SonarSnoop: Active Acoustic Side-Channel Attacks
This work reveals a new family of security threats for smartphone users, enabling attackers to steal sensitive information like unlock patterns through acoustic side-channels.
The authors tackled the problem of active acoustic side-channel attacks by using smartphone speakers and microphones as a sonar system to infer user interactions, such as finger movements, reducing Android unlock pattern candidates by up to 70% in tests on a Samsung S4.
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 phone unlock patterns. In our empirical study, the number of candidate unlock patterns that an attacker must try to authenticate herself to a Samsung S4 Android phone can be reduced by up to 70% using this novel acoustic side-channel. Our approach can be easily applied to other application scenarios and device types. Overall, our work highlights a new family of security threats.