CAUTIOUS COMPUTER USERS put a piece of tape over their webcam. Truly paranoid ones worry about their devices’ microphones—some even crack open their computers and phones to disable or remove those audio components so they can’t be hijacked by hackers. Now one group of Israeli researchers has taken that game of spy-versus-spy paranoia a step further, with malware that converts your headphones into makeshift microphones that can slyly record your conversations.

Researchers at Israel’s Ben Gurion University have created a piece of proof-of-concept code they call “Speake(a)r,” designed to demonstrate how determined hackers could find a way to surreptitiously hijack a computer to record audio even when the device’s microphones have been entirely removed or disabled. The experimental malware instead repurposes the speakers in earbuds or headphones to use them as microphones, converting the vibrations in air into electromagnetic signals to clearly capture audio from across a room.

“People don’t think about this privacy vulnerability,” says Mordechai Guri, the research lead of Ben Gurion’s Cyber Security Research Labs. “Even if you remove your computer’s microphone, if you use headphones you can be recorded.”

It’s no surprise that earbuds can function as microphones in a pinch, as dozens of how-to YouTube videos demonstrate. Just as the speakers in headphones turn electromagnetic signals into sound waves through a membrane’s vibrations, those membranes can also work in reverse, picking up sound vibrations and converting them back to electromagnetic signals. (Plug a pair of mic-less headphones into an audio input jack on your computer to try it.)

Read the rest at Wired.