Formalization and co-simulation of attacks on cyber-physical systems

This paper presents a methodology for the formal modeling of security attacks on cyber-physical systems, and the analysis of their effects on the system using logic theories. We consider attacks only on sensors and actuators. A simulated attack can be triggered internally by the simulation algorithm or interactively by the user, and the effect of the attack is a set of assignments to the variables defined in the Controller. The global effects of the attacks are studied by injecting attacks in the system model and co-simulating the overall system, including the system dynamics and the control part. Interesting properties of the behavior of the system under attack can also be formally proved by theorem proving. The INTO-CPS framework has been used for co-simulation, and the methodology is applied to the Line follower robot case study of the INTO-CPS project. The theorem prover of PVS has been used for deriving formal proofs of invariants of the system under attack.