A computer program used in Distributed Denial of Service (DDos) attacks. A cracker plants software programs (or scripts) on large computers (known as servers) having high-speed connections to the Internet. These “planted” machines are controlled by the cracker through zombie processes.
Zombies lie in wait until the cracker sends them some signal telling them to bombard a targeted site. When the command is received, the zombies send thousands or more fake requests for information to the server—all at the same time. In an attempt to handle so many information requests, the targeted computer soon runs out of memory and other critical resources, causing it to slow down greatly or to come to a halt.
Schell, B.H. and Martin, C. Contemporary World Issues Series: Cybercrime: A Reference Handbook. Santa Barbara, CA: ABC-CLIO, 2004.