UBTU-16-010210 - Passwords for new users must have a 24 hours/1 day minimum password lifetime restriction.
Enforcing a minimum password lifetime helps to prevent repeated password changes to defeat the password reuse or history enforcement requirement. If users are allowed to immediately and continually change their password, then the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse.
Configure the Ubuntu operating system to enforce a 24 hours/1 day minimum password lifetime. Add, or modify the following line in the '/etc/login.defs' file: PASS_MIN_DAYS 1