You may have encountered the term side-channel attacks when reading news about them Spectre and Meltdown. These vulnerabilities were possible due to the way Speculative Execution was implemented on Intel processors. Here, we will mention a new kind of "natural" side-channel attack.
In such an attack, hackers can steal the information stored on your computer by measuring the effects of the same in the physical environment. This particular holding is called Synesthesia, measures the "acoustic leak from LCD screens". CCFL backlit LCDs and LEDs are the ones affected.
As security researchers from Michigan University, Pennsylvania University, Tel Aviv University, Cornell Tech, and Columbia University suggest, this attack also uses nearby microphones embedded in web cams or computer screens.
In their experimental facility, the researchers created a simple program that showed patterns of alternating black and white - the zebra pattern. They were able to associate changes in zebra patterns with changes in the audio signature. They also had the ability to limit the leakage source to the component that feeds the monitor's digital board.
Researchers have found that mobile phones, smart speakers and remote microphones can also record this leak. In addition, leakage can be resolved from archived audio samples, video call samples, and recordings stored by smart speakers in the cloud.
Researchers used mechanical learning to train a custom model that drew the content of the screen. Closing their research, they said that with a successful simulation of such an attack, one may be aware of the activities on the screen.
You can read all the technical details in this extensive research form.