In 1997, the U.S. Department of Defense conducted a fake cyber attack to assess the capability of its information systems to respond to such an attack and still protect the national information infrastructure. The simulation, called Eligible Receiver, revealed dangerous vulnerabilities in the military information systems.
A subsequent mock cyber attack against the Department of Defense information systems, called Eligible Receiver 2003, similarly revealed a need for better coordination between military and nonmilitary agencies to be able to deploy a quick computer response attack as well as an effective preemptive attack.
Also, in July 2002, the U.S. Naval War College sponsored a multiple-day war game called “Digital Pearl Harbor.” The purpose of the game was to develop a scenario for a coordinated, multiple-industry, cyberterrorism attack against critical infrastructure systems. Though the test team concluded that there was a small possibility of a Digital Pearl Harbor occurring in the United States at the time of the study, a survey of the cyber war game participants afterward indicated that almost 80% of them believed that a strategic cyber attack could occur in the near future.
As a result of these simulated cyber attacks against critical infrastructures, many of the participating experts believed that the telecommunication systems had adequate redundancy in their design to be able to prevent widespread downtime. However, the Internet and the computer systems supporting the financial infrastructure, they said, appeared to be vulnerable to attack.
Wilson, C. CRS Report for Congress: Computer Attack and Cyberterrorism: Vulnerabilities and Policy Issues for Congress. [Online, October 17, 2003.] CRS Report Website. http://www.fas.org/irp/crs/RL32114.pdf.