Netsky is a prolific family of
computer worms which affect Microsoft Windows operating systems. The first variant appeared on Monday, February 16, 2004. The "B" variant was the first family member to find its way into mass distribution. It appeared on Wednesday, February 18, 2004. 18-year-old
Sven Jaschan of
Germany confessed to having written these, and other worms, such as
Sasser.