Netsky-P rose from seventh place last month to first place this month on at least one list of the worst malware.

The variant of the highly damaging Netsky family, the virus ranks high on several anti-virus vendor charts. Sophos, Inc., an anti-virus and anti-spam vendor based in Lynnfield, Mass., ranks Netsky-P as the most dangerous virus threat this month. It accounts for 23.2 percent of all the bugs roaming the Internet.

Netsky-P was first detected on March 22, 2004. It's a mass-mailing worm which spreads by emailing itself to addresses harvested from files on local drives. The worm copies itself to the Windows folder as FVProtect.exe.