Anomaly-based self protection against network attacks

The Internet has grown exponentially over the last few years and has expanded commensurately in both scope and variety. In addition to the increasing number and dependence upon Internet resources and services, there are also increasing interconnectedness and interdependence among large and complex systems; a failure in one sector can easily affect other sectors. Disruption of critical Internet services can be very expensive to businesses, life threatening for emergency services, and ultimately threaten the defense and economic security nationwide. In fact, the commission on critical infrastructure reports that the potential for disaster in the U.S. as a result of network attacks is catastrophic [53]. This raises an important question given the fragility of Internet infrastructures to small random failures (such as hardware failures, bad software design, innocenthumanerrors, and environmental events). According to a recent study, the Internet is robust to random failures, however the Internet’s reliance on a few key nodes makes it vulnerable to an organized attack and it has been shown that the average performance of the Internet would be reduced by a factor of two if only 1% of the most connected nodes are disabled. If 4% of them were shut down the network would become fragmented and unusable [41].