Originally Posted by Thanks to Migmaf, you could be serving porn (unintentionally, that is)

Hacking computers for spamming is nothing new, but the stakes are getting a little higher as a new scheme uses unsuspecting hosts to serve up porn. Essentially what we have are porn spammers who are hacking machines via a trojan app to host the actual porn for use in attracting new clients. They then earn money from referral fees. It's also said that this same scheme is being used to perpetuate PayPal scams. With a network of hacked machines, the criminals in question can rotate through the machines to make detection much more difficult, while spreading out the bandwidth hit to a level that's probably difficult to detect. Still, there's a flaw in the ring.

The current version of the ring is not completely anonymous, since the hijacked machines download the pornographic ads from a single Web server. According to the computer investigators, that machine apparently is owned by Everyones Internet, a large independent Internet service company in Houston that also offers Web hosting services to a large number of companies. Jeff Lowenberg, the company's vice president of operations, said that he was not aware of any illegal activity on one of his company's computers but said that he would investigate.

You can find more technical details, including ways to check for infection, here. As of yet, it has not been determined just how the trojan gets onto a machine. So far, it appears to only affect Windows users.