How Hackers Can Spy On You By “Listening” To LCD Screens


You might have come across the term side-channel attacks while reading news articles on Spectre and Meltdown. These exploits were possible due to the way Speculative Execution was implemented in Intel CPUs. Here, I’ll be telling you a new type of “physical” side-channel attack.

In such an attack, the hackers can steal the information stored on your computer by measuring the effects of the same on the physical environment. Dubbed Synesthesia, this specific exploit measures the “acoustic leakage from LCD screens.” LCD screens with both CCFL and LED backlights are affected.

Proposed by the security researchers from the University of Michigan, University of Pennsylvania, Tel Aviv University, Cornell Tech, and Columbia University, this attack also uses adjacent microphones embedded in webcams or some computer screens.

In their experimental setup, the researchers created a simple program that displayed patterns of alternating black and white color — the zebra pattern. They were able to relate the changes in zebra patterns with the changes in the acoustic signature. They were also able to narrow down the leakage source to the component supplying power to the monitor’s digital board.

microphone sample

The researchers found that the mobile phones, smart speakers, and distant microphones can also capture this leakage. Moreover, the leakage can also be analyzed from archived audio samples, video calling samples, and audio recordings stored by smart speakers in the cloud.

The researchers further used machine learning to train a custom model that deduced the screen’s content. Concluding their paper, they’ve said that by successfully simulating such an attack, one can get to know on-screen activities on a screen.

You can read all the technical details in this extensive research paper.

Also Read: Linux Creator On Intel CPU Bugs: “It’s Unfair. We Have To Fix Someone Else’s Problems”
Adarsh Verma

Adarsh Verma

Fossbytes co-founder and an aspiring entrepreneur who keeps a close eye on open source, tech giants, and security. Get in touch with him by sending an email — [email protected]
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