EM Eavesdropping Attack on Digital Microphones Using Pulse Density Modulation
a year ago
- #side-channel-attack
- #acoustic-eavesdropping
- #cybersecurity
- Introduction of a novel electromagnetic (EM) side-channel attack for acoustic eavesdropping on electronic devices.
- Targets modern digital microelectromechanical systems (MEMS) microphones using pulse-density modulation (PDM).
- Attack allows retrieval of original audio via FM demodulation using standard radio receivers without device tampering.
- Real-world evaluation shows up to 94.2% accuracy in recognizing spoken digits from 2 meters away behind a 25 cm concrete wall.
- Speech-to-text APIs achieve a maximum of 14% transcription error rate in recovering the Harvard Sentences dataset.
- Attack feasible with a cheap and stealthy copper tape antenna.
- Current defenses like resampling are limited; a new hardware defense based on clock randomization is proposed.