Internet Worms

Worms - Types and Habitats

Penetration of a remote system can be accomplished in any of three ways... In each case the worm arranges to get a remote command interpreter which it can use to copy over, compile and execute the 99-line bootstrap. The bootstrap sets up its own network connection with the local worm and copies over the other files it needs, and using these pieces a remote worm is built and the infection procedure starts over again. - Donn Seeley; A Tour of the Worm; University of Utah.

Internet worms are truly autonomous virtual viruses, spreading across the net, breaking into computers, and replicating without human assistance and usually without human knowledge.
Worms are particularly interesting technological constructs, with an intriguing mathematical structure and complexity. They fascinate because they take the digital imitation of life to another step -- they autonomously search for computers, penetrate them, and replicate their intelligence to continue the process.
An Internet worm can be contained in any kind of virus, program orscript. Sometimes their inventor will release them into the wild in a single copy, leaving them to replicate by themselves through a variety of stratagems and protocols.
History. Worms use a variety of methods to propagate across the Internet. Early worms simply scanned the local network drives and folders and inserted themselves into programs wherever they could, trusting human beings to move disks and directories around in the normal course of things so they could continue to spread.