SPEAKE(a)R: Turn Speakers to Microphones for Fun and Profit [pdf] (2017)

https://www.usenix.org/system/files/conference/woot17/woot17-paper-guri.pdf

Article

  • Research shows PC speakers can be repurposed as microphones for covert audio capture.
  • Exploits jack retasking in audio hardware to record even with mic disabled.
  • Demonstrates audio exfiltration from air-gapped machines via speakers.
  • Attack requires malware on the target machine to retask audio output.

Discussion

  • antirez notes many physical processes are invertible: motors, LEDs, Peltier cells, speakers.
  • Commenters share personal anecdotes: fishing boats using deck speakers as intercoms, recording via headphones as kids.
  • Drive-thru kiosks confirmed to use this same speaker-as-mic principle commercially.
  • One commenter found a hidden wired speaker under a DC hotel bathroom sink labeled ‘F.B.I.’

Discuss on HN


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Added Apr 20, 2026
Modified Apr 20, 2026