An anonymous reader writes: Researchers from the Ben-Gurion University of the Negev in Israel have developed malware that when installed on a router or a switch can take control over the device's LEDs and use them to transmit data in a binary format to a nearby attacker, who can capture it using simple video recording equipment. The attack is similar to the LED-it-GO attack developed by the same team, which uses a hard drive's blinking LED to steal data from air-gapped computers. Because routers and switches have many more LEDs than a hard drive, this attack scenario is much more efficient, as it can transmit data at about the same speed, but multiplied by the number of ports/LEDs. Researchers say they were able to steal data by 1000 bits/ per LED, making this the most efficient attack known to date. The attack worked best when coupled with optical sensors, which are capable of sampling LED signals at high rates, enabling data reception at a higher bandwidth than other typical video recording equipment. A video of the attack is available here.