Forum Forum hacked - mass password reset - security
 

My forum may be compromised, let's say I have to reset the passwords of 10 million users. Let's put this in perspective.
That's not something that an admin is going to do one user at a time, and of course, setting the password expiration to 1 day would also not work because I can't have only my daily users resetting their passwords, there will be weekly and monthly users as well, and of course, it's awfully irritating when your password needs to be reset every 24 hour period.

What's the elegant solution one should use in this scenario?