Information
By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account.
Satisfies: SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005
Solution
Configure the operating system to lock an account for the maximum period when three unsuccessful logon attempts in 15 minutes are made.
Modify the first three lines of the auth section of the "/etc/pam.d/system-auth-ac" and "/etc/pam.d/password-auth-ac" files to match the following lines:
auth required pam_faillock.so preauth silent audit deny=3 even_deny_root fail_interval=900 unlock_time=604800
auth sufficient pam_unix.so try_first_pass
auth [default=die] pam_faillock.so authfail audit deny=3 even_deny_root fail_interval=900 unlock_time=604800
account required pam_faillock.so