There’s no doubt that domain accounts with weak passwords can be a serious concern for companies, there are a few ways you can protect yourself against issues like this. The first is to set a domain and local account lockout policy and the second is to enforce password complexity. However if your users are using “Password1” as their password, neither of these steps will protect you.
Why not copy and paste the following into your /etc/john.conf and try them out! Got a suggestion for a rule? Leave a comment! They can then be called with ‐‐rules=Try, ‐‐rules=TryHarder and ‐‐rules=BeBrutal! You can find an explanation of how these rules are built here.