Power-Based Security Monitoring: Non-Invasive Detection of Task Execution Violations in Real-Time Systems

Key Speaker

Abstract

Modern safety-critical systems, from centralized automotive Electrical/Electronic (E/E) architectures to distributed cyber-physical deployments, are increasingly reliant on Real-Time Operating Systems (RTOSs) to guarantee timing determinism. However, these systems face growing security threats where attackers can subvert traditional defense methods to mask malicious activity. This paper presents Power-Based Schedule Verification (PBSV), a novel, non-invasive security monitoring methodology that detects task execution violations, specifically, task overruns and underruns through power consumption side-channels.

Unlike invasive software monitors that share the attack surface with the target, our approach utilizes an out-of-band side-channel monitor to establish a trust anchor grounded in physical energy consumption. We introduce an algorithm that reconstructs the runtime schedule from raw power traces, leveraging the distinct RTOS idle state as ground-truth anchor. This is compared against a formal Workload Specification defining the Best Case Execution Time (BCET) and Worst Case Execution Time (WCET). This methodology was validated on an STM32 Microcontroller, and our framework successfully detects timing violations indicative of logic bypasses or unauthorized code execution, demonstrating a robust ”correctness-by-observation” mechanism.

Authors

1. Mayukh Haldar mhaldar@uwaterloo.ca (University of Waterloo)
2. Jenish Patel j347pate@uwaterloo.ca (University of Waterloo)
3. Sebastian Fischmeister sfischme@uwaterloo.ca (University of Waterloo)

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