Data-Driven Covert-Attack Strategies and Countermeasures for Cyber-Physical Systems

This paper studies covert-attacks for cyber-physical systems (CPS) under conditions that adversaries do not explicitly know the system characteristic matrices (A, B, C). Covert-attacks are considered as undetectable type of cyber-attacks. We propose and develop conditions under which adversaries are capable of performing covert-attacks for CPS only by utilizing Markov parameters of the system, which are assumed to be known to adversaries. In order to demonstrate the execution of proposed covert-attacks in this paper, a specific sensor attack signal which should be accompanied by an actuator attack is introduced based on Markov parameters of the CPS. The minimum number of sensors which should be attacked to perform covert-attacks while only one actuator is manipulated by adversaries is investigated. The latter can be used by adversaries to select a specific actuator to compromise. In order to make the CPS more secure against covert-attacks, we propose and develop a coding scheme which increases the number of required sensors that should be compromised during a covert-attack. Hence, if the proposed coding scheme is utilized, adversaries need to compromise all the output communication channels of CPS to perform covert-attacks. An illustrative simulation case study is provided to demonstrate the effectiveness of the proposed covert-attack method and the coding scheme.