Bot Command-and-Control Servers

In the last six months of 2007, 4,091 bot command-and-control servers were identified. This is an 11% decrease from the previous reporting period, when 4,622 bot command-and-control servers were identified. The decrease in the number of bot command-and-control servers detected reflects the growing trend in the methods botnet owners are using to communicate with their bot-infected computers.

Source: Symantec Internet Security Threat Report, Vol. XIII