Ransomware asks users to pay up before letting them start Windows

A new ransomware variant prevents infected computers from loading Windows by replacing their master boot record (MBR) and displays a message asking users for money, according to security researchers from Trend Micro.

"Based on our analysis, this malware copies the original MBR and overwrites it with its own malicious code," said Cris Pantanilla, a threat response engineer at Trend Micro, in a blog post on Thursday. "Right after performing this routine, it automatically restarts the system for the infection take effect."

The MBR is a piece of code that resides in the first sectors of the hard drive and starts the boot loader. The boot loader then loads the OS.

Instead of starting the Windows boot loader, the rogue MBR installed by the new ransomware displays a message that asks users to deposit a sum of money into a particular account via an online payment service called QIWI, in order to receive an unlock code for their computers.

"This code will supposedly resume operating system to load and remove the infection," Pantanilla said. "When the unlock code is used, the MBR routine is removed."