Criminals have been able to gain control of millions of personal computer systems (PCs) for various nefarious activities, such as generating spam messages, propagating viruses and worms used to compromise additional computer systems, stealing personal information for identity theft, and launching denial of service (DOS) attacks on computer systems. Networks of compromised machines (also known as “zombies”) are referred to as botnets. A botnet may include hundreds, thousands, or even millions of zombie computer systems that are under the control of the botnet. For example, the “Storm” botnet has been estimated to control as many as one to two million zombie computer systems to fewer than 160,000 zombie computer systems. Another botnet, the “bobax” or “Kraken” network has been estimated to control between 160,000 and 400,000 zombie computer systems, and the “Srizbi” network has been estimated to control 315,000 zombie computer systems.
Cybercriminals in control of botnets often offer the services of the botnets to the highest bidder. Often the botnet may be used to launch attacks, such as denial of server (DOS) attacks, on the computer systems of government and/or private entities. Terrorist groups may also harness botnets to stage attacks against government information systems and/or other critical infrastructure, such as power plants, air traffic control computer systems, and particularly well-funded terrorist organizations may have the resources to capture their own network of zombie computer systems for use in staging attacks. The size of a botnet can be quite extensive. Cyber terrorist groups may have as many as millions of zombie computer systems under their control, providing the terrorist groups with significantly more computing resources at their disposal for staging attacks the government and/or private entities currently often have at their disposal for thwarting such attacks.