CybersecurityAir-gapped computer systems can be hacked by using heat: Researchers

Published 25 March 2015

Computers and networks are air-gapped – that is, kept approximately fifteen inches (40 cm) apart — when they need to be kept highly secure and isolated from unsecured networks, such as the public Internet or an unsecured local area network. Typically, air-gapped computers are used in financial transactions, mission critical tasks, or military applications. Israeli researchers have discovered a new method, called BitWhisper, to breach air-gapped computer systems. The new method enables covert, two-way communications between adjacent, unconnected PC computers using heat – meaning that hackers to hack information from inside an air-gapped network, as well as transmit commands to it.

Ben-Gurion University of the Negev (BGU) researchers have discovered a new method, called BitWhisper, to breach air-gapped computer systems. The new method enables two-way communications between adjacent, unconnected PC computers using heat.

The research, conducted by Mordechai Guri, Ph.D., is part of an ongoing focus on air-gap security at the BGU Cyber Security Research Center. Computers and networks are air-gapped when they need to be kept highly secure and isolated from unsecured networks, such as the public Internet or an unsecured local area network. Typically, air-gapped computers are used in financial transactions, mission critical tasks, or military applications.

According to the researchers, “The scenario is prevalent in many organizations where there are two computers on a single desk, one connected to the internal network and the other one connected to the Internet. BitWhisper can be used to steal small chunks of data (for example, passwords) and for command and control.

View BitWhisper video demo.

A release from American Associates, Ben-Gurion University of the Negev reports that BGU’s BitWhisper bridges the air-gap between the two computers, approximately fifteen inches (40 cm) apart and which are infected with malware, by using their heat emissions and built-in thermal sensors to communicate. It establishes a covert, bi-directional channel by emitting heat from one PC to the other in a controlled manner. By regulating the heat patterns, binary data is turned into thermal signals. In turn, the adjacent PC uses its built-in thermal sensors to measure the environmental changes. These changes are then sampled, processed, and converted into data.

“These properties enable the attacker to hack information from inside an air-gapped network, as well as transmit commands to it,” the BGU researchers explain. “Only eight signals per hour are sufficient to steal sensitive information such as passwords or secret keys. No additional hardware or software is required. Furthermore, the attacker can use BitWhisper to directly control malware actions inside the network and receive feedback.”

Guri, a student researcher in BGU’s Department of Information Systems Engineering, is working under Prof. Yuval Elovici, director of the Cyber Security Research Center. He recently received the prestigious 2015-2016 IBM Ph.D. Fellowship Award.