| CCE ID |
Rule Title |
Description |
Rationale |
Variable Setting |
NIST 800-53 Mapping |
|
Verify and Correct File Permissions with RPM |
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 --setperms PACKAGENAME
|
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. |
|
AC-6
AU-9(1)
AU-9(3)
CM-6(d)
CM-6(3)
|
|
Verify and Correct Ownership with RPM |
The RPM package management system can check file ownership
permissions of installed software packages, including many that are
important to system security. After locating a file with incorrect
permissions, which can be found with
rpm -Va | awk '{ if (substr($0,6,1)=="U" || substr($0,7,1)=="G") print $NF }'
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 --setugids PACKAGENAME
|
Ownership of binaries and configuration files that is incorrect
could allow an unauthorized user to gain privileges that they should
not have. The ownership set by the vendor should be maintained. Any
deviations from this baseline should be investigated. |
|
AC-6
AU-9(1)
AU-9(3)
CM-6(d)
CM-6(3)
|
|
Verify File Hashes with RPM |
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 match 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 | grep '^..5'
A "c" in the second column indicates that a file is a configuration file, which
may appropriately be expected to change. 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
|
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. |
|
CM-6(d)
CM-6(3)
SI-7(1)
|
|
Make sure that the dconf databases are up-to-date with regards to respective keyfiles |
By default, DConf uses a binary database as a data backend.
The system-level database is compiled from keyfiles in the /etc/dconf/db/ directory by the dconf update command. |
Unlike text-based keyfiles, the binary database is impossible to check by OVAL.
Therefore, in order to evaluate dconf configuration, both have to be true at the same time -
configuration files have to be compliant, and the database needs to be more recent than those keyfiles,
which gives confidence that it reflects them. |
|
|
|
Enable GNOME3 Login Warning Banner |
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/gdm.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/gdm.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. |
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. |
|
AC-8(a)
AC-8(b)
AC-8(c)(1)
AC-8(c)(2)
AC-8(c)(3)
|
|
Set the GNOME3 Login Warning Banner Text |
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 string 'APPROVED_BANNER'
where APPROVED_BANNER is the approved banner for your environment.
To enable, add or edit banner-message-text to
/etc/dconf/db/gdm.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/gdm.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. |
An appropriate warning message reinforces policy awareness during the logon
process and facilitates possible legal action against attackers. |
|
AC-8(a)
AC-8(b)
AC-8(c)
|
|
Modify the System Login 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.
|
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. |
|
AC-8(a)
AC-8(b)
AC-8(c)(1)
AC-8(c)(2)
AC-8(c)(3)
|
|
Enable GNOME3 Screensaver Lock After Idle Period |
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. |
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. |
|
AC-11(b)
|
|
Ensure Users Cannot Change GNOME3 Screensaver Lock After Idle Period |
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/00-security-settings.
For example:
/org/gnome/desktop/screensaver/lock-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. |
|
AC-11(b)
|
|
Enable the GNOME3 Login Smartcard Authentication |
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/gdm.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/gdm.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. |
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. |
|
|
|
Set GNOME3 Screensaver Inactivity Timeout |
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
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/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 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. |
|
AC-11(a)
|
|
Install the screen Package |
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 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. |
|
AC-11(a)
|
|
Enable GNOME3 Screensaver Idle Activation |
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 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. |
|
AC-11(a)
|
|
Ensure Users Cannot Change GNOME3 Screensaver Idle Activation |
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. |
|
AC-11(a)
|
|
Set GNOME3 Screensaver Lock Delay After Activation Period |
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
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/lock-delay
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. |
|
AC-11(a)
|
|
Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters |
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 reuiqred 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. |
|
IA-5(b)
IA-5(c)
IA-5(1)(a)
|
|
Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters |
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
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. |
|
IA-5(b)
IA-5(c)
IA-5(1)(a)
|
|
Ensure PAM Enforces Password Requirements - Minimum Digit Characters |
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 digits makes password guessing attacks more difficult by ensuring a larger
search space. |
|
IA-5(1)(a)
IA-5(b)
IA-5(c)
194
|
|
Ensure PAM Enforces Password Requirements - Minimum Special Characters |
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
possble 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. |
|
IA-5(b)
IA-5(c)
IA-5(1)(a)
|
|
Ensure PAM Enforces Password Requirements - Minimum Different Characters |
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 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. |
|
IA-5(b)
IA-5(c)
IA-5(1)(b)
|
|
Ensure PAM Enforces Password Requirements - Minimum Different Categories |
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.
Requiring a minimum number of character categories makes password guessing attacks more difficult
by ensuring a larger search space. |
|
IA-5
|
|
Set Password Maximum Consecutive Repeating Characters |
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 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. |
|
IA-5
IA-5(c)
|
|
Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating Characters from Same Character Class |
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. |
Use of a complex password helps to increase the time and resources required to comrpomise 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. |
|
IA-5
IA-5(c)
|
|
Set PAM's Password Hashing Algorithm |
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 execute
during a password change. Set the pam_unix.so module in the
password section to include the argument sha512, as shown
below:
password sufficient pam_unix.so sha512 other arguments...
This will help ensure when local users change their passwords, hashes for
the new passwords will be generated using the SHA-512 algorithm. This is
the default. |
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
kepy 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 ensures the use
of a strong hashing algorithm that makes password cracking attacks more
difficult. |
|
IA-5(b)
IA-5(c)
IA-5(1)(c)
IA-7
|
|
Set Password Hashing Algorithm in /etc/login.defs |
In /etc/login.defs, add or correct the following line to ensure
the system will use SHA-512 as the hashing algorithm:
ENCRYPT_METHOD SHA512
|
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. |
|
IA-5(b)
IA-5(c)
IA-5(1)(c)
IA-7
|
|
Set Password Hashing Algorithm in /etc/libuser.conf |
In /etc/libuser.conf, add or correct the following line in its
[defaults] section to ensure the system will use the SHA-512
algorithm for password hashing:
crypt_style = sha512
|
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
kepy 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 ensures the use
of a strong hashing algorithm that makes password cracking attacks more
difficult. |
|
IA-5(b)
IA-5(c)
IA-5(1)(c)
IA-7
|
|
Set Password Minimum Age |
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,
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. |
|
IA-5(f)
IA-5(1)(d)
|
|
Set Existing Passwords Minimum Age |
Configure non-compliant accounts to enforce a 24 hours/1 day minimum password
lifetime by running the following command:
$ sudo chage -m 1 USER
|
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. |
|
IA-5(1)(d)
|
|
Set Password Maximum Age |
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.
