Well to start with, check my image and go to the sucuri.net site and check the links effected and then search those pages for the hidden iframes and remove them. That isn’t the end of it you have to find and close the vulnerability or you could well be hacked again. I can’t help you with that, it isn’t an area I’m that familiar with.

Hacked Sites - This is commonly down to old content management software being vulnerable, PHP, Joomla, Wordpress, SQL, etc. etc. So ensure that whoever is responsible for for that has the latest versions.

Also see, Tips for Cleaning & Securing Your Website, http://www.stopbadware.org/home/security.

Also see, Help: I Got Hacked. Now What Do I Do? http://technet.microsoft.com/de-de/library/cc512587(en-us).aspx.

This type of thing is also often found in any template files so anything created off them would have the code inserted.