A presentation at this week’s LEET ’11, a USENIX workshop on large-scale exploit and emergent threats, delves into the inner workings of the underground economy. Researchers had access to records from the Cutwail spam engine dated as far back as June 2009. The amount of spam sent from July 30 to August 25, 2010, was only around 30.3 percent accepted by mail servers. The researchers had roughly one-half to two-thirds of the active C&C servers, so they estimate overall numbers are likely higher.”]
Source: https://www.csoonline.com/article/2127919/behind-the-curtain-of-a-botnet-business.html