Can Data be Stolen from Your Computer Using Screen Brightness? New Research Creates Panic!

A new research reveals that hackers can exfiltrate sensitive data from your computer by simply changing the brightness of the screen. This is done from a physically isolated air-gapped computer that can't connect wirelessly or physically with other computers or network devices and rely on exploiting little-noticed emissions of a computer's components such as light, sound, heat, radio frequencies, or ultrasonic waves, and even using the current fluctuations in the power lines.

"This covert channel is invisible, and it works even while the user is working on the computer. Malware on a compromised computer can obtain sensitive data (e.g., files, images, encryption keys, and passwords), and modulate it within the screen brightness, invisible to users," researchers said.

Explaining further, they said the attacker uses small changes in the LCD screen brightness, which remains invisible to the naked eye, to covertly modulate binary information in morse-code like patterns. "In LCD screens each pixel presents a combination of RGB colors which produce the required compound color. In the proposed modulation, the RGB color component of each pixel is slightly changed. These changes are invisible, since they are relatively small and occur fast, up to the screen refresh rate. Moreover, the overall color change of the image on the screen is invisible to the user."

The attacker can collect this data stream using video recording of the compromised computer's display, taken by a local surveillance camera, smartphone camera, or a webcam and then reconstruct exfiltrated information using image processing techniques.