TOSS 5 must automatically lock an account when three unsuccessful login attempts occur during a 15-minute time period.

By limiting the number of failed login 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-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

Note: If the system administrator (SA) demonstrates the use of an approved centralized account management method that locks an account after three unsuccessful login attempts within a period of 15 minutes, this requirement is not applicable.

Verify TOSS 5 locks an account after three unsuccessful login attempts within a period of 15 minutes using the following command:

$ grep fail_interval /etc/security/faillock.conf 

fail_interval = 900

If the "fail_interval" option is not set to "900" or less (but not "0"), the line is commented out, or the line is missing, this is a finding.

Configure TOSS 5 to lock out the "root" account after a number of incorrect login attempts within 15 minutes.

Enable "pam_faillock.so" using the following command:

$ authselect enable-feature with-faillock 

Edit the "/etc/security/faillock.conf" file as follows:

fail_interval = 900