Vulnerability Discussion

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.

Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.

Check

Verify that RHEL 9 enforces password complexity by requiring at least one lowercase character.

Check the value for "lcredit" with the following command:

$ sudo grep lcredit /etc/security/pwquality.conf /etc/security/pwquality.conf/*.conf

/etc/security/pwquality.conf:lcredit = -1

If the value of "lcredit" is a positive number or is commented out, this is a finding.

Fix

Configure RHEL 9 to enforce password complexity by requiring at least one lowercase character be used by setting the "lcredit" option.

Add the following line to "/etc/security/pwquality.conf" (or modify the line to have the required value):

lcredit = -1