2009 saw many, many new botnet outbreaks and advancements in their criminal management. Damballa tracked thousands of distinct criminal operated botnets and identified millions of newly compromised enterprise systems each day. Tomorrow I ll be covering the Top-10 most successful malware families used by botnetnet operators in 2009. ClickFraudBotnet operated by a criminal team that focused on sophisticated click-fraud attacks and conducted their activities within enterprise networks. Conficker.A was the most successful variant of 2009.
Source: https://threatpost.com/behind-scenes-botnet-epidemic-021710/73549/