May 2017
On May 2017, multiple companies and organisations around the world were hit by variations of a crypto-ransomware dubbed WannaCry / WannaCrypt / WanaCrypt0r / WCrypt / WCRY (here on called WannaCry for simplicity). The ransomware also acts as a worm and once it infects a system, it then self-propagates throughout the rest of the network. The ransomware campaign caused chaos due to its massive distribution, affecting more than 150 countries and infecting over 230,000 systems. Interestingly the attack was mounted on Friday 12th May 2017, just before the weekend, making it very difficult for companies and organisations to quickly react and resolve the crisis.
https://www.enisa.europa.eu/publications/info-notes/wannacry-ransomware-outburst
