Passivity framework for modeling, mitigating, and composing attacks on networked systems

Cyber-physical systems (CPS) consist of a tight coupling between cyber (sensing and computation) and physical (actuation and control) components. As a result of this coupling, CPS are vulnerable to both known and emerging cyber attacks, which can degrade the safety, availability, and reliability of the system. A key step towards guaranteeing CPS operation in the presence of threats is developing quantitative models of attacks and their impact on the system and express them in the language of CPS. Traditionally, such models have been introduced within the framework of formal methods and verification. In this talk, we present a control-theoretic modeling framework. We demonstrate that the control-theoretic approach can capture the adaptive and time-varying strategic interaction between the adversary and the targeted system. Furthermore, control theory provides a common language in which to describe both the physical dynamics of the system, as well as the impact of the attack and defense. In particular, we provide a passivity-based approach for modeling and mitigating jamming and wormhole attacks. We demonstrate that passivity enables composition of multiple attack and defense mechanisms, allowing characterization of the overall performance of the system under attack. Our view is that the formal methods and the control-based approaches are complementary.