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. |
|
IA-5(f)
IA-5(g)
IA-5(1)(d)
|
|
Set Existing Passwords Maximum Age |
Configure non-compliant accounts to enforce a 60-day maximum password lifetime
restriction by running the following command:
$ sudo chage -M 60 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. |
|
IA-5(1)(d)
|
|
Limit Password Reuse |
Do not allow users to reuse recent passwords. This can be
accomplished by using the remember option for the pam_unix
or pam_pwhistory PAM modules.
In the file /etc/pam.d/system-auth, append remember=
to the line which refers to the pam_unix.so or pam_pwhistory.somodule, as shown below:
The DoD STIG requirement is 5 passwords. |
Preventing re-use of previous passwords helps ensure that a compromised password is not re-used by a user. |
|
IA-5(f)
IA-5(1)(e)
|
|
Ensure PAM Enforces Password Requirements - Minimum Length |
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. |
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
compromose the password. |
|
IA-5(1)(a)
|
|
Prevent Login to Accounts With Empty Password |
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
option in /etc/pam.d/system-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. |
|
AC-6
IA-5(b)
IA-5(c)
IA-5(1)(a)
|
|
Disable SSH Access via Empty Passwords |
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. |
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. |
|
AC-3
AC-6
AC-17(b)
CM-6(b)
|
|
Disable SSH Support for User Known Hosts |
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
|
Configuring this setting for the SSH daemon provides additional
assurance that remove login via SSH will require a password, even
in the event of misconfiguration elsewhere. |
|
AC-17(b)
|
|
Set Account Expiration Following Inactivity |
To specify the number of days after a password expires (which
signifies inactivity) until an account is permanently disabled, add or correct
the following lines in /etc/default/useradd, substituting
NUM_DAYS appropriately:
INACTIVE=
A value of 35 is recommended; however, this profile expects that the value is set to
useradd man page for more information. Determining the inactivity
timeout must be done with careful consideration of the length of a "normal"
period of inactivity for users in the particular environment. Setting
the timeout too low incurs support costs and also has the potential to impact
availability of the system to legitimate users. |
Disabling inactive accounts ensures that accounts which may not
have been responsibly removed are not available to attackers
who may have compromised their credentials. |
|
AC-2(2)
AC-2(3)
IA-4(e)
|
|
Set Lockout Time for Failed Password Attempts |
To configure the system to lock out accounts after a number of incorrect login
attempts and require an administrator to unlock the account using pam_faillock.so,
modify the content of both /etc/pam.d/system-auth and /etc/pam.d/password-auth as follows:
- add the following line immediately
before the pam_unix.so statement in the AUTH section:
auth required pam_faillock.so preauth silent deny= unlock_time= fail_interval=
- add the following line immediately
after the pam_unix.so statement in the AUTH section:
auth [default=die] pam_faillock.so authfail deny= unlock_time= fail_interval=
- add the following line immediately
before the pam_unix.so statement in the ACCOUNT section:
account required pam_faillock.so
If unlock_time is set to 0, manual intervention by an administrator is required to unlock a user. |
Locking out user accounts after a number of incorrect attempts
prevents direct password guessing attacks. Ensuring that an administrator is
involved in unlocking locked accounts draws appropriate attention to such
situations. |
|
AC-7(b)
|
|
Set Interval For Counting Failed Password Attempts |
Utilizing pam_faillock.so, the fail_interval directive
configures the system to lock out an account after a number of incorrect
login attempts within a specified time period. Modify the content of both
/etc/pam.d/system-auth and /etc/pam.d/password-auth
as follows:
- Add the following line immediately
before the
pam_unix.so statement in the AUTH section:
auth required pam_faillock.so preauth silent deny= unlock_time= fail_interval=
- Add the following line immediately
after the
pam_unix.so statement in the AUTH section:
auth [default=die] pam_faillock.so authfail deny= unlock_time= fail_interval=
- Add the following line immediately
before the
pam_unix.so statement in the ACCOUNT section:
account required pam_faillock.so
|
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. |
|
AC-7(a)
|
|
Set Deny For Failed Password Attempts |
To configure the system to lock out accounts after a number of incorrect login
attempts using pam_faillock.so, modify the content of both
/etc/pam.d/system-auth and /etc/pam.d/password-auth as follows:
- add the following line immediately
before the pam_unix.so statement in the AUTH section:
auth required pam_faillock.so preauth silent deny= unlock_time= fail_interval=
- add the following line immediately
after the pam_unix.so statement in the AUTH section:
auth [default=die] pam_faillock.so authfail deny= unlock_time= fail_interval=
- add the following line immediately
before the pam_unix.so statement in the ACCOUNT section:
account required pam_faillock.so
|
Locking out user accounts after a number of incorrect attempts
prevents direct password guessing attacks. |
|
AC-7(a)
|
|
Configure the root Account for Failed Password Attempts |
To configure the system to lock out the root account after a
number of incorrect login attempts using pam_faillock.so, modify
the content of both /etc/pam.d/system-auth and
/etc/pam.d/password-auth as follows:
|
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. |
|
AC-7(b)
|
|
Ensure Users Re-Authenticate for Privilege Escalation - sudo NOPASSWD |
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/. |
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. |
|
IA-11
|
|
Ensure the Logon Failure Delay is Set Correctly in login.defs |
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
|
Increasing the time between a failed authentication attempt and re-prompting to
enter credentials helps to slow a single-threaded brute force attack. |
|
AC-7(b)
CM-6(b)
|
|
Disable GDM Automatic 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. |
|
CM-6(b)
|
|
Disable GDM Guest Login |
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
|
Failure to restrict system access to authenticated users negatively impacts operating
system security. |
|
CM-6(b)
|
|
Do Not Allow SSH Environment Options |
To ensure users are not able to override environment
variables of the SSH daemon, add or correct the following line
in /etc/ssh/sshd_config:
PermitUserEnvironment no
|
SSH environment options potentially allow users to bypass
access restriction in some configurations. |
|
AC-17(b)
CM-6(b)
|
|
Disable Host-Based Authentication |
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.
To disable host-based authentication, add or correct the
following line in /etc/ssh/sshd_config:
HostbasedAuthentication no
|
SSH trust relationships mean a compromise on one host
can allow an attacker to move trivially to other hosts. |
|
AC-3
AC-17
CM-6(b)
|
|
Set Boot Loader Password in grub2 |
The grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.
To do so, select a superuser account name and password and and modify the
/etc/grub.d/01_users configuration file with the new account name.
Since plaintext passwords are a security risk, generate a hash for the pasword
by running the following command:
$ grub2-setpassword
When prompted, enter the password that was selected.
NOTE: It is recommended 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/root/bootuser/g /etc/grub.d/01_users
To meet FISMA Moderate, the bootloader superuser account and password MUST
differ from the root account and password.
