Thousands of web sites have mystery malware exploit

Interesting item covered by The Register about a huge number of web sites apparently serving up malware. And as yet no one has worked out how they were compromised.

This is a really sneaky exploit - when a user requests the home page from the site, a reference to a local javascript file is included dynamically in the page. The name of the file changes randomly and the file only exists while the user is accessing the page. So it doesn't persist and can't be spotted by admins. The javascript contains multiple exploits to attempt to install a backdoor to your system.

No one has yet worked out how these servers were compromised in the first place. Most of them are running Apache on Unix/Linux - so what sets these apart from the many tens of thousands of hosting servers running the same stuff?

Earlier in the week the estimate was around 10,000 infected sites.

You can read the full story at Scansafe and The Register.

Be careful out there.