Annabelle & MBRLock ransomware

Annabelle & MBRLock ransomware new evolution that directly infecting the Windows computers Master Boot Record (MBR) which Prevent Operating system to loading and avoid the security scan.

None of the ransomware tool work Since the Operating system stop booting and this technique is kept increasing nowadays and this technique also used by PETYA ransomware last year.

Ransomware evolution is dramatically increasing nowadays and the authors are using various new tactics to bypass the security control and maintain its persistence.

MBR infection is an indication of deep infection in terms of controlling the infected computers and maintains more persistence to do its further encryption operation.

A master boot record (often shortened as MBR) is a kind of boot sector stored on a hard disk drive or other storage devices that contain the necessary computer code to start the boot process.

MBR based Ransomware infection takes place when the user restarts the system once the ransomware copies the original MBR and overwrites it with its own malicious code.

Since the MBR executes every time a computer is started, an MBR infection can be extremely dangerous.

Annabelle & MBRLock Ransomware

Annabelle Infection with Master Boot Record

Annabelle ransomware is capable of destroying all the hard disk that connected with the computers by infecting the Master Boot Record.

After the infection, it attempts to disable the firewall and it is capable of terminates the list of processes including the security-related programs.

Initially, it spreading via spam email and connected USB drives and overwrites the MBR with its own code.

It calls a DLL CreateFileA to take over the infected systems physical drive where it will write  0x800 bytes on each physical drive.

According to QuickHeal Researchers, termination of this process will result in a termination of Windows as well. Calling RtlSetProcessIsCritical (1, 0, 0) will set the process as critical.Later it calls RtlSetProcessIs function.

Eventually, it calls shutdown.exe with parameter -r -f -t 0(r-shutdown& restart) to restart the system and -t  to force running applications.

Finally, once the system restarted then the Malware gets executed and encrypt the desk file and displays the ransom notes.

This Annabelle ransomware demand 0.1 Bitcoin as a ransom amount also it displays the countdown to pay the ransom amount and if it exceeds then the new screen will be displayed that is an indication of completely infection system unusable ever and it destroys all hard disk data.

MBRLock Infection with Master Boot Record

MBRLock initially discovered on Feb 2018 which is another ransomware that abuses the Master Boot Record of the victim’s computer.

It using createfile API  to read the physical drive Then it calls SetFilePointer and sets the offset to zero of the physical drive to access MBR.

It reads 0x200 bytes of the physical drive in memory and writes on another sector for restoring in future and replaces the original MBR with the malicious code.


Later malware writes the malicious code in zero offsets so malicious code executes every time when system reboot then malware calls ExitWindowEx API to restart the system.

Finally, it displays the ransom notes that says send 30 yuan to the 2055965068 qq address in order to get access to their computer again”.

Annabelle & MBRLock ransomware