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