Presentation from PHDays 2012 conference on botnet detection. highlevel but fun.
A botnet is a collection of compromised computers, each of which is known as a 'bot', connected to the Internet. When a computer is compromised by an attacker, there is often code within the malware that commands it to become part of a botnet. The "botmaster" or "bot herder" controls these compromised computers via standards-based network protocols such as IRC and http