Security firm F-Secure has issued an alert on the Petya ransomware, sharing the results of its analysis about the threat. The malware encrypts the entire disk instead of encrypting files on the infected system like any other ransomware. The attack of a generic ransomware is very slow respect an attack based on the malware, this means that victims aware of the threat could act to limit the effects of the malware. Another effect is that the victim would need to use a machine different from the infected computer to pay the ransom.”]
Source: https://securityaffairs.co/wordpress/45882/malware/petya-ransomware-datails.html