Srizbi Botnet

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.