Mega-D: March, 2010
The takedown of Mega-D, also known as Ozdok, was spearheaded by researchers at anti-botnet firm FireEye. The botnet, a byproduct of PC infections linked to the Mega-D Trojan, comprised tens of thousands of machines and was responsible for sending out a large portion of the spam on the Internet–at some points north of 30 percent. By March, 2010, researchers had identified the botnet and had a good handle on its command-and-control structure. Researchers at FireEye then worked with Internet Service Providers (ISPs) to take the servers offline.