(MobiCom'22) mmEve: Eavesdropping on Smartphone's Earpiece via COTS mmWave Device

Abstract

Earpiece mode of smartphones is often used for confidential communication. In this paper, we proposed a remote(>2m) and motion-resilient attack on smartphone earpiece. We developed an end-to-end eavesdropping system mmEve based on a commercial mmWave sensor to recover speech emitted from smartphone earpiece. The rationale of the attack is based on our observation that, soundwaves emitted from the smartphone’s earpiece have a strong correlation with reflected mmWaves from the smartphone’s rear. However, we find the recovered speech suffers from the sensor’s self-noise and smartphone user’s motion which limit attack distance to less than 2m, causing limited threats in real world. We modeled the motion interference under mmWave sensing and proposed a motion-resilient solution by optimizing the fitting function on I/Q plane. To achieve a practical attack with reasonable attack distance, we developed a GAN-based denoising scheme to eliminate the noise pattern of the sensor, which boosted the attack range to 6–8m. We evaluated mmEve with extensive experiments and find 23 different models of smartphones manufactured by Samsung, Huawei, etc. can be compromised by the proposed attack.