Once the superuser account and password have been added,
update the
grub.cfg file by running:
grub2-mkconfig -o /boot/grub2/grub.cfg
NOTE: Do NOT manually add the superuser account and password to the
grub.cfg file as the grub2-mkconfig command overwrites this file. |
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. |
|
IA-2
IA-2(1)
IA-5(e)
AC-3
|
|
Require Authentication for Single User Mode |
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, no authentication
is performed if single-user mode is selected.
By default, single-user mode is protected by requiring a password and is set
in /usr/lib/systemd/system/rescue.service. |
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. |
|
IA-2
IA-2(1)
AC-3
|
|
Set the UEFI Boot Loader Password |
The grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.
To do so, select a superuser account name and password and and modify the
/etc/grub.d/01_users configuration file with the new account name.
Since plaintext passwords are a security risk, generate a hash for the pasword
by running the following command:
$ grub2-setpassword
When prompted, enter the password that was selected.
NOTE: It is recommended 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/root/bootuser/g /etc/grub.d/01_users
To meet FISMA Moderate, the bootloader superuser account and password MUST
differ from the root account and password.
Once the superuser account and password have been added,
update the
grub.cfg file by running:
grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
NOTE: Do NOT manually add the superuser account and password to the
grub.cfg file as the grub2-mkconfig command overwrites this file. |
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. |
|
AC-3
|
|
Enable Smart Card Login |
To enable smart card authentication, consult the documentation at:
|
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. |
|
IA-2(1)
|
|
Uninstall rsh-server Package |
The rsh-server package can be removed with the following command:
$ sudo yum erase rsh-server
|
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. |
|
AC-17(8)
CM-7(a)
|
|
Uninstall ypserv Package |
The ypserv package can be removed with the following command:
$ sudo yum erase ypserv
|
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. |
|
AC-17(8)
CM-7(a)
|
|
Map System Users To The Appropriate SELinux Role |
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. |
|
|
|
Install AIDE |
The aide package can be installed with the following command:
$ sudo yum install aide
|
The AIDE package must be installed if it is to be available for integrity checking. |
|
CM-3(d)
CM-3(e)
CM-6(d)
CM-6(3)
SC-28
SI-7
|
|
Configure Periodic Execution of AIDE |
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. |
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. |
|
CM-3(d)
CM-3(e)
CM-3(5)
CM-6(d)
CM-6(3)
SC-28
SI-7
|
|
Configure Notification of Post-AIDE 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. |
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. |
|
CM-3(5)
|
|
Ensure gpgcheck Enabled In Main yum Configuration |
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 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). |
|
CM-5(3)
CM-11
SI-7
MA-1(b)
|
|
Ensure gpgcheck Enabled for Local Packages |
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. |
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. |
|
CM-5(3)
CM-11
|
|
Disable Modprobe Loading of USB Storage Driver |
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 a file in the directory /etc/modprobe.d:
install usb-storage /bin/true
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. |
USB storage devices such as thumb drives can be used to introduce
malicious software. |
|
AC-19(a)
AC-19(d)
AC-19(e)
IA-3
MP-7
|
|
Disable DCCP Support |
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 a file in the directory /etc/modprobe.d:
install dccp /bin/true
|
Disabling DCCP protects
the system against exploitation of any flaws in its implementation. |
|
CM-7
|
|
Disable the Automounter |
The autofs daemon mounts and unmounts filesystems, such as user
home directories shared via NFS, on demand. In addition, autofs can be used to handle
removable media, and the default configuration provides the cdrom device as /misc/cd.
However, this method of providing access to removable media is not common, so autofs
can almost always be disabled if NFS is not in use. Even if NFS is required, it may be
possible to configure filesystem mounts statically by editing /etc/fstab
rather than relying on the automounter.
The autofs service can be disabled with the following command:
$ sudo systemctl disable autofs.service
The autofs service can be masked with the following command:
$ sudo systemctl mask autofs.service
|
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. |
|
AC-19(a)
AC-19(d)
AC-19(e)
IA-3
|
|
Ensure yum Removes Previous Package Versions |
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. |
Previous versions of software components that are not removed from the information
system after updates have been installed may be exploited by some adversaries. |
|
SI-2(6)
CM-11
|
|
Ensure SELinux State is Enforcing |
The SELinux state should be set to /etc/selinux/config, add or correct the
following line to configure the system to boot into enforcing mode:
SELINUX=
|
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. |
|
AC-3
AC-3(3)
AC-3(4)
AC-4
AC-6
AU-9
SI-6(a)
|
|
Disable Ctrl-Alt-Del Reboot Activation |
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. |
|
AC-6
|
|
Ensure the Default Umask is Set Correctly in login.defs |
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
|
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. |
|
CM-6(b)
SA-8
|
|
The Installed Operating System Is Vendor 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. |
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. |
|
SI-2(c)
|
|
Ensure Software Patches Installed |
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. |
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. |
|
SI-2
SI-2(c)
MA-1(b)
|
|
All GIDs referenced in /etc/passwd must be defined in /etc/group |
Add a group to the system for each GID referenced without a corresponding group. |
If a user is assigned the Group Identifier (GID) of a group not existing on the system, and a group
with the Gruop Identifier (GID) is subsequently created, the user may have unintended rights to
any files associated with the group. |
|
IA-2
|
|
Verify Only Root Has UID 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. |
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. |
|
AC-6
IA-2
IA-2(1)
IA-4
|
|
Ensure All Files Are Owned by a 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. |
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. 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. |
|
AC-3(4)
AC-6
CM-6(b)
|
|
Ensure All Files Are Owned by a Group |
If any files are not owned by a group, then the
cause of their lack of group-ownership should be investigated.
