A new worm is spreading through the KaZaA file-sharing service. Masquerading as a media file, W32.Benjamin targets online music swappers. "Tech Live" reports tonight.

Benjamin infects computers by converting them into KaZaA servers. The damage is minimal: The virus alters the registry settings slightly and dumps a folder called sys32 in the Windows temp file. That folder contains hundreds of phony media files that harbor the virus. Other unsuspecting KaZaA users who download files from an infected computer start the infection process all over again. This exponential growth has security experts concerned.

The worm also redirects victims' computers to an ad server intended to make money for the virus writers. The banner server was pulled as soon as its owners realized the influx in traffic was virus-related.

So far Benjamin is working only on the KaZaA network and infection rates are relatively low. Newsbytes.com reached Paul Komoszki, one of the writers of the virus. Komoszki told the site that the worm is only targeting those who try to download copyright material.

AC/DC and Metallica titles predominate in the fake file names, but child porn titles are also scattered in. Komoszki says he and the other virus writers believe that this type of virus may one day fight online child porn.

A free removal tool is available from security firm BitDefender.