WindowSecurity.com - Robot Wars – How Botnets Work

Title: Robot Wars – How Botnets Work
Author: hakin9
Summary: One of the most common and efficient DDoS attack methods is based on using hundreds of zombie hosts. Zombies are usually controlled and managed via IRC networks, using so-called botnets. Let's take a look at the ways an attacker can use to infect and take control of a target computer, and let's see how we can apply effective countermeasures in order to defend our machines against this threat.
Link: http://www.WindowSecurity.com/articles/Robot-Wars-How-Botnets-Work.html