Adware pushers have found a new way to trick you into downloading their annoying products: fake MP3 files. On Tuesday, security vendor McAfee Inc. reported that it has seen a huge spike in fake MP3 files spreading on peer-to-peer networks. Although the files have names that make them look like audio recordings, they're really Trojan horse programs that try to install a shoddy media player and adware on your computer, said Craig Schmugar, a researcher at McAfee.

"Detection of a trojan named Downloader-UA.h was added to the McAfee DAT files several days ago. Since that time more than 360,000 McAfee VirusScan Online users have reported detections, a whopping 32% of those reporting in the past 24 hours alone. Now Downloader-UA.h is not your everyday trojan, this detection covers fake music and video files associated with fastmp3player.com.",said Craig Schmugar.

"Once you run it, there is no content. You're taken to this site to install this player which you don't really need," he said.

Fake file names include: preview-t-3545425-changing times earth wind .mp3 and t-3545425-just got lucky.mp3. Schmugar listed more filenames, as well as details on the adware, in his blog post.

While the Mirar software tells users that it doesn't display popups, NetNucleus does deliver popup ads, so users who do not realize that they are installing two programs might feel tricked, Schmugar said. "You have a Window telling you that there are no popups and right behind it is a popup."

Although McAfee has seen some nasty software disguising itself as media files in the past, it has never seen anything on this scale, Schmugar said.