The system must require administrator action to unlock an account locked by excessive failed login attempts.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-50637	OL6-00-000356	SV-64843r1_rule		Medium

Description
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.

STIG	Date
Oracle Linux 6 Security Technical Implementation Guide	2014-06-12

Details

Check Text ( C-53143r1_chk )
To ensure the failed password attempt policy is configured correctly, run the following command: # grep pam_faillock /etc/pam.d/system-auth-ac The output should show "unlock_time="; the largest acceptable value is 604800 seconds (one week). If that is not the case, this is a finding.

Fix Text (F-55435r1_fix)
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": Add the following lines immediately below the "pam_unix.so" statement in the AUTH section of "/etc/pam.d/system-auth-ac": auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900 auth required pam_faillock.so authsucc deny=3 unlock_time=604800 fail_interval=900 Note that any updates made to "/etc/pam.d/system-auth-ac" will be overwritten by the "authconfig" program. The "authconfig" program should not be used.

Fix Text (F-55435r1_fix)

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":

Add the following lines immediately below the "pam_unix.so" statement in the AUTH section of
"/etc/pam.d/system-auth-ac":

auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900

auth required pam_faillock.so authsucc deny=3 unlock_time=604800 fail_interval=900

Note that any updates made to "/etc/pam.d/system-auth-ac" will be overwritten by the "authconfig" program. The "authconfig" program should not be used.