That means an attacker could even send invisible light signals to a faraway spy, albeit at a slower rate to avoid its covert blinks blurring into a visible signal. The malware could also make the hard drive LED blink so briefly, in fact, that it would be undetectable to human eyes, yet still registered by the light sensor.
A Siemens photodiode sensor was far better suited to their high-frequency light sensing needs, though, and allowed them to hit their 4,000 bits per second maximum transmission rate. They found that a typical smartphone camera can at most receive around 60 bits per second due to its lower frame rate, while a GoPro camera captured as much as 120 bits per second. They then tried using those rapid fire blinks to send messages to a variety of cameras and light sensors from an "infected" computer using a binary system of data encoding known as "on-off-keying," or OOK. The researchers found that when their program read less than 4 kilobytes from the computer's storage at a time, they could cause the hard drive's LED indicator to blink for less than a fifth of a millisecond. Every blink of its hard drive LED indicator can spill sensitive information to any spy with a line of sight to the target computer, whether from a drone outside the window or a telescopic lens from the next roof over. If an attacker can plant malware on one of those systems-say, by paying an insider to infect it via USB or SD card-this approach offers a new way to rapidly pull secrets out of that isolated machine. A group of researchers at Ben-Gurion's cybersecurity lab has devised a method to defeat the security protection known as an “air gap,” the safeguard of separating highly sensitive computer systems from the internet to quarantine them from hackers. Robot-style demonstration of a very real espionage technique. That data-stealing drone, shown in the video below, works as a Mr. But in fact, that LED was silently winking out an optical stream of the computer’s secrets to the camera floating outside.
COMPUTER ON SCREEN LIGHTS UP BUT JUST KEEPS BLINKING WINDOWS
The pinpoint flickers, emitting from the LED hard drive indicator that lights up intermittently on practically every modern Windows machine, would hardly arouse the suspicions of anyone working in the office after hours. It soon trained its built-in camera on its target, a desktop computer's tiny blinking light inside a third-floor office nearby. A few hours after dark one evening earlier this month, a small quadcopter drone lifted off from the parking lot of Ben-Gurion University in Beersheba, Israel.