My forum hacked - any help appreciated

[knucklenitz]

Hi -

My forum was hacked sometime between last night and 9am this morning. An image is displayed when going to the main page or to the admin panel. The image says it's been hacked and gives the hackers email address. The source shows two websites, one for the image and another that I'm not sure what it means but it says embed src="website address here". I'm not exactly sure but the source doesn't appear to show any clue to what the hack is.

I have checked my index.php and even uploaded new. I have my admin and mod cp renamed and have my install and include directories password protected with htaccess. I have gone through all of my files and don't see any with new dates. My config file doesn't have anything new added from what I can tell. Only my name is set as unchangeable admin. This all leads me to believe it's a database issue. I do have a backup of the database from yesterday 5pm and this morning at 5am, although I think the 5am is compromised.

From what I have for security, how could someone get in? Also, what is the best step to repair...and make it even more secure.

Thanks, slightly panicking since this is used for our customers.