Israel’s Ben Gurion University of the Negev has shown how fluctuations in the current flow “propagated through the power lines” could be used to covertly steal highly sensitive data. The latest technique involves controlling the CPU utilization of an air-gapped computer using a specially designed pattern to transfer data hints in binary form. Attackers can exfiltrate data from the computer at a speed of 10 to 1,000 bits-per-second, depending upon their approach. The slower speed is achieved in “phase-level powerhammering” that can be exploited from the outside electrical service panel of a building.
Source: https://thehackernews.com/2018/04/hacking-airgap-computers.html