Botnet is a jargon term for a collection of software robots, or bots, that run autonomously and automatically. The term is often associated with malicious software but it can also refer to the network of computers using distributed computing software. It a harmful malware that is difficult to rout.
The Srizbi botnet, also known by its aliases of Cbeplay and Exchanger, is the world’s largest or second-largest botnet depending on expert reports, and is responsible for sending out more than half of all the spam being sent by all the major botnets combined.The botnets consist of computers infected by the Srizbi trojan, which sends spam on command. The botnet suffered a significant setback in November 2008 when hosting provider McColo was taken down; global spam volumes reduced by up to 75% as a result of this action.
Srizbi was also ranked as the largest spamming botnet last month by researchers at SecureWorks, but for the most part it has been overshadowed by the better-known Storm and Kraken and/or Bobax botnets. Srizbi now sends more spam than all other botnets combined.
Srizbi was thought to have been down for fews when its hosting company McColo was pull down and it was a time when spam levels dropped down sensibly. Unfortunately, the child computers used an internal algorithm to generate new domains to connect to and the spammers survived .