The Petya ransomware causes a blue screen of death (BSoD) by overwriting the MBR and leaving a ransom note at system startup. When the victim tries to reboot the PC, it will impossible to load the OS, even in Safe Mode. Victims receive an email that appears to be from an applicant seeking a position in a company, it includes a link to a Dropbox folder that contains its alleged CV. The ransom note requests the payment of 0.99 Bitcoins (nearly US$430), but the price would be doubled if the payment is not completed within a deadline.”]
Source: http://securityaffairs.co/wordpress/45678/malware/petya-ransomware.html