Looking at that site, I can't see anywhere that they might be inserting code, so as has been said before, the main server must have been hacked/root access gained. I would suggest moving you sites away from there asap, then taking legal proceedings against your current hosts for breach of contract.
The site is using zencart and with any of the shelf carts you end up with one or more folder 0777. therefor file injection can occour. That would be a client side site hack.
on the main index page
"<u style="display:none;"><a href="http://veteransadv..."
Cropped the url for security reasons but on one of the reoccurring site links I had a look at had a url pointing to
lang/deutsch/tfslc/
and
lang/deutsch/akhfm/
Again typically lang would be set to 0777. thus allowing spammers to add and choose what files to add. Some of the links in one of the pages go to an usa college/uni. The spider web continues.
The two issues i have at the moment is this.
Either the public_html folder was left at 0777 or the index.php was 0777.. So potentially if this was a single case - password compromised or a mishap by the webdesign company.
But based on what Trevor has said that his and other sites have had the same thing done it means the server is compromised either by root access or some malicious files in /tmp
Update:
The index.php has around 300 links to other sites that then link to other sites to keep up the spiderweb of keeping spam links open......
Edited by Taras (Wed 04-Nov-09 22:11:56)