Not all SCADA is Equal: Impact of Control Models on ICS Threat Landscape

There are almost as many ways to implement Industrial Control Systems as there are ways to control industrial systems. This produces a wide-varying range of possible architectures for the SCADA networks that control them. This paper organizes SCADA networks based on these various control architectures in order to evaluate how different controlmodels and architectures can affect the threat model.We observe that distributed control, with control logic in the endpoints, is more susceptible to attacks on SCADA endpoints and that distributed state architectures,with centralized control, ismore susceptible to attacks on the SCADA master.