CyFence: Securing Cyber-Physical Controllers via Trusted Execution Environment

2024-04-01

IEEE Transactions on Emerging Topics in Computing

AI Summary

Security-critical cyber-physical systems (CPS) are vulnerable to logic-based attacks such as sensor spoofing and actuator hijacking. To address this, we propose CyFence—a novel architecture that embeds CPS physical dynamic semantics into the closed-loop controller for online, real-time compliance verification of control actions. By leveraging ARM TrustZone as a trusted execution environment (TEE), CyFence ensures the integrity and immutability of the verification logic itself, thereby enabling simultaneous attack detection and behavioral validation. Our approach comprises three key components: (1) physics-informed semantic modeling of CPS dynamics, (2) a lightweight, real-time verification mechanism, and (3) hardware-in-the-loop (HIL) validation. Evaluated on a production-grade active braking digital controller, CyFence demonstrates robust resilience against diverse logic attacks while incurring an average computational overhead of less than 0.8%, significantly enhancing the depth and reliability of CPS defense.

Technology Category

• Computer Vision: Adversarial Attacks & Robustness
• Cognitive Modeling & Cognitive Systems: Agent Architectures
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Security and Privacy: Cyber-crime defenses and forensics
• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures
• User Modeling, Personalization and Recommendation: Attacks and countermeasures in recommendation systems

Abstract

In the last decades, Cyber-physical Systems (CPSs) have experienced a significant technological evolution and increased connectivity, at the cost of greater exposure to cyber-attacks. Since many CPS are used in safety-critical systems, such attacks entail high risks and potential safety harms. Although several defense strategies have been proposed, they rarely exploit the cyber-physical nature of the system. In this work, we exploit the nature of CPS by proposing CyFence, a novel architecture that improves the resilience of closed-loop control systems against cyber-attacks by adding a semantic check, used to confirm that the system is behaving as expected. To ensure the security of the semantic check code, we use the Trusted Execution Environment implemented by modern processors. We evaluate CyFence considering a real-world application, consisting of an active braking digital controller, demonstrating that it can mitigate different types of attacks with a negligible computation overhead.

Problem

• Securing cyber-physical controllers against cyber-attacks
• Enhancing resilience via semantic behavior checks
• Leveraging Trusted Execution Environment for security

Innovation

• Uses Trusted Execution Environment for security
• Adds semantic check for expected behavior
• Mitigates attacks with low computation overhead