The system must disable accounts after excessive login failures within a 15-minute interval.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-50635	OL6-00-000357	SV-64841r3_rule		Medium

Description
Locking out user accounts after a number of incorrect attempts within a specific period of time prevents direct password guessing attacks.

STIG	Date
Oracle Linux 6 Security Technical Implementation Guide	2018-09-19

Details

Check Text ( C-53141r2_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 For each file, the output should show "fail_interval=" where "interval-in-seconds" is 900 (15 minutes) or greater. If the "fail_interval" parameter is not set, the default setting of 900 seconds is acceptable. If that is not the case, this is a finding.

Check Text ( C-53141r2_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

For each file, the output should show "fail_interval=" where "interval-in-seconds" is 900 (15 minutes) or greater. If the "fail_interval" parameter is not set, the default setting of 900 seconds is acceptable. If that is not the case, this is a finding.

Fix Text (F-55431r3_fix)
Utilizing "pam_faillock.so", the "fail_interval" directive configures the system to lock out accounts after a number of incorrect logon attempts. 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-55431r3_fix)

Utilizing "pam_faillock.so", the "fail_interval" directive configures the system to lock out accounts after a number of incorrect logon attempts. 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.