Vulnerability 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.

In OL 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.

From "faillock.conf" 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

Check

Note: This check applies to OL versions 8.2 or newer. If the system is OL version 8.0 or 8.1, this check is not applicable.

Verify the "/etc/security/faillock.conf" file is configured to lock an account after three unsuccessful logon attempts:

$ sudo grep 'deny =' /etc/security/faillock.conf

deny = 3

If the "deny" option is not set to "3" or less (but not "0") or is missing or commented out, this is a finding.

Fix

Configure OL 8 to lock an account when three unsuccessful logon attempts occur.

Add/modify the "/etc/security/faillock.conf" file to match the following line:

deny = 3