Scientists have learned to detect a wire that's running through a laptop microphone

Scientists have learned to detect a wire that's running through a laptop microphone

Researchers from the National University of Singapore and the University of Yeonsa in South Korea have developed a method to detect the hidden activation of the microphone on a laptop, using Raspberry Pi 4, an amplifier and a programmable receiver to create a prototype device called TickTock that can detect the activation of the microphone with harmful or spy software to audition the victim.

The method of determining the hidden activation of the laptop is relevant because it is not easy and not always clear when it works. The technique proposed is that in the course of operating the microphone circuit, which transmits tactical signals to the digital converter, it emits a specific background signal that can be captured and separated from other noises. When the microphone-specific electromagnetic radiation can be detected, it can be concluded that a recording is being made.

The TickTock device needs to be adapted to different laptop models because the radiation pattern can vary according to the sound chip used. In addition, researchers have had to filter noise from other electrical circuits and take into account the signal change depending on the connection. However, the device has been able to adapt 27 of the 30 laptops tested to determine the activity of the microphone, including the Lenovo, Fujitsu, Toshiba, Samsung, HP, Asus and Dell models. However, on Apple MacBook 2014, 2017 and 2019 releases, it has not been possible to determine the activation of the microphone in this way.

Researchers have also tried to use their design for other types of devices, such as smartphones, tablets, smart columns and USB cameras. Of the 40 tested devices, only 21 were able to detect the activation of the microphone, which is due to the use of analog microphones instead of digital, other connections and shorter conductors that emit an electromagnetic signal.