SRG-OS-000070-GPOS-00038
The operating system must enforce password complexity by requiring that at least one lowercase character be used.
Canonical Source
SV-203626r982196_rule ( from General Purpose Operating System Security Requirements Guide )Description
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.