Research / Projects

Distributed Denial of Service Attacks (DDoS)

Denial of Service attacks have been with us as long as the Web has been in existence. A DDoS attack is a series of coordinated accesses to a Web location designed to overwhelm the capability of the Web server to respond.

Such attacks can only achieve their purpose if a large number are sent nearly simultaneously to a target site, either by a large number of distinct individuals sending such commands, or by a small number of attackers spawning automated attacks by gaining access to remote computers (then called &lquot;zombie computers&rquot;) that then dispatch the attack.

DDoS gained greater notoriety at the time of the publicity regarding WikiLeaks and its release of US classified documents in November of 2010 ( In retaliation for some commercial entities refusing to accept any further donations to WikiLeaks, successful DDoS attacks were launched, presumably by supporters of WikiLeaks that crashed the Websites of PayPal and MasterCard. Later, counterattacks were launched against WikiLeaks (, thus creating what some have called the first "cyberwar".

A recent report published by Arbor Networks, the World Infrastructure Security Report 2010 (, has indicted that DDoS attacks currently are growing exponentially in number and severity. The unit used for measuring attacks is the level information requested in a unit of time, usually Gigabits per second or Gbps. Since the WISR was first published six years ago, the greatest severity of DDoS attack reported has grown from 10 Gbps to 100 Gbps, with a doubling from 50 Gbps to 100 Gbps in the last year.

Research is ongoing at in the Howard Cybersecurity Education and Research Center to investigate defenses against such DDoS attacks. Dr. Patterson recently gave a guest lecture to the Computer Science and Cybersecurity faculty and students at the University of Tennessee Chattanooga on this topic, and was interviewed at length on National Public Radio on this topic. The audio interview is available online at