Following this, the files should be deleted or assigned to an
appropriate group. |
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. 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. |
|
AC-3(4)
AC-6
IA-2
|
|
All Interactive Users Must Have A Home Directory Defined |
Assign home directories to all interactive users that currently do not
have a home directory assigned. |
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. |
|
|
|
Ensure Home Directories are Created for New Users |
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 local interactive users are not assigned a valid home directory, there is no place
for the storage and control of files they should own. |
|
|
|
All Interactive Users Home Directories Must Exist |
Create home directories to all 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
|
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. |
|
|
|
All Interactive User Home Directories Must Have mode 0750 Or Less 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
|
Excessive permissions on local interactive user home directories may allow
unauthorized access to user files by other users. |
|
|
|
All Interactive User Home Directories Must Be Owned By The Primary User |
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
|
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. |
|
|
|
All Interactive User Home Directories Must Be Group-Owned By The Primary User |
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
|
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. |
|
|
|
All User Files and Directories In The Home Directory Must Be Owned By The Primary User |
Change the owner of a interactive users files and directories to that
owner. To change the of a local interactive users files and
directories, use the following command:
$ sudo chown -R USER /home/USER
|
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. |
|
|
|
All User Files and Directories In The Home Directory Must Be Group-Owned By The Primary User |
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
|
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. |
|
|
|
All User Files and Directories In The Home Directory Must Have Mode 0750 Or Less Permissive |
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
|
If a local interactive user files have excessive permissions, unintended users
may be able to access or modify them. |
|
|
|
User Initialization Files Must Be Owned By the Primary User |
Set the owner of the user initialization files for interactive users to
the primary owner with the following command:
$ sudo chown USER /home/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. |
|
|
|
User Initialization Files Must Be Group-Owned By The Primary User |
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
|
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. |
|
|
|
Ensure All User Initialization Files Have Mode 0740 Or Less Permissive |
Set the mode of the user initialization files to 0740 with the
following command:
$ sudo chmod 0740 /home/USER/.INIT_FILE
|
Local initialization files are used to configure the user's shell environment
upon logon. Malicious modification of these files could compromise accounts upon
logon. |
|
|
|
Ensure that Users Path Contains Only Local Directories |
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. |
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). |
|
|
|
User Initialization Files Must Not Run World-Writable Programs |
Set the mode on files being executed by the user initialization files with the
following command:
$ sudo chmod 0755 FILE
|
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. |
|
|
|
Ensure No Device Files are Unlabeled by SELinux |
Device files, which are used for communication with important system
resources, should be labeled with proper SELinux types. If any device
files do not carry the SELinux type device_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 unlabeled device files, run the following command:
$ sudo find /dev -context *:device_t:* \( -type c -o -type b \) -printf "%p %Z\n"
It should produce no output in a well-configured system. |
If a device file carries the SELinux type device_t, then SELinux
cannot properly restrict access to the device file. |
|
AC-6
AU-9
CM-3(f)
CM-7
|
|
Add nosuid Option to /home |
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. Users
should not be able to execute SUID or SGID binaries from user home directory partitions. |
|
CM-7
MP-2
|
|
Add nosuid Option to Removable Media Partitions |
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. |
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. |
|
AC-6
AC-19(a)
AC-19(d)
AC-19(e)
CM-7
MP-2
|
|
Mount Remote Filesystems with nosuid |
Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of
any NFS mounts. |
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. |
|
AC-6
|
|
Add nodev Option to /dev/shm |
The nodev mount option can be used to prevent creation of device
files in /dev/shm. Legitimate character and block devices should
not exist within temporary directories like /dev/shm.
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm. |
The only legitimate location for device files is the /dev directory
located on the root partition. The only exception to this is chroot jails. |
|
CM-7
MP-2
|
|
Add noexec Option to /dev/shm |
The noexec mount option can be used to prevent binaries
from being executed out of /dev/shm.
It can be dangerous to allow the execution of binaries
from world-writable temporary storage directories such as /dev/shm.
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm. |
Allowing users to execute binaries from world-writable directories
such as /dev/shm can expose the system to potential compromise. |
|
CM-7
MP-2
|
|
Add nosuid Option to /dev/shm |
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. |
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. |
|
CM-7
MP-2
|
|
Ensure All World-Writable Directories Are Owned by a System Account |
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 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. |
|
AC-6
|
|
Ensure the Default Umask is Set Correctly For Interactive Users |
Remove the UMASK environment variable from all interactive users initialization files. |
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. |
|
|
|
Ensure cron Is 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:
cron.* /var/log/cron
|
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. |
|
AU-2(d)
|
|
Verify User Who Owns /etc/cron.allow file |
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. |
|
AC-6
|
|
Verify Group Who Owns /etc/cron.allow file |
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
|
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. |
|
AC-6
|
|
Disable KDump Kernel Crash Analyzer (kdump) |
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 disable kdump.service
The kdump service can be masked with the following command:
$ sudo systemctl mask kdump.service
|
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. |
|
AC-17(8)
CM-7
CM-6(b)
|
|
Ensure /home Located On Separate Partition |
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 /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. |
|
SC-32(1)
|
|
Ensure /var Located On Separate Partition |
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. |
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. |
|
SC-32(1)
|
|
Ensure /var/log/audit Located On Separate Partition |
Audit logs are stored in the /var/log/audit directory. Ensure that it
has its own partition or logical volume at installation time, or migrate it
later using LVM. Make absolutely certain that it is large enough to store all
audit logs that will be created by the auditing daemon. |
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. |
|
AU-4
AU-9
SC-32(1)
|
|
Ensure /tmp Located On Separate Partition |
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. |
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. |
|
SC-32(1)
|
|
Enable FIPS Mode in GRUB2 |
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:
|
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. |
|
IA-5
SC-13
AC-17(2)
IA-7
|
|
Configure AIDE to Verify Access Control Lists (ACLs) |
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. |
ACLs can provide permissions beyond those permitted through the file mode and must be
verified by the file integrity tools. |
|
SI-7.1
|
|
Configure AIDE to Verify Extended Attributes |
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. |
Extended attributes in file systems are used to contain arbitrary data and file metadata
with security implications. |
|
SI-7.1
|
|
Configure AIDE to Use FIPS 140-2 for Validating Hashes |
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. |
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. |
|
SI-7(1)
|
|
Boat Loader Is Not Installed On Removeable Media |
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 line:
set root='hd0,msdos1'
|
Malicious users with removable boot media can gain access to a system
configured to use removable media as the boot loader. |
|
|
|
Uninstall telnet-server Package |
The telnet-server package can be removed with the following command:
$ sudo yum erase telnet-server
|
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. |
|
AC-17(8)
CM-7(a)
|
|
Enable auditd Service |
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
|
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. |
|
AC-2(g)
AU-3
AC-17(1)
AU-1(b)
AU-10
AU-12(a)
AU-12(c)
AU-14(1)
IR-5
|
|
System Audit Logs Must Have Mode 0640 or Less Permissive |
If log_group in /etc/audit/auditd.conf is set to a group other than the root
group account, change the mode of the audit log files with the following command:
$ sudo chmod 0640 audit_file
Otherwise, change the mode of the audit log files with the following command:
$ sudo chmod 0600 audit_file
|
If users can write to audit logs, audit trails can be modified or destroyed. |
|
AC-6
AU-1(b)
AU-9
IR-5
|
|
System Audit Logs Must Be Owned By Root |
All audit logs must be owned by root user and group. By default, the path for audit log is /var/log/audit/ .
