Information
The operating system must enforce password complexity by requiring that at least one numeric character be used.
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.
RHEL 8 operating systems utilize "pwquality" as a mechanism to enforce password complexity. Note that in order to require numeric characters, without degrading the minlen value, the credit value must be expressed as a negative number in "/etc/security/pwquality.conf".
Solution
Configure the operating system to enforce password complexity by requiring that at least one numeric character be used by setting the "dcredit" option.
Add the following line to /etc/security/pwquality.conf (or modify the line to have the required value):
dcredit = -1