Optimal Attack Strategies Subject to Detection Constraints Against Cyber-Physical Systems

• Published in: IEEE transactions on control of network systems Vol. 5; no. 3; pp. 1157 - 1168
• Main Authors: Chen, Yuan, Kar, Soummya, Moura, Jose M. F.
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.09.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Actuators; Algorithms; Attack helicopters; Bias; Cost function; Cyber-physical systems; Detectors; False alarms; fault detection; Kalman filters; optimal control; Probability; Remote control; Security; Statistical analysis; system design and analysis
• ISSN: 2325-5870; 2372-2533
• DOI: 10.1109/TCNS.2017.2690399

This paper studies an attacker against a cyber-physical system (CPS) whose goal is to move the state of a CPS to a target state while ensuring that his or her probability of being detected does not exceed a given bound. The attacker's probability of being detected is related to the non-negative bias induced by his or her attack on the CPS's detection statistic. We formulate a linear quadratic cost function that captures the attacker's control goal and establish constraints on the induced bias that reflect the attacker's detection-avoidance objectives. When the attacker is constrained to be detected at the false alarm rate of the detector, we show that the optimal attack strategy reduces to a linear feedback of the attacker's state estimate. In the case that the attacker's bias is upper bounded by a positive constant, we provide two algorithms-an optimal algorithm and a suboptimal, less computationally intensive algorithm-to find suitable attack sequences. Finally, we illustrate our attack strategies in numerical examples based on a remotely controlled helicopter under attack.