Rokku Ransomware

Also Known As: Rokku virus
Distribution: Low
Damage level: Severe

Rokku ransomware removal instructions

What is Rokku?

Rokku is a ransomware designed to stealthily infiltrate the system and encrypt various stored files. It adds a .rokku extension to each compromised file and, thus, it is easy to determine which ones are encrypted. 'README_HOW_TO_UNLOCK.html' and 'README_HOW_TO_UNLOCK.txt' files are then created and placed in each folder containing the encrypted files. README_HOW_TO_UNLOCK contains a message stating that the files have been encrypted.

The message encourages users to install the Tor browser and visit a URL address provided. This site supposedly contains step-by-step payment instructions that the user must follow. The ransom is 0.2403 Bitcoin (at time of research, equivalent to $100.29). Rokku demands a relatively small ransom, since many ransomware infections demand in the region of 0.5-1.5 Bitcoin ($208.51 - $625.53). In fact, the ransom can often exceed 5 Bitcoins. Rokku also allows users to decrypt one selected file free of charge. This supposedly assures victims that their remaining files will successfully be decrypted once payment is made. Unfortunately, at time of research, there were no tools capable of decrypting files compromised by Rokku ransomware. Therefore, the only solution to this problem is to restore your system/files from a backup.

Screenshot of a message encouraging users to contact the developers of Rokku ransomware to decrypt their compromised data:

Rokku decrypt instructions

Rokku shares similarities with other ransomware-type malware such as Locky, Cryptowall, Teslacrypt, Cerber, and Maktub. Although all have identical behavior (stealth system infiltration and file encryption), there are two main differences - the encryption algorithm used and size of ransom. Be aware that paying the ransom does not guarantee that your files will ever be decrypted. For this reason, victims should never attempt to contact cyber criminals or pay the ransom. In doing so, victims will merely support cyber criminals' malicious businesses. Research shows that ransomware is often distributed using peer to peer (P2P) networks, malicious email attachments, trojans, and fake software updates. Therefore, users should be cautious when downloading files from untrusted sources and when opening attachments sent from unrecognized email addresses. Using a legitimate anti-virus/anti-spyware suite and keeping your installed software up-to-date is paramount.


Rokku decryption file

Message presented in the 'README_HOW_TO_UNLOCK' .html and .txt files:

In order to unlock your files, follow the instructions bellow:
1. Download and install Tor Browser
2. After a successful installation, run Tor Browser and wait for its initialization.
3. Type in the address bar: http://zvnvp2rhe3ljwf2m.onion
4. Follow the instructions on the site.

Rokku 'Unlock Service' website:

Rokku Unlock Service

Rokku 'Decryption Website':

Rokku decryption site (sample 1) Rokku decryption site (sample 2) Rokku decryption site (sample 3)

Rokku ransomware removal:

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Quick menu:

Step 1

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup. Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings". Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Windows 8 Safe Mode with networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Step 2

Log in to the account infected with the Rokku virus. Start your Internet browser and download a legitimate anti-spyware program. Update the anti-spyware software and start a full system scan. Remove all entries detected.

If you cannot start your computer in Safe Mode with Networking, try performing a System Restore.

Video showing how to remove ransomware virus using "Safe Mode with Command Prompt" and "System Restore":

1. During your computer start process, press the F8 key on your keyboard multiple times until the Windows Advanced Options menu appears, and then select Safe Mode with Command Prompt from the list and press ENTER.

Boot your computer in Safe Mode with Command Prompt

2. When Command Prompt mode loads, enter the following line: cd restore and press ENTER.

system restore using command prompt type cd restore

3. Next, type this line: rstrui.exe and press ENTER.

system restore using command prompt rstrui.exe

4. In the opened window, click "Next".

restore system files and settings

5. Select one of the available Restore Points and click "Next" (this will restore your computer system to an earlier time and date, prior to the Rokku ransomware virus infiltrating your PC).

select a restore point

6. In the opened window, click "Yes".

run system restore

7. After restoring your computer to a previous date, download and scan your PC with recommended malware removal software to eliminate any remaining Rokku ransomware files.

To restore individual files encrypted by this ransomware, try using Windows Previous Versions feature. This method is only effective if the System Restore function was enabled on an infected operating system. Note that some variants of Rokku are known to remove Shadow Volume Copies of the files, so this method may not work on all computers.

To restore a file, right-click over it, go into Properties, and select the Previous Versions tab. If the relevant file has a Restore Point, select it and click the "Restore" button.

Restoring files encrypted by CryptoDefense

If you cannot start your computer in Safe Mode with Networking (or with Command Prompt), boot your computer using a rescue disk. Some variants of ransomware disable Safe Mode making its removal complicated. For this step, you require access to another computer.

To regain control of the files encrypted by Rokku, you can also try using a program called Shadow Explorer. More information on how to use this program is available here.

shadow explorer screenshot

 To protect your computer from file encrypting ransomware such as this, use reputable antivirus and anti-spyware programs. As an extra protection method, you can use programs called HitmanPro.Alert and Malwarebytes Anti-Ransomware, which artificially implant group policy objects into the registry to block rogue programs such as Rokku ransomware.

HitmanPro.Alert CryptoGuard - detects encryption of files and neutralises any attempts without need for user intervention:

hitmanproalert ransomware prevention application

Malwarebytes Anti-Ransomware Beta uses advanced proactive technology that monitors ransomware activity and terminates it immediately - before reaching users' files:

malwarebytes anti-ransomware

  • The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups. More information on online backup solutions and data recovery software Here.

Other tools known to remove Rokku ransomware:

About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

PCrisk security portal is brought by a company RCS LT. Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.

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Removal Instructions in other languages
Malware activity

Global malware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

QR Code
Rokku virus QR code
A QR code (Quick Response Code) is a machine-readable code which stores URLs and other information. This code can be read using a camera on a smartphone or a tablet. Scan this QR code to have an easy access removal guide of Rokku virus on your mobile device.
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