Release the hack but with a crypted password.
Crypt the password in base64, atom 128, megan-35 or anything else that's reversible.
Post the method and the order you crypt it like "base64>atom>megan>japoo" and tell them to use

or other website to reverse the crypt.
This will prevent leechers and n00bs to find the password for the hack.
For an example i've got this: " fdOkeg=Led=kR+m1Rub5 " and I crypted it using this method "ATOM-128>Base64>Megan35c" reversing it I get from " fdOkeg=Led=kR+m1Rub5 " the real data which is " 123456 " .