Even though the Netsky-P worm first hit the wild more than two years ago, it has made the list of Top Threats yet again.

The worm first appeared in March of 2004. And it's back again. Netsky-P is the third most widely spread malware circulating on the Internet today, according to analysts at Central Command, an anti-virus and anti-spam company based in Medina, Ohio.

This past month, Netsky-P accounted for 1.88 percent of all malware moving around the globe.

The Netsky family of worms in general is having a resurgence, despite the fact that new variants aren't hitting the Wild these days. This month, four of the top five threats are variants in that family, according to Central Command. And like Netsky-P, its sibling Netsky-Q, which sits in the second spot this month, first hit the Wild more than two years ago.

''It originally was out there in a big way so it's still just hanging on,'' says Steve Sundermeier, a vice president at Central Command. ''It's just a worm that has real longevity. People aren't installing anti-virus software. They're not updating for it. The Netsky family just doesn't seem to go away.''

The P variant spreads through email, as well as through network shares. Sundermeier points out that once the worm finds those shared files, it will drop a ''whole laundry list'' of added files into them.

Netsky-P also employs social engineering tricks. At one point, the worm's author even disguised the variant as a Harry Potter game.