On July 16, 2001, vulnerabilities in the Windows Internet Information Services Server (IIS) made media headlines when the computer worms Code Red I and later Code Red II propagated within hours of each other and moved rapidly across the Internet, taking over every vulnerable computer on the Internet.

By definition, a worm is a virus-like program that spreads from one computer to another without human intervention. Code Red II was especially dangerous because it altered approximately 100,000 Windows NT and Windows 2000 Web servers on the Internet and PCs, permitting any unauthorized user to log onto them and exercise total control. As of August 10, 2001, Symantec Security Response created a tool to perform a vulnerability assessment of computers and to remove both Code Red I and II.

See Also: Malware; Vulnerabilities of Computers; Worm.