Modeling and evaluating the survivability of an intrusion tolerant database system

∗Signatures are on file in the Graduate School. iii The immaturity of current intrusion detection techniques limits the traditional security systems in surviving malicious attacks. Intrusion tolerance approaches have emerged to overcome these vulnerabilities. Before intrusion tolerance is accepted as an approach to security, there must be quantitative techniques to measure its survivability. However, there are very few attempts to do quantitative, model-based evaluation of the survivability of intrusion tolerant systems, especially in database field. In this thesis, I focus on modeling the survivability of an intrusion tolerant database system in the presence of attacks. Before studying the survivability of intrusion tolerant systems, we need to have a better understanding of the attack behavior and its degree of spreading. Based on the classical epidemic model, a stochastic database damage propagation model is proposed. This model leads to a better understanding and prediction of the scale and speed o