Israeli researchers show how two air-gapped PCs placed in the same room can covertly exchange data via ultrasonic waves. The new technique works by reversing connected speakers (passive speakers, headphones, or earphones) into microphones by exploiting a specific audio chip feature. Researchers found that data can be exchanged over an air-gap computer a distance of eight meters away with an effective bit rate of 10 to 166 bit per second. It’s the first time Ben-Gurion researchers have come up with a covert hacking technique when the technique’s first time has come up.
Source: https://thehackernews.com/2018/03/air-gap-computer-hacking.html