SonarSnoop : active acoustic side-channel attacks

Cheng, Peng and Bagci, Ibrahim Ethem and Roedig, Utz and Yan, Jeff (2020) SonarSnoop : active acoustic side-channel attacks. International Journal of Information Security, 19 (2). pp. 213-228. ISSN 1615-5270 (

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We report the first active acoustic side-channel attack. Speakers are used to emit human inaudible acoustic signals, and the echo is recorded via microphones, turning the acoustic system of a smart phone into a sonar system. The echo signal can be used to profile user interaction with the device. For example, a victim's finger movements can be inferred to steal Android unlock patterns. In our empirical study, the number of candidate unlock patterns that an attacker must try to authenticate herself to a Samsung S4 phone can be reduced by up to 70% using this novel acoustic side-channel. The attack is entirely unnoticeable to victims. Our approach can be easily applied to other application scenarios and device types. Overall, our work highlights a new family of security threats.