Models for Threat Assessment in Networks

Computer Science Central to computer security are detecting attacks against systems and managing computer systems to mitigate threats to the system. Attacks exploit vulnerabilities in the system such as a programming flaw. Threats are vulnerabilities which could lead to an attack under certain circumstances. The key to the detection of attacks is discovering an ongoing attack against the system. Mitigating threats involves a continuous assessment of the vulnerabilities in the system and of the risk these vulnerabilities pose with respects to a security policy. Intrusion detection systems (IDS) are programs which detect attacks. The goal is to issue alerts only when an actual attack occurs, but also to not miss any attacks. The biological immune system provides a compelling model on which to base an IDS. This work adds the biological concepts of positive selection and collaboration to artificial immune systems to achieve a better attack detection rate without unduly raising the false alarm rate. Attack graphs assess the threat to the system by showing the composition of vulnerabilities in the system. The key issues with attack graphs are scalability to larg