Almost 500,000 users have been trapped by a booby-trapped media file, states security firm McAfee. This fake file poses as a tempting music track, movie or short video and has been profusely seeded on file-sharing networks to snare gullible people.

McAfee stated the fake media file outbreak was one of the largest it had come across for about three years. Those who run the fake file get bombarded with unnecessary pop-up ads and also risk compromising the safety of their computer.

The fake file (Trojan) has been distributed on the eDonkey and Limewire file-sharing networks. It has many names and is written in various different languages so as to trick people for downloading it. The titles make it appear to be a music track or a full version of any popular movie.

Anyone downloading it and then trying to run it - is asked to install a ‘codec’, which will play the compatible media. Instead of doing so, a bundle of adware, which plagues a user with pop-ups, gets installed. McAfee stated witnessing such a large outbreak was very rare.