Hackers can use AC power lines as a covert channel to extract data from air-gapped networks through a malicious code that controls power consumption of a computer by regulating CPU core utilization and modulates the data based on power fluctuations. Security researchers from the University of the Negev, Israel presented this new type of covert channel dubbed PowerHammer, that allows. attackers to extract. data from. air-gap networks. The data might be files, encryption keys, credential tokens, or passwords.”]
Source: https://gbhackers.com/powerhammer-air-gapped-computer/