Information
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.
Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128
Solution
Configure the operating system to lock an account when three unsuccessful logon attempts occur.
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