Experimental and Theoretical Study of Acoustic Injection Attacks on MEMS Accelerometer

In this paper, by theoretical analysis and experiments, we demonstrate that the output of Microelectromechanical systems (MEMS) accelerometer is nonlinear when we inject resonant sinusoidal acoustic wave with linearly increasing amplitude. We simulate the physics of acoustic injection attacks on MEMS accelerometer. However, the output of MEMS accelerometer does not follow the linear input due to the saturated amplifier. The time-domain response and time-frequency image of acoustic attack are obtained respectively by MATLAB ordinary differential equations solver (ODE45) and short time Fourier transform (STFT). In the experiment, we firstly perform frequency sweeping attack on ADXL103. The resonant frequency of ADXL103 is determined to be approximately 5.15kHz. The failure of the ADXL103 is primarily due to the signal clipping of the amplifier. Then we perform amplitude sweeping attack on ADXL103, and the angle with the direction of gravity is 0°/30°/45°/60°/90° respectively. The resonant sinusoidal acoustic signal is amplitude modulated, and the peak-to-peak voltage of the signal linearly increases from 0 V to 3 V, resulting in a nonlinear output. The maximum change in the acceleration is 3.69 m/s2, and the minimum change is 0.44 m/s2. The experimental results in the paper confirm the simulation results.