Botnet
A network of zombie computers
A botnet is a network of compromised systems infected with bots or backdoors, which can be controlled centrally by a botherder.
These networks are built up by campaigns of spammed-out trojans or worms and are used for malicious purposes, usually for financial gain. As well as expanding the botnet by sending out malicious code to infect new victims, the botnet can be used to send spam, host or visit websites, and even join forces in massive DDoS attacks, all of which can be profitable for the botherder.
