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-64843r3_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	2020-05-15

Details

Check Text ( C-53143r3_chk )
To ensure the failed password attempt policy is configured correctly, run the following command: # grep pam_faillock /etc/pam.d/system-auth /etc/pam.d/password-auth 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-55435r3_fix)
To configure the system to lock out accounts after a number of incorrect logon attempts and require an administrator to unlock the account using "pam_faillock.so", modify the content of both "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" as follows: Add the following line immediately before the "pam_unix.so" statement in the "AUTH" section: auth required pam_faillock.so preauth silent deny=3 unlock_time=604800 fail_interval=900 Add the following line immediately after the "pam_unix.so" statement in the "AUTH" section: auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900 Add the following line immediately before the "pam_unix.so" statement in the "ACCOUNT" section: account required pam_faillock.so Note that any updates made to "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" may be overwritten by the "authconfig" program. The "authconfig" program should not be used.

Fix Text (F-55435r3_fix)

To configure the system to lock out accounts after a number of incorrect logon attempts and require an administrator to unlock the account using "pam_faillock.so", modify the content of both "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" as follows:

Add the following line immediately before the "pam_unix.so" statement in the "AUTH" section:

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

Add the following line immediately after the "pam_unix.so" statement in the "AUTH" section:

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

Add the following line immediately before the "pam_unix.so" statement in the "ACCOUNT" section:

account required pam_faillock.so

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