In what's being called the largest fake media file outbreak in three years, <A HREF="http://tech.yahoo.com/blogs/null/92638/fake-infected-media-file-attacks-half-a-million-victims-in-a-week/">some 500,000 people have fallen prey</A> to a phony music or video track that is actually a spyware-infested Trojan horse. Usually purporting to be a music track with an MP3 file extension (in this case, an MP3 track from the UK group Girls Aloud), the file is actually an installer that claims to require a special codec and a special media player to play back the file.

Install the codec and what you really get is a computer screen full of pop-ups delivered through a variety of malware programs. You can see what the infection process looks like by checking out the video on this post. The attack is being distributed primarily through peer-to-peer networks. This is hardly an original attack, but the scale is immense: Those 500,000 attacks occurred in the space of just one week.