Your Mic Leaks Too Much: A Double-Edged Sword for Security

Microphones are an integral part of a wide range of devices owing to their utility in communication and voice-controlled assistance. However, the downside to microphones' ubiquity is the increase in eavesdropping that lead to inference attacks, such as recovering passwords by merely recording ambient sounds. To overcome such attacks, researchers have proposed several microphone detection and deterrence methods. However, existing methods have several disadvantages such as lacking generalizability and requiring hardware modifications. In this paper, I examine the microphone security space by taking two past works as examples. Specifically, I demonstrate an attack that enables recreation of physical keys to unlock doors from recordings of sound of key insertion into the keyhole. Subsequently, I propose an eavesdropping detection technique utilizing electromagnetic leakage signals from microphone hardware which is generalizable across devices without requiring hardware changes. Finally, I present several open problems and their challenges towards achieving microphone security.