WannaCry

WannaCry attacks were the biggest ransomware attacks and occurred in May 2017. WannaCry made use of a vulnerability in the Windows OS, first identified by the NSA, and then made publicly available through Shadow Brokers. It was designed to exploit a vulnerability in Windows SMBv1 and SMBv2, so that one moves laterally within networks. By May 24, 2017, more than 200,000 computer systems were infected in 150 countries.