To properly set the owner of /var/log/audit, run the command:
$ sudo chown root /var/log/audit
To properly set the owner of /var/log/audit/*, run the command:
$ sudo chown root /var/log/audit/*
|
Unauthorized disclosure of audit records can reveal system and configuration data to
attackers, thus compromising its confidentiality. |
|
AC-6
AU-1(b)
AU-9
IR-5
|
|
Shutdown System When Auditing Failures Occur |
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:
-f 2
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to the
top of the /etc/audit/audit.rules file:
-f 2
|
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. |
|
AU-5
AU-5(b)
|
|
Configure audispd Plugin To Send Logs To Remote Server |
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 replacing REMOTE_SYSTEM with an IP
address or hostname:
remote_server = REMOTE_SYSTEM
|
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. |
|
|
|
Encrypt Audit Records Sent With audispd Plugin |
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
|
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. |
|
|
|
Configure audispd's Plugin disk_full_action When Disk Is Full |
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 in case of a filled audit storage volume will
minimize the possibility of losing audit records. |
|
AU-5(b)
AU-5(2)
AU-5(1)
AU-5(4)
CM-6(a)
|
|
Set hostname as computer node name in audit logs |
To configure Audit daemon to use value returned by gethostname
syscall as computer node name in the audit events,
set name_format to hostname
in /etc/audit/auditd.conf. |
If option name_format is left at its default value of
none, audit events from different computers may be hard
to distinguish. |
|
|
|
Configure auditd space_left on Low Disk Space |
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 SIZE_in_MB appropriately:
space_left = SIZE_in_MB
Set this value to the appropriate size in Megabytes 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. |
|
AU-1(b)
AU-4
AU-5(b)
IR-5
AU-5(1)
|
|
Configure auditd space_left Action on Low Disk Space |
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:
syslogemailexecsuspendsinglehalt
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. |
Notifying administrators of an impending disk space problem may
allow them to take corrective action prior to any disruption. |
|
AU-1(b)
AU-4
AU-5(1)
AU-5(b)
IR-5
|
|
Configure auditd mail_acct Action on Low Disk Space |
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 =
|
Email sent to the root account is typically aliased to the
administrators of the system, who can take appropriate action. |
|
AU-1(b)
AU-4
AU-5(1)
AU-5(a)
IR-5
|
|
Ensure auditd Collects Information on the Use of Privileged Commands |
At a minimum, the audit system should collect the execution of
privileged commands for all users and root. To find the relevant setuid /
setgid programs, run the following command for each local partition
PART:
$ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null
If the auditd daemon is configured to use the augenrules
program to read audit rules during daemon startup (the default), add a line of
the following form to a file with suffix .rules in the directory
/etc/audit/rules.d for each setuid / setgid program on the system,
replacing the SETUID_PROG_PATH part with the full path of that setuid /
setgid program in the list:
-a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules for each setuid / setgid program on the
system, replacing the SETUID_PROG_PATH part with the full path of that
setuid / setgid program in the list:
-a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
|
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 threast.
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-2(4)
AU-6(9)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - chown |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=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 chown -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 chown -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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - fchown |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=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 fchown -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 fchown -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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - lchown |
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - fchownat |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=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 fchownat -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 fchownat -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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - chmod |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=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 chmod -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 chmod -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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - fchmod |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=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 fchmod -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 fchmod -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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - fchmodat |
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - setxattr |
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
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - fsetxattr |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=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 fsetxattr -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 fsetxattr -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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - lsetxattr |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=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 lsetxattr -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 lsetxattr -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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - removexattr |
At a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured to use the augenrules
program to read audit rules during daemon startup (the default), add the
following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=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 removexattr -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 removexattr -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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - fremovexattr |
At a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=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 fremovexattr -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 fremovexattr -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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify the System's Discretionary Access Controls - lremovexattr |
At a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=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 lremovexattr -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 lremovexattr -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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Unsuccessful Access Attempts to Files - creat |
At a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -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 creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -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 creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -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 creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Unsuccessful Access Attempts to Files - open |
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 open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -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 open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -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 open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -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 open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Unsuccessful Access Attempts to Files - openat |
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 openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -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 openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -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 openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -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 openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Unsuccessful Access Attempts to Files - open_by_handle_at |
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 open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open_by_handle_at -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 open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open_by_handle_at -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 open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open_by_handle_at,truncate,ftruncate -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 open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Unsuccessful Access Attempts to Files - truncate |
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
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Unsuccessful Access Attempts to Files - ftruncate |
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 ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -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 ftruncate -F exiu=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -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 ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -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 ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Any Attempts to Run semanage |
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-priv_change
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-priv_change
|
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 threast.
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. |
|
AU-12(c)
|
|
Record Any Attempts to Run setsebool |
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-priv_change
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-priv_change
|
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 threast.
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. |
|
AU-12(c)
|
|
Record Any Attempts to Run chcon |
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-priv_change
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-priv_change
|
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 threast.
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. |
|
AU-12(c)
|
|
Record Any Attempts to Run setfiles |
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-priv_change
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-priv_change
|
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 threast.
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. |
|
AU-12(c)
|
|
Record Attempts to Alter Logon and Logout Events - faillock |
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/run/faillock -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/run/faillock -p wa -k logins
|
Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. |
|
AC-17(7)
AU-1(b)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Attempts to Alter Logon and Logout Events - lastlog |
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
|
Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. |
|
AC-17(7)
AU-1(b)
AU-12(a)
AU-12(c)
IR-5
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - passwd |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - unix_chkpwd |
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/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
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/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - gpasswd |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - chage |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - userhelper |
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/userhelper -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
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/userhelper -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - su |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - sudo |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects System Administrator Actions |
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
|
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. |
|
AC-2(7)(b)
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-3(1)
AU-12(a)
AU-12(c)
IR-5
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - newgrp |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - chsh |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on Exporting to Media (successful) |
At a minimum, the audit system should collect media exportation
events for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export
|
The unauthorized exportation of data to external media could result in an information leak
where classified information, Privacy Act information, and intellectual property could be lost. An audit
trail should be created each time a filesystem is mounted to help identify and guard against information
loss. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-3(1)
AU-12(a)
AU-12(c)
IR-5
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - umount |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - postdrop |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - postqueue |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - ssh-keysign |
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=special-config-changes
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/key-sign -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - crontab |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - pam_timestamp_check |
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=special-config-changes
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=special-config-changes
|
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 threast.
