Injected and Delivered: Fabricating Implicit Control over Actuation Systems by Spoofing Inertial Sensors
It addresses security vulnerabilities in actuation systems reliant on inertial sensors, posing risks to safety-critical applications, but is incremental as it builds on prior acoustic attack methods by considering realistic factors.
This work tackles the problem of controlling embedded MEMS inertial sensors in real systems using out-of-band acoustic signal injection, achieving effective manipulation in 17 out of 25 tested devices by exploiting sample rate drifts and developing methods like digital amplitude adjusting and phase pacing.
Inertial sensors provide crucial feedback for control systems to determine motional status and make timely, automated decisions. Prior efforts tried to control the output of inertial sensors with acoustic signals. However, their approaches did not consider sample rate drifts in analog-to-digital converters as well as many other realistic factors. As a result, few attacks demonstrated effective control over inertial sensors embedded in real systems. This work studies the out-of-band signal injection methods to deliver adversarial control to embedded MEMS inertial sensors and evaluates consequent vulnerabilities exposed in control systems relying on them. Acoustic signals injected into inertial sensors are out-of-band analog signals. Consequently, slight sample rate drifts could be amplified and cause deviations in the frequency of digital signals. Such deviations result in fluctuating sensor output; nevertheless, we characterize two methods to control the output: digital amplitude adjusting and phase pacing. Based on our analysis, we devise non-invasive attacks to manipulate the sensor output as well as the derived inertial information to deceive control systems. We test 25 devices equipped with MEMS inertial sensors and find that 17 of them could be implicitly controlled by our attacks. Furthermore, we investigate the generalizability of our methods and show the possibility to manipulate the digital output through signals with relatively low frequencies in the sensing channel.