Level 1 - Server Level 1 - Workstation
An account with an empty password field means that anybody may log in as that user without providing a password.
All accounts must have passwords or be locked to prevent the account from being used by an unauthorized user.
Run the following command and verify that no output is returned:
# cat /etc/shadow | awk -F: '($2 == "" ) { print $1 " does not have a password "}'
If any accounts in the /etc/shadow file do not have a password, run the following command to lock the account until it can be determined why it does not have a password:
# passwd -l <username>
Also, check to see if the account is logged in and investigate what it is being used for to determine if it needs to be forced off.