On September 18, 2001, the Nimda worm appeared, reportedly infecting hundreds of thousands of computers around the world. Nimda was a computer worm, and also a file infector. It quickly spread, eclipsing the economic damages caused by past outbreaks such as Code Red. Multiple propagation vectors allowed Nimda to become the Internet's most widespread virus/worm within 22 minutes. Nimda affected both user workstations (clients) running Windows 95, 98, Me, NT, 2000 or XP and servers running Windows NT and 2000.