A team of academics has successfully developed and tested malware that can exfiltrate data from air-gapped computers via power lines. The team from the Ben-Gurion University of the Negev in Israel named their data exfiltration technique PowerHammer. The malware is only an experiment and if ever deployed in the wild, such a tool would only be found in the arsenal of intelligence agencies and not something that normal users would see every day. Attackers intentionally alter CPU utilization levels to make the victim’s computer consume more or less electrical power.
Source: https://www.bleepingcomputer.com/news/security/researchers-create-malware-that-steals-data-via-power-lines/