Penetration Testing and Network Defense

Chapter 15. Denial-of-Service Attacks

Internet security isn’t lousy; there just isn’t any.

—Padgett Peterson, Lockheed Martin

If you have ever had a system crash on you, you know how frustrating it is when you lose your data and are unable to work. This is the goal of a denial-of-service (DoS) attack. A DoS attack is one in which a malicious hacker renders a system unusable. He can do this through overloading a system so that it crashes, resulting in no one being able to access it, or by sending traffic with exceptional conditions in a way that the system was never prepared to handle. Malicious hackers cause DoS attacks when they are unable to access data otherwise or simply want the notoriety.

DoS attacks are categorized into one of three types: ...