LCD pwn System: How to modulate screen brightness to covertly transmit data from an air-gapped computer... slowly

2020-02-06 06:09

The researchers who developed this screen illumination scheme, Mordechai Guri, Dima Bykhovsky, and Yuval Elovici, have done previous side channel transmission work: exploring ultrasonic data leakage, an escape route for Faraday-caged computers; computer-smartphone data exchange via electrical fields; acoustic signaling using fan modulation; and covert signaling via keyboard lights, among other techniques.

The latest paper from the trio, presented at the 12th CMI Conference on Cybersecurity and Privacy in November and just distributed via ArXiv, is called "BRIGHTNESS: Leaking Sensitive Data from Air-Gapped Workstations via Screen Brightness."

There's a further assumption that the object of the attack isn't to capture information displayed on screen and that the camera doesn't have a direct view of the screen.

"Malware on a compromised computer can obtain sensitive data, and modulate it within the screen brightness, invisible to users."

You can see just how tediously slow this is in a YouTube video showing the attack capturing text of A.A. Milne's "Winnie-the-Pooh" from the screen flicker coming off a PC in an office adjacent to a video camera.

News URL

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