Security researchers at Ben Gurion University in Israel have found a way to retrieve data from an air-gapped computer using only heat emissions and a computer’s built-in thermal sensors. The method would allow attackers to surreptitiously siphon passwords or security keys from a protected system and transmit the data to an internet-connected system that’s in close proximity and that the attackers control. They could also use the internet-connected system to send malicious commands to the air-gapped system using the same heat and sensor technique. The proof-of-concept attack requires both systems to first be compromised with malware. And currently, the attack allows for just eight bits of data to be reliably transmitted over an hour—a rate that is sufficient for an attacker to transmit brief commands or siphon a password or secret key but not large amounts of data. It also works only if the air-gapped system is within 40 centimeters (about 15 inches) from the other computer the attackers control. But the researchers, at Ben Gurion’s Cyber Security Labs, note that this latter scenario is not uncommon, because air-gapped systems often sit on desktops alongside Internet-connected ones so that workers can easily access both.

» Kim Zetter |