be used to bypass network security measures. This requirement applies only to the
forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and
the system is functioning as a router.

              
Accepting source-routed packets in the IPv6 protocol has few legitimate
uses. It should be disabled unless it is absolutely required.

The runtime status of the net.ipv6.conf.all.accept_source_route kernel parameter can be queried
by running the following command:
$ sysctl net.ipv6.conf.all.accept_source_route
0.

      Is it the case that the correct value is not returned?
      

To set the runtime status of the net.ipv6.conf.all.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d: net.ipv6.conf.all.accept_source_route = 0
            

Using an authentication device, such as a CAC or token that is separate from
the information system, ensures that even if the information system is
compromised, that compromise will not affect credentials stored on the
authentication device.

                
Multifactor solutions that require devices separate from
information systems gaining access include, for example, hardware tokens
providing time-based or challenge-response authenticators and smart cards such
as the U.S. Government Personal Identity Verification card and the DoD Common
Access Card.

Check that Oracle Linux 7 has the packages for smart card support installed.

Run the following command to determine if the pam_pkcs11 package is installed:
$ rpm -q pam_pkcs11
      Is it the case that smartcard software is not installed?
      

Configure the operating system to implement multifactor authentication by
installing the required package with the following command:

The pam_pkcs11 package can be installed with the following command:

$ sudo yum install pam_pkcs11
              

Using an authentication device, such as a CAC or token that is separate from
the information system, ensures that even if the information system is
compromised, that compromise will not affect credentials stored on the
authentication device.

To verify that SSSD is configured for PAM services, run the following command:
$ sudo grep services /etc/sssd/sssd.conf
If configured properly, output should be similar to
services = pam
      Is it the case that it does not exist or 'pam' is not added to the 'services' option under the 'sssd' section?
      

SSSD should be configured to run SSSD pam services.
To configure SSSD to known SSH hosts, add pam
to services under the [sssd] section in
/etc/sssd/sssd.conf. For example:
[sssd]
services = sudo, autofs, pam

        

Using an authentication device, such as a CAC or token that is separate from
the information system, ensures that even if the information system is
compromised, that compromise will not affect credentials stored on the
authentication device.

                
Multifactor solutions that require devices separate from
information systems gaining access include, for example, hardware tokens
providing time-based or challenge-response authenticators and smart cards such
as the U.S. Government Personal Identity Verification card and the DoD Common
Access Card.

To verify the operating system implements certificate status checking for PKI
authentication, run the following command:
$ sudo grep -i cert_policy /etc/pam_pkcs11/pam_pkcs11.conf
The output should return multiple lines similiar to the following:
cert_policy = ca, ocsp_on, signature;
cert_policy = ca, ocsp_on, signature;
cert_policy = ca, ocsp_on, signature;
      Is it the case that ocsp_on is not configured?
      

Configure the operating system to do certificate status checking for PKI
authentication. Modify all of the cert_policy lines in
/etc/pam_pkcs11/pam_pkcs11.conf to include ocsp_on like so:
cert_policy = ca, ocsp_on, signature;
              

The use of wireless networking can introduce many different attack vectors into
the organization's network. Common attack vectors such as malicious association
and ad hoc networks will allow an attacker to spoof a wireless access point
(AP), allowing validated systems to connect to the malicious AP and enabling the
attacker to monitor and record network traffic. These malicious APs can also
serve to create a man-in-the-middle attack or be used to create a denial of
service to valid network resources.

Verify that there are no wireless interfaces configured on the system
with the following command:

Note: This requirement is Not Applicable for systems that do not have physical wireless network radios.

$ nmcli device status
DEVICE          TYPE      STATE         CONNECTION
virbr0          bridge    connected     virbr0
wlp7s0          wifi      connected     wifiSSID
enp6s0          ethernet  disconnected  --
p2p-dev-wlp7s0  wifi-p2p  disconnected  --
lo              loopback  unmanaged     --
virbr0-nic      tun       unmanaged     --
      Is it the case that a wireless interface is configured and has not been documented and approved by the Information System Security Officer (ISSO)?
      

Deactivating wireless network interfaces should prevent normal usage of the wireless
capability.

              

Configure the system to disable all wireless network interfaces with the following command:
$ sudo nmcli radio all off
            

If users can write to audit logs, audit trails can be modified or destroyed.

Run the following command to check the mode of the system audit logs:
$ sudo grep -iw log_file /etc/audit/auditd.conf
log_file=/var/log/audit/audit.log
$ sudo stat -c "%n %a" /var/log/audit/*
$ sudo ls -l /var/log/audit
Audit logs must be mode 0640 or less permissive.
      Is it the case that any permissions are more permissive?
      

Determine where the audit logs are stored with the following command:
$ sudo grep -iw log_file /etc/audit/auditd.conf
log_file = /var/log/audit/audit.log
Configure the audit log to be protected from unauthorized read access by setting the correct
permissive mode with the following command:
$ sudo chmod 0600 audit_log_file
          
By default, audit_log_file is "/var/log/audit/audit.log".