What is the WannaCry Ransomware Attack? | UpGuard

WannaCry was a 2017 global cryptoworm ransomware campaign that exploited the NSA-derived EternalBlue SMB vulnerability and leveraged the DoublePulsar backdoor to self-propagate across Windows systems, infecting an estimated 200,000+ machines in 150 countries and causing widespread disruption (notably to the UK NHS); the report describes the malware's behavior, kill-switch discovery, Microsoft patches (MS17-010), attribution to North Korean-linked Lazarus actors, impact, and recommended mitigations such as prompt patching and backups.