WordPress Site Hacked

Our WordPress (3.0.1) website was hacked 2 days ago. The defacer went to theme-editor.php and edited our index.php. The defacer was able to log in without any traces of bruteforcing. I think he was knowledgeable of the password at first. Though before the access, he went to view wp-content’s contents and plugins before he was able to log in. The codes and the database were unchanged. The password for wp-admin was touched though.

The hacker named protocol is from Dos-DZ team who’s a part of a network of hackers named DZ hackers.

So what do you guys think?