Scientists may have found a new way to combat the most dangerous form of computer virus. The method automatically detects within minutes when an Internet worm has infected a computer network. Network administrators can then isolate infected machines and hold them in quarantine for repairs. Ness Shroff, Ohio Eminent Scholar in Networking and Communications at Ohio State University, and his colleagues describe their strategy in the current issue of IEEE Transactions on Dependable and Secure Computing. They discovered how to contain the most virulent kind of worm: the kind that scans the Internet randomly, looking for vulnerable hosts to infect. "These worms spread very quickly," Shroff said. "They flood the Net with junk traffic, and at their most benign, they overload computer networks and shut them down." Code Red was a random scanning worm, and it caused .6 billion in lost productivity to businesses worldwide in 2001.