A Method to Enhance SCADA Systems Survivability with Exogenous Monitors

A method is proposed for enhancing SCADA systems survivability using exogenous isomorphic real-time monitor and simulation monitor. The formal definition of monitors is given. The fundamental principles of attack resistance, malicious operation detection and fault prediction are introduced, which are accomplished by using cooperation between the real-time monitor and simulation monitor. The real-time monitor is responsible for monitoring the states of SCADA systems, events and control commands, estimating whether there is faults and risk in systems based on states and implementation commands of system, and creating a simulation monitor if it is necessary. The simulation monitor is responsible for simulating implementation of control command, monitoring the process of simulation, forecasting the results of control commands, and estimating whether the commands are harmful based on the results. Finally, a water treatment system is given to illustrate the feasibility and effectiveness of the method.