Various ways have already been described to transfer data from computers without a network connection or direct physical contact (for example, using sounds outside the audible spectrum), but in this case, perhaps the most sophisticated example is described. Researchers have found a way to steal data from computers without any connection - by monitoring the brightness of the display.
The approach involves a situation where a compromised computer makes subtle changes to the RGB color values ββon the LCD display, which the camera is able to track. Theoretically, an attacker could upload malware to the target system via a USB drive that would encode the transmission of data packets with a screen brightness change imperceptible to a human, and then use hacked security cameras nearby to intercept the necessary information.
Of course, this is not easy: the method assumes that the data thief will still have to hack into the victim's computer, install malware and, in addition, have cameras under his control that are within line of sight of the target system. This seemingly strange method can certainly be used by special services in some very rare specific cases, but it is very doubtful and inconvenient for ordinary attackers.
However, in the case of super-secure objects without access to an external network, the possibility of such a non-trivial hack will also have to be considered. At a minimum, do not place cameras within the line of sight of the screen in order to exclude the slightest possibility of such a scenario.
Source: 3dnews.ru