Vulnerability Discussion
If an account has an empty password, anyone could log on and run commands with the privileges of that account. Accounts with empty passwords must never be used in operational environments.
Check
Verify all accounts on the system to have a password by using the following command:
$ sudo awk -F: '!$2 {print $1}' /etc/shadow
If the command returns any results, this is a finding.
Fix
Configure all accounts on the system to have a password or lock the account by using the following commands:
Set the account password:
$ sudo passwd
Or lock the account:
$ sudo passwd -l