Using Model-based Intrusion Detection for SCADA Networks∗

In a model-based intrusion detection approach for protecting SCADA networks, we construct models that characterize the expected/acceptable behavior of the system, and detect attacks that cause violations of these models. Process control networks tend to have static topologies, regular traffic patterns, and a limited number of applications and protocols running on them. Thus, we believe that model-based monitoring, which has the potential for detecting unknown attacks, is more feasible for control networks than for general enterprise networks. To this end, we describe three model-based techniques that we have developed and a prototype implementation of them for monitoring Modbus TCP networks.