Trick or Heat? Manipulating Critical Temperature-Based Control Systems Using Rectification Attacks

TL;DR

This paper reveals security vulnerabilities in temperature control systems caused by physical-level attacks exploiting rectification effects in analog sensors, demonstrating potential safety risks and proposing a prototype anomaly detector for mitigation.

Contribution

It uncovers a hardware-level vulnerability in temperature sensors used in critical systems and introduces a low-cost anomaly detection solution to enhance security.

Findings

Adversaries can manipulate sensor readings without system tampering

Rectification effects in amplifiers can be exploited for control manipulation

Proposed anomaly detector improves system security

Abstract

Temperature sensing and control systems are widely used in the closed-loop control of critical processes such as maintaining the thermal stability of patients, or in alarm systems for detecting temperature-related hazards. However, the security of these systems has yet to be completely explored, leaving potential attack surfaces that can be exploited to take control over critical systems. In this paper we investigate the reliability of temperature-based control systems from a security and safety perspective. We show how unexpected consequences and safety risks can be induced by physical-level attacks on analog temperature sensing components. For instance, we demonstrate that an adversary could remotely manipulate the temperature sensor measurements of an infant incubator to cause potential safety issues, without tampering with the victim system or triggering automatic temperature alarms. This attack exploits the unintended rectification effect that can be induced in operational and instrumentation amplifiers to control the sensor output, tricking the internal control loop of the victim system to heat up or cool down. Furthermore, we show how the exploit of this hardware-level vulnerability could affect different classes of analog sensors that share similar signal conditioning processes. Our experimental results indicate that conventional defenses commonly deployed in these systems are not sufficient to mitigate the threat, so we propose a prototype design of a low-cost anomaly detector for critical applications to ensure the integrity of temperature sensor signals.