Total Posts: 889
Sorry to hear about your problem - but that sounds very strange, I have to say. The ONLY files/directories that have to be CHMOD-ed to 777 are:
[dir] magento/media (and subfolders)
Also make sure to use a custom admin path and password-protect the downloader directory using .htaccess.
Did you host tell you exactly how/where the security on Magento was compromised?