Anti-virus outfit McAfee says that it is tracking the worst malware outbreak in three years.

McAfee Avert Labs said that there have been more than 500,000 detections of a Trojan horse masquerading as a media file found on computers since Friday on services like Limewire and eDonkey. The malware is linked into an adult video, the Lion King in Portuguese, or the Girls Aloud theme from the St Trinnians soundtrack.

Craig Schmugar, threat researcher at McAfee Avert Labs, said that the user is left with a fake MP3 file taking up space, a worthless MP3 player, adware that claims not only to not display popups, but also to block them, and more adware that successfully displays popup and popunder ads.