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. |
|
AU-3(1)
AU-12(c)
|
|
Ensure auditd Collects Information on Kernel Module Loading - init_module |
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 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 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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Ensure auditd Collects Information on Kernel Module Loading and Unloading - finit_module |
If the auditd daemon is configured to use the augenrules program
to read audit rules during daemon startup (the default), add the following lines to a file
with suffix .rules in the directory /etc/audit/rules.d to capture kernel module
loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S finit_module -F key=modules
If the auditd daemon is configured to use the auditctl utility to read audit
rules during daemon startup, add the following lines to /etc/audit/audit.rules file
in order to capture kernel module loading and unloading events, setting ARCH to either b32 or
b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S finit_module -F key=modules
|
The addition/removal of kernel modules can be used to alter the behavior of
the kernel and potentially introduce malicious code into kernel space. It is important
to have an audit trail of modules that have been introduced into the kernel. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Ensure auditd Collects Information on Kernel Module Unloading - delete_module |
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 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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify User/Group Information - /etc/passwd |
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. |
|
AC-2(4)
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Ensure auditd Collects File Deletion Events by User - rename |
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 rename -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 rename -F auid>=1000 -F auid!=unset -F key=delete
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
MA-4(1)(a)
|
|
Ensure auditd Collects File Deletion Events by User - renameat |
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 renameat -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 renameat -F auid>=1000 -F auid!=unset -F key=delete
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
MA-4(1)(a)
|
|
Ensure auditd Collects File Deletion Events by User - rmdir |
At a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir -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 rmdir -F auid>=1000 -F auid!=unset -F key=delete
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
MA-4(1)(a)
|
|
Ensure auditd Collects File Deletion Events by User - unlink |
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 unlink -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 unlink -F auid>=1000 -F auid!=unset -F key=delete
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
MA-4(1)(a)
|
|
Ensure auditd Collects File Deletion Events by User - unlinkat |
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
|
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. |
|
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
MA-4(1)(a)
|
|
Ensure Logs Sent To Remote Host |
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 loghost.example.com 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:
*.* @loghost.example.com
To use TCP for log message delivery:
*.* @@loghost.example.com
To use RELP for log message delivery:
*.* :omrelp:loghost.example.com
There must be a resolvable DNS CNAME or Alias record set to "" for logs to be sent correctly to the centralized logging utility. |
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. |
|
AU-3(2)
AU-4(1)
AU-9
|
|
Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server |
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 the following lines are
not found in /etc/rsyslog.conf:
$ModLoad imtcp
$InputTCPServerRun port
$ModLoad imudp
$UDPServerRun port
$ModLoad imrelp
$InputRELPServerRun port
|
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. |
|
AU-9(2)
AC-4
CM-6(c)
|
|
Install Virus Scanning Software |
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. |
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. |
|
SC-28
SI-3
SI-3(1)(ii)
|
|
Limit the Number of Concurrent Login Sessions Allowed Per User |
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:
* hard maxlogins
|
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. |
|
AC-10
|
|
Configure the Firewalld Ports |
Configure the firewalld ports to allow approved
services to have access to the system. To configure firewalld
to open ports, run the following command:
$ sudo firewall-cmd --permanent --add-port=port_number/tcp
or
$ sudo firewall-cmd --permanent --add-port=service_name
Run the command list above for each of the ports listed below:
To configure firewalld to allow access, run the following command(s):
firewall-cmd --permanent --add-service=ssh
|
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 any 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 or to address authorized quality of life issues. |
|
CM-7
CM-7.1(iii)
CM-7(b)
AC-17(1)
|
|
Use Only FIPS 140-2 Validated Ciphers |
Limit the ciphers to those algorithms which are FIPS-approved.
Counter (CTR) mode is also preferred over cipher-block chaining (CBC) mode.
The following line in /etc/ssh/sshd_config
demonstrates use of FIPS-approved ciphers:
Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
The man page sshd_config(5) contains a list of supported ciphers.
The following ciphers are FIPS 140-2 certified on Oracle Linux 7:
- aes128-ctr
- aes192-ctr
- aes256-ctr
- aes128-cbc
- aes192-cbc
- aes256-cbc
- 3des-cbc
- rijndael-cbc@lysator.liu.se
Any combination of the above ciphers will pass this check.
Official FIPS 140-2 paperwork for Oracle Linux 7 can be found at
https://csrc.nist.gov/CSRC/media/projects/cryptographic-module-validation-program/documents/security-policies/140sp3028.pdf
|
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. |
|
AC-3
AC-17(b)
AC-17(2)
AU-10(5)
CM-6(b)
IA-5(1)(c)
IA-7
SI-7
SC-13
|
|
Set Interactive Session Timeout |
Setting the TMOUT option in /etc/profile ensures that
all user sessions will terminate based on inactivity. The TMOUT
setting in /etc/profile should read as follows:
TMOUT=
|
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. |
|
AC-12
SC-10
|
|
Enable SSH Warning Banner |
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. |
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. |
|
AC-8(a)
AC-8(b)
AC-8(c)(1)
AC-8(c)(2)
AC-8(c)(3)
AC-17(b)
|
|
Configure SSSD LDAP Backend to Use TLS For All Transactions |
This check verifies that Oracle Linux 7 implements cryptography
to protect the integrity of remote LDAP authentication sessions.
To determine if LDAP is being used for authentication, use the following
command:
$ sudo grep -i useldapauth /etc/sysconfig/authconfig
If USELDAPAUTH=yes, then LDAP is being used. To check if LDAP is
configured to use TLS, use the following command:
$ sudo grep -i ldap_id_use_start_tls /etc/sssd/sssd.conf
|
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. |
|
AC-17(2)
CM-7
|
|
Configure SSSD LDAP Backend Client CA Certificate Location |
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
|
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. |
|
|
|
Configure SSSD LDAP Backend Client CA Certificate |
Configure SSSD to implement cryptography to protect the
integrity of LDAP remote access sessions. By setting
the ldap_tls_cacert option in /etc/sssd/sssd.conf
to point to the path for the X.509 certificates used for peer authentication.
ldap_tls_cacert /path/to/tls/ca.cert
|
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. |
|
|
|
Enable Randomized Layout of Virtual Address Space |
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
If this is not the system default value, add the following line to a file in the directory /etc/sysctl.d: kernel.randomize_va_space = 2
|
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. |
|
SC-30(2)
SC-39
|
|
Install the OpenSSH Server Package |
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. |
|
SC-8
|
|
Enable the OpenSSH Service |
The SSH server service, sshd, is commonly needed.
The sshd service can be enabled with the following command:
$ sudo systemctl enable sshd.service
|
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. |
|
SC-8
|
|
Set SSH Idle Timeout Interval |
SSH allows administrators to set an idle timeout
interval.
After this interval has passed, the idle user will be
automatically logged out.
