Non-Intrusive Runtime Monitoring Through Power Consumption to Enforce Safety and Security Properties in Embedded Systems

The increasing complexity and connectivity of modern em-
bedded systems highlight the importance of runtime monitoring to en-
sure correctness and security. This poses a significant challenge, since
monitoring tools can break extra-functional requirements such as timing
constraints. Non-intrusive program tracing through side-channel analy-
sis techniques have recently appeared in the literature and constitute
a promising approach. Existing techniques, however, exhibit important
limitations.
In this paper, we present a novel technique for non-intrusive program
tracing from power consumption, based on a signals and system analy-
sis approach: we view the power consumption signal as the output of a
system with the power consumption of training samples as input. Using
spectral analysis, we compute the impulse response to identify the sys-
tem; the intuition is that for the correct training sample, the system will
appear close to a system that outputs a shifted copy of the input signal,
for which the impulse response is an impulse at the position correspond-
ing to the shift. We also use the Control Flow Graph (CFG) from the
source code to constrain the classifier to valid sequences only, leading to
substantial performance improvements over previous works.
Experimental results confirm the effectiveness of our technique and show
its applicability to runtime monitoring. The experiments include tracing
programs that execute randomly generated sequences of functions as well
as tracing a real application developed with SCADE. The experimental
evaluation also includes a case-study as evidence of the usability of our
technique to detect anomalous execution through runtime monitoring.