Wcry uses weapons-grade exploit published by the NSA-leaking Shadow Brokers.
A highly virulent new strain of self-replicating ransomware shut down computers all over the world, in part by appropriating a National Security Agency exploit that was publicly released last month by the mysterious group calling itself Shadow Brokers.
The malware, known as Wanna, Wannacry, or Wcry, has infected at least 75,000 computers, according to antivirus provider Avast. AV provider Kaspersky Lab said organizations in at least 74 countries have been affected, with Russia being disproportionately affected, followed by Ukraine, India, and Taiwan. Infections are also spreading through the United States. The malware is notable for its multi-lingual ransom demands, which support more than two-dozen languages.
https://arstechnica.com/security/2017/05/an-nsa-derived-ransomware-worm-is-shutting-down-computers-worldwide/