To set an idle timeout interval, edit the following line in /etc/ssh/sshd_config as
follows:
ClientAliveInterval
The timeout interval is given in seconds. To have a timeout
of e.g. 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 here. Keep in mind that some processes may stop SSH
from correctly detecting that the user is idle. |
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. |
|
AC-2(5)
SA-8(i)
AC-12
AC-17(b)
SC-10
|
|
Disable SSH Support for .rhosts Files |
SSH can emulate the behavior of the obsolete rsh
command in allowing users to enable insecure access to their
accounts via .rhosts files.
To ensure this behavior is disabled, add or correct the
following line in /etc/ssh/sshd_config:
IgnoreRhosts yes
|
SSH trust relationships mean a compromise on one host
can allow an attacker to move trivially to other hosts. |
|
AC-3
AC-17(b)
CM-6(a)
|
|
Disable SSH Support for Rhosts RSA Authentication |
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
|
Configuring this setting for the SSH daemon provides additional
assurance that remove login via SSH will require a password, even
in the event of misconfiguration elsewhere. |
|
CM-6(a)
AC-17(b)
|
|
Set SSH Client Alive Max Count |
To ensure the SSH idle timeout occurs precisely when the ClientAliveInterval is set,
edit /etc/ssh/sshd_config as follows:
ClientAliveCountMax
|
This ensures a user login will be terminated as soon as the ClientAliveInterval
is reached. |
|
AC-2(5)
SA-8
AC-12
AC-17(b)
SC-10
|
|
Enable SSH Print Last Log |
When enabled, SSH will display the date and time of the last
successful account logon. To enable LastLog in
SSH, add or correct the following line in the /etc/ssh/sshd_config file:
PrintLastLog yes
|
Providing users feedback on when account accesses last occurred facilitates user
recognition and reporting of unauthorized account use. |
|
AC-9
AC-17(b)
|
|
Disable SSH Root Login |
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
|
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. |
|
AC-3
AC-6(2)
AC-17(b)
IA-2
IA-2(5)
|
|
Allow Only SSH 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
|
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. |
|
AC-17(b)
AC-17(8).1(ii)
IA-5(1)(c)
|
|
Use Only FIPS 140-2 Validated MACs |
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,hmac-sha1
The man page sshd_config(5) contains a list of supported MACs.
Only the following message authentication codes are FIPS 140-2 certified on Oracle Linux 7:
- hmac-sha1
- hmac-sha2-256
- hmac-sha2-512
- hmac-sha1-etm@openssh.com
- hmac-sha2-256-etm@openssh.com
- hmac-sha2-512-etm@openssh.com
Any combination of the above MACs will pass this check. Official FIPS 140-2 paperwork for
Oracle Linux 7 can be found at
https://csrc.nist.gov/CSRC/media/projects/cryptographic-module-validation-program/documents/security-policies/140sp3028.pdf
|
DoD Information Systems are required to use FIPS-approved cryptographic hash
functions. The only SSHv2 hash algorithms meeting this requirement is SHA2. |
|
AC-17(b)
AC-17(2)
IA-7
SC-13
MA-4(6)
|
|
Verify Permissions on SSH Server Public *.pub Key Files |
To properly set the permissions of /etc/ssh/*.pub, run the command: $ sudo chmod 0644 /etc/ssh/*.pub
|
If a public host key file is modified by an unauthorized user, the SSH service
may be compromised. |
|
AC-6
|
|
Verify Permissions on SSH Server Private *_key Key Files |
To properly set the permissions of /etc/ssh/*_key, run the command:
$ sudo chmod 0640 /etc/ssh/*_key
|
If an unauthorized user obtains the private SSH host key file, the host could be
impersonated. |
|
AC-6
AC-17
|
|
Disable GSSAPI Authentication |
Unless needed, SSH should not permit extraneous or unnecessary
authentication mechanisms like GSSAPI. To disable GSSAPI authentication, add or
correct the following line in the /etc/ssh/sshd_config file:
GSSAPIAuthentication no
|
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. |
|
AC-17(b)
CM-6(c)
|
|
Disable Kerberos Authentication |
Unless needed, SSH should not permit extraneous or unnecessary
authentication mechanisms like Kerberos. To disable Kerberos authentication, add
or correct the following line in the /etc/ssh/sshd_config file:
KerberosAuthentication 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. Vulnerabilities in the system's Kerberos
implementations may be subject to exploitation. |
|
CM-6(c)
|
|
Enable Use of Strict Mode Checking |
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. To enable StrictModes in SSH,
add or correct the following line in the /etc/ssh/sshd_config file:
StrictModes yes
|
If other users have access to modify user-specific SSH configuration files, they
may be able to log into the system as another user. |
|
AC-6
AC-17(b)
|
|
Enable Use of Privilege Separation |
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
|
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. |
|
AC-6
AC-17(b)
|
|
Disable Compression Or Set Compression to 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
|
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 wih root privileges. |
|
CM-6(b)
|
|
Configure Time Service Maxpoll Interval |
The maxpoll should be configured to
in /etc/ntp.conf or
/etc/chrony.conf to continuously poll time servers. To configure
maxpoll in /etc/ntp.conf or /etc/chrony.conf
add the following:
maxpoll
|
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. |
|
AU-8(1)(a)
|
|
Configure firewalld To Rate Limit Connections |
Create a direct firewall rule to protect against DoS attacks with the following
command:
$ sudo firewall-cmd --permanent --direct --add-rule ipv4 filter INPUT_direct 0 -p tcp -m limit --limit 25/minute --limit-burst 100 -j ACCEPT
|
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 requirement addresses the configuration of
the operating system to mitigate the impact of DoS attacks that have occurred or
are ongoing on system availability. For each system, known and potential DoS
attacks must be identified and solutions for each type implemented. A variety of
technologies exist to limit or, in some cases, eliminate the effects of DoS
attacks (e.g., limiting processes or establishing memory partitions). Employing
increased capacity and bandwidth, combined with service redundancy, may reduce
the susceptibility to some DoS attacks. |
|
SC-5
|
|
Verify firewalld Enabled |
The firewalld service can be enabled with the following command: $ sudo systemctl enable firewalld.service
|
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. |
|
CM-6(b)
|
|
Ensure PAM Displays Last Logon/Access Notification |
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 read as follows:
session [success=1 default=ignore] pam_succeed_if.so service !~ gdm* service !~ su* quiet
session [default=1] pam_lastlog.so nowtmp showfailed
session optional pam_lastlog.so silent noupdate showfailed
|
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. |
|
AC-9
|
|
Remove User Host-Based Authentication Files |
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 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. |
|
|
|
Remove Host-Based Authentication Files |
The shosts.equiv file 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 rm /[path]/[to]/[file]/shosts.equiv
|
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. |
|
|
|
Configure Multiple DNS Servers in /etc/resolv.conf |
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
|
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. |
|
SC-22
|
|
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv4 Interfaces |
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
If this is not the system default value, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.all.accept_source_route = 0
|
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. |
|
AC-4
CM-7
SC-5
|
|
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv4 Interfaces by Default |
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
If this is not the system default value, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.default.accept_source_route = 0
|
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. |
|
AC-4
CM-7
SC-5
SC-7
|
|
Enable Kernel Parameter to Ignore ICMP Broadcast Echo Requests on IPv4 Interfaces |
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
If this is not the system default value, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.icmp_echo_ignore_broadcasts = 1
|
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. |
|
AC-4
CM-7
SC-5
|
|
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv4 Interfaces |
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
