The worm, dubbed Nopir.B, spreads over peer-to-peer networks and appears to have originated in France, security researchers at Sophos said Friday.
Nopir.B is designed to look like a DVD-cracking program, to fool people looking for a program that will circumvent copy-restriction technology on the discs. When the worm is downloaded and run, it attempts to delete all MP3 music files and wipe some programs from the infected PC, the company said in its advisory.
Sophos said it believes the author of the virus may be looking to stamp out music piracy.
"The Nopir.B worm targets people it believes may be involved in piracy, but fails to discriminate between the true criminals and those who may have legally obtained MP3 files," Graham Cluley, senior technology consultant for Sophos, said in a statement. "Whichever side of the fence you come down on in regards to Internet piracy, there's no debate about the criminal nature of this worm--it's designed to inflict malicious damage on people's Windows computers."
Sophos has received few reports of the virus, but recommended that people update their security software. The malicious software affects PCs running Microsoft Windows.
Dan Ilett of ZDNet UK reported from London.