Recent results from the Ben-Gurion University of Negev have confirmed the harmful powers of a data-stealing drone. The device’s built-in cameras outmaneuvered safeguarded systems by focusing on a computer's LED hard drive light.

Although this flickering light practically goes unnoticed, its silent blinks were actually communicating an optical stream containing all the machine's most coveted data to the small spy quadcopter. The drone can receive this information even through a closed window, as long as the transmitting computer is within sight.

Often times, guarded computers go through a layer of security known as an air gap, which physically isolates the device so it’s incapable of connecting to a public network. This method is usually applied to highly sensitive computers, shielding them from dangerous internet hackers.

The team at Ben-Gurion’s cybersecurity lab was able to bypass the security measures of air-gapped computers and gain access to the previously isolated systems. First, a form of malware must be planted within the target device. Once infected, the attacker can then control the flicker rate of the LED, reaching a speed that surpasses the capabilities of human visual perception.

"Our method compared to other LED exfiltration is unique, because it is also covert," says Dr. Mordechai Guri, head of R&D at the Cybersecurity Research Center. "The hard drive LED flickers frequently, and therefore the user won't be suspicious about changes in its activity."

Confidential data is leaked through this quick, LED flicker rate. Private information can be encoded and transmitted over the LED signals, which are then captured by remote cameras and light sensors on the flying quadcopter.

The researchers have detailed a few countermeasures to block the LED transfer of data. By situating air-gapped devices away from windows or installing glass specifically designed to cover light flashes, the spy drone will not receive the sensitive material. Another viable option exists within protective software. Certain programs can access a computer's hard drive at random intervals in order to create noise. This will jam any attempt for a message to be sent via the computer's LED.

There is one last countermeasure the team describes, and it appears to be the simplest solution – physically cover the hard drive LED. By using an ordinary piece of tape to obscure the flickering light, you could halt the most advanced spy drones flying around today.