#4 Cutwail:

Fact: Cutwail unleashed DDoS attacks against hundreds of websites across the globe

Founded in the year 2007, Cutwail is also called Pushdo and Pandex.

Cutwail rose to fame with its attacks directed against hundreds of websites back in the year 2010. The botnet unleashed a huge spree of DDoS attacks on hundreds of private and public websites, including websites of CIA, Twitter and FBI. The reasons for this attack weren't fully understood, and some experts described it as an "accident", mainly due to the lack of damage and disruption, along with the infrequency of the attacks

In the year 2009, Cutwail was considered to be as the largest botnet in terms of infected hosts. The same year security provider MessageLabs reported that the total size of the botnet was around 1.5 to 2 million individual computers, capable of sending 74 billion spam messages a day, or 51 million every minute.

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