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LaserShark: Establishing Fast, Bidirectional Communication into Air-Gapped Systems

Niclas Kühnapfel
Stefan Preußler
Maximilian Noppel
Thomas Schneider
Konrad Rieck
Christian Wressnegger

December 06, 2021

Physical isolation, so called air-gapping, is an effective method for protecting security-critical computers and networks. While it might be possible to introduce malicious code through the supply chain, insider attacks, or social engineering, communicating with the outside world is prevented. Different approaches to breach this essential line of defense have been developed based on electromagnetic, acoustic, and optical communication channels. However, all of these approaches are limited in either data rate or distance, and frequently offer only exfiltration of data. We present a novel approach to infiltrate data to air-gapped systems without any additional hardware on-site. By aiming lasers at already built-in LEDs and recording their response, we are the first to enable a long-distance (25 m), bidirectional, and fast (18.2 kbps in & 100 kbps out) covert communication channel. The approach can be used against any office device that operates LEDs at the CPU’s GPIO interface.