Among those acts of cyberwar was an unprecedented attack on Ukraine's power grid in 2016, one that appeared designed to not merely cause a blackout, but to inflict physical damage on electric equipment. The document charged six hackers working for Russia's GRU military intelligence agency with computer crimes related to half a decade of cyberattacks across the globe, from sabotaging the 2018 Winter Olympics in Korea to unleashing the most destructive malware in history in Ukraine.

Earlier this week, the US Department of Justice unsealed an indictment against a group of hackers known as Sandworm.