Next-Generation Misuse and Anomaly Prevention System

Network Intrusion Detection Systems (NIDS) aim at preventing network attacks and unauthorised remote use of computers. More accurately, depending on the kind of attack it targets, an NIDS can be oriented to detect misuses (by defining all possible attacks) or anomalies (by modelling legitimate behaviour and detecting those that do not fit on that model). Still, since their problem knowledge is restricted to possible attacks, misuse detection fails to notice anomalies and vice versa. Against this, we present here ESIDE-Depian, the first unified misuse and anomaly prevention system based on Bayesian Networks to analyse completely network packets, and the strategy to create a consistent knowledge model that integrates misuse and anomaly-based knowledge. The training process of the Bayesian network may become intractable very fast in some extreme situations; we present also a method to cope with this problem. Finally, we evaluate ESIDE-Depian against well-known and new attacks showing how it outperforms a well-established indus-