Nimda is another computer worm that first came on the scene in 2001. Nimda is a virus-worm type of worm. The Nimda worm aims to infect any machine running the Windows operating system and wreak havoc, especially on Windows IIS servers, by jamming the network.
Nimda’s spread method is difficult to pin down since the worm can not only spread through websites containing malicious code but also through malicious email messages. In some ways, Nimda can be classified as a multi-vector worm.