Botnets operate by infecting machines with malware that allows remote control. This document analyzes botnet detection methods and case studies. It describes how bots are installed through exploits and spread across compromised websites. Bots communicate back through protocols like IRC and HTTP to command and control servers, and this network traffic can be analyzed to identify infections and botnets. The document examines real botnet examples detected through their infection vectors, domain generation algorithms, and post-infection activity patterns.