RHEL 9 must require the change of at least four character classes when passwords are changed.

STIG ID: RHEL-09-611130  |  SRG: SRG-OS-000072-GPOS-00040 | Severity: medium |  CCI: CCI-004066

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 a password, the greater the number of possible combinations that need to be tested before the password is compromised.

Check

Verify the value of the "minclass" option in "/etc/security/pwquality.conf" with the following command:

$ grep minclass /etc/security/pwquality.conf

minclass = 4

If the value of "minclass" is set to less than "4", or is commented out, this is a finding.

Fix

Configure RHEL 9 to require the change of at least four character classes when passwords are changed by setting the "minclass" option.

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

minclass = 4