Security researchers at Israel’s Ben Gurion University have created a proof-of-concept exploit that lets them turn headphones into microphones to secretly record conversations. The PoC, called “Speake(a)r,” first turned headphones connected to a PC into microphones and then tested the quality of sound recorded by a microphone vs. headphones on a target PC. In short, the headphones were nearly as good as an unpowered microphone at picking up audio in a room.
The hack is fairly ingenious. It essentially “retasks” the RealTek audio codec chip output found in many desktop computers into an input channel. This means you can plug your headphones into a seemingly output-only jack and hackers can still listen in. “Our experiments demonstrate that intelligible audio can be acquired through earphones and can then be transmitted distances up to several meters away,” wrote researcher Mordecai Guri. “In addition, we showed that the same setup achieves channel capacity rates close to 1 Kbps in a wide range of frequencies.”