In the wake of WannaCry, a new cyber threat has emerged from the NSA leak. Making use of previously exposed tools, Petya once again is engaged in another large scale attack. Important distinctions in this case, however, are that the attacks targeted mainly a specific country, and are used solely for destruction. While Petya may look like ransomware, it appears that despite a victim paying the ransom, there is no way to decrypt the files afterward.

http://blog.checkpoint.com/2017/07/03/brokers-shadows-part-2-analyzing-petyas-doublepulsarv2-0-backdoor/