Infecting the Master Boot Record (MBR) and encrypting files is nothing new in the world of malicious programs. Back in 1994, the virus OneHalf emerged that infected MBRs and encrypted the disk contents. However, that virus did not extort money. In 2011, MBR blocker Trojans began spreading (Trojan-Ransom.Win32.Mbro) that infected the MBR and prevented the operating system from loading further. The victim was prompted to pay a ransom to get rid of the problem. It was easy to treat a system infected by these blocker Trojans because, apart from the MBR, they usually didn’t encrypt any data on the disk.
Today, we have encountered a new threat that’s a blast from the past. The Petya Trojan (detected by Kaspersky Lab products as Trojan-Ransom.Win32.Petr) infects the MBR preventing normal system loading, and encrypts the Master File Table (MFT), an important part of the NT file system (NTFS), thus preventing normal access to files on the hard drive.