Hackers tied to Russia’s GRU targeted the US grid for years

have targeted the United States power grid—and even successfully breached American electric utilities—only the Russian military intelligence group known as Sandworm has been brazen enough to trigger actual blackouts, shutting the lights off in Ukraine in 2015 and 2016. Now one grid-focused security firm is warning that a group with ties to Sandworm’s uniquely dangerous hackers has also been actively targeting the US energy system for years.

On Wednesday, industrial cybersecurity firm Dragos published its annual report on the state of industrial control systems security, which names four new foreign hacker groups focused on those critical infrastructure systems. Three of those newly named groups have targeted industrial control systems in the US, according to Dragos. But most noteworthy, perhaps, is a group that Dragos calls Kamacite, which the security firm describes as having worked in cooperation with the GRU’s Sandworm. Kamacite has in the past served as Sandworm’s “access” team, the Dragos researchers write, focused on gaining a foothold in a target network before handing off that access to a different group of Sandworm hackers, who have then sometimes carried out disruptive effects. Dragos says Kamacite has repeatedly targeted US electric utilities, oil and gas, and other industrial firms since as early as 2017.