[akrasia]

I'm not an expert in the field but from what I know, SHA1 is a one way function. When an encrypted password is cracked, YES, the hackers know that specific password. They brute forced it by guessing the password, running it through SHA1, and comparing the output to the hash. If they are the same, then they guessed the right password.

They do not know any other passwords and if "salt" was used, they would have to brute force each password. I think salt wasn't used in this case so once they crack someone's password, they know every other user who used the same password. So if you and I used the same password, and they brute forced yours already, they will know that I have the same password.