If this is not the system default value, 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. |
|
AC-4
CM-7
SC-5
SC-7
|
|
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces by Default |
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
If this is not the system default value, 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. |
|
AC-4
CM-7
SC-5
SC-7
|
|
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces |
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
If this is not the system default value, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.all.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. |
|
AC-4
CM-7
SC-5(1)
|
|
Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces |
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
If this is not the system default value, 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. |
|
AC-4
SC-5
SC-7
|
|
Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces by Default |
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
If this is not the system default value, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.conf.default.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. |
|
AC-4
SC-5
SC-7
|
|
Ensure System is Not Acting as a Network Sniffer |
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
|
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. |
|
CM-7
CM-7(2).1(i)
MA-3
|
|
Prevent Unrestricted Mail Relaying |
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'
|
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. |
|
|
|
Uninstall vsftpd Package |
The vsftpd package can be removed with the following command: $ sudo yum erase vsftpd
|
Removing the vsftpd package decreases the risk of its
accidental activation. |
|
CM-6(b)
CM-7
|
|
Uninstall tftp-server Package |
The tftp-server package can be removed with the following command: $ sudo yum erase tftp-server
|
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. |
|
AC-17(8)
CM-6(c)
CM-7
|
|
Enable Encrypted X11 Forwarding |
By default, remote X11 connections are not encrypted when initiated
by users. SSH has the capability to encrypt remote X11 connections when SSH's
X11Forwarding option is enabled.
To enable X11 Forwarding, add or correct the
following line in /etc/ssh/sshd_config:
X11Forwarding yes
|
Open X displays allow an attacker to capture keystrokes and to execute commands
remotely. |
|
CM-2(1)(b)
|
|
Ensure tftp Daemon Uses Secure Mode |
If running the 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 (which is also the default):
server_args = -s /var/lib/tftpboot
|
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. |
|
AC-6
AC-17(8)
CM-7
|
|
Remove the X Windows Package Group |
By removing the xorg-x11-server-common package, the system no longer has X Windows
installed. 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 groupremove "X Window System"
$ sudo yum remove xorg-x11-server-common
|
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. |
|
AC-17(8).1(ii)
|
|
Disable Kernel Parameter for IP Forwarding on IPv4 Interfaces |
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
If this is not the system default value, add the following line to a file in the directory /etc/sysctl.d: net.ipv4.ip_forward = 0
|
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. |
|
CM-7
SC-5
SC-32
|
|
Mount Remote Filesystems with Kerberos Security |
Add the sec=krb5:krb5i:krb5p option to the fourth column of /etc/fstab for the line which controls mounting of
any NFS mounts. |
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. |
|
AC-14(1)
|
|
Ensure Default SNMP Password Is Not Used |
Edit /etc/snmp/snmpd.conf, remove or change the default community strings of
public and private.
Once the default community strings have been changed, restart the SNMP service:
$ sudo service snmpd restart
|
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). |
|
IA-5.1(ii)
|
|
Set Default firewalld Zone for Incoming Packets |
To set the default zone to drop for
the built-in default zone which processes incoming IPv4 and IPv6 packets,
modify the following line in
/etc/firewalld/firewalld.conf to be:
DefaultZone=drop
|
In firewalld the default zone is applied only after all
the applicable rules in the table are examined for a match. Setting the
default zone to drop implements proper design for a firewall, i.e.
any packets which are not explicitly permitted should not be
accepted. |
|
CM-6(b)
CM-7
|
|
Verify Any Configured IPSec Tunnel Connections |
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. |
IP tunneling mechanisms can be used to bypass network filtering. |
|
AC-4
|
|
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv6 Interfaces |
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
If this is not the system default value, add the following line to a file in the directory /etc/sysctl.d: net.ipv6.conf.all.accept_source_route = 0
|
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. |
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AC-4
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Install Smart Card Packages For Multifactor Authentication |
Configure the operating system to implement multifactor authentication by
installing the required packages with the following command:
The esc pam_pkcs11 package can be installed with the following command:
$ sudo yum install esc pam_pkcs11
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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. |
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CM-6(a)
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Configure PAM in SSSD Services |
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
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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. |
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IA-2(11)
|
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Configure Smart Card Certificate Status Checking |
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;
|
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. |
|
|
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Ensure Users Cannot Change GNOME3 Screensaver Settings |
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. |
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AC-11(a)
|
|
Ensure Users Cannot Change GNOME3 Session Idle Settings |
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 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. |
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AC-11(a)
|
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Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted Per-Session |
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. |
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. |
|
CM-6(b)
IA-5(c)
|
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Mount Remote Filesystems with noexec |
Add the noexec 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. |
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AC-6
|
|
Configure audispd's Plugin network_failure_action On Network Failure |
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. |
Taking appropriate action when there is an error sending audit records to a
remote system will minimize the possibility of losing audit records. |
|
AU-5(b)
AU-5(2)
AU-5(1)
AU-5(4)
CM-6(a)
|
|
Record Events that Modify User/Group Information - /etc/group |
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. |
|
AC-2(4)
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify User/Group Information - /etc/gshadow |
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. |
|
AC-2(4)
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify User/Group Information - /etc/shadow |
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. |
|
AC-2(4)
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Record Events that Modify User/Group Information - /etc/security/opasswd |
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
|
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. |
|
AC-2(4)
AC-17(7)
AU-1(b)
AU-2(a)
AU-2(c)
AU-2(d)
AU-12(a)
AU-12(c)
IR-5
|
|
Disable Accepting ICMP Redirects for All IPv4 Interfaces |
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
If this is not the system default value, 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 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." |
|
CM-6(d)
CM-7
SC-5
|
|
Deactivate Wireless Network Interfaces |
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 wifi off
|
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. |
|
AC-17(8)
AC-18(a)
AC-18(d)
AC-18(3)
CM-7
|