NotPetya (2017)

NotPetya was a destructive malware attack disguised as ransomware, deployed June 27, 2017 via a compromised update to M.E.Doc, a Ukrainian tax accounting software. Although it targeted Ukraine, it propagated globally via SMB and credential-theft mechanisms, causing the most destructive cyberattack in history by total economic damage. The U.S., UK, Australia, and Canada attributed the attack to GRU's Unit 74455 (Sandworm). It is the canonical reference point for catastrophic single-event cyber damage and the basis for the Merck v. Ace insurance war-exclusion litigation.