Title

RHEL 8 must include root when automatically locking an account until the locked account is released by an administrator when three unsuccessful logon attempts occur during a 15-minute time period. (Cat II impact)

Discussion

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. RHEL 8 can utilize the "pam_faillock.so" for this purpose. Note that manual changes to the listed files may be overwritten by the "authselect" program. From "Pam_Faillock" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. In RHEL 8.2 the "/etc/security/faillock.conf" file was incorporated to centralize the configuration of the pam_faillock.so module. Also introduced is a "local_users_only" option that will only track failed user authentication attempts for local users in /etc/passwd and ignore centralized (AD, IdM, LDAP, etc.) users to allow the centralized platform to solely manage user lockout. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Check Content

Check that the system includes the root account when locking an account after three unsuccessful logon attempts within a period of 15 minutes with the following commands: If the system is RHEL version 8.2 or newer, this check is not applicable. Note: If the System Administrator demonstrates the use of an approved centralized account management method that locks an account after three unsuccessful logon attempts within a period of 15 minutes, this requirement is not applicable. $ sudo grep pam_faillock.so /etc/pam.d/password-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "even_deny_root" option is missing from the "preauth" line with the "pam_faillock.so" module, this is a finding. $ sudo grep pam_faillock.so /etc/pam.d/system-auth auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so If the "even_deny_root" option is missing from the "preauth" line with the "pam_faillock.so" module, this is a finding.

Fix Text

Configure the operating system to include root when locking an account after three unsuccessful logon attempts occur in 15 minutes. Add/Modify the appropriate sections of the "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" files to match the following lines: auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0 auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0 account required pam_faillock.so The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command: $ sudo systemctl restart sssd.service

Additional Identifiers

Rule ID: SV-230344r646874_rule

Vulnerability ID: V-230344

Group Title: SRG-OS-000021-GPOS-00005

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