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Remove Kuub ransomware (Free Guide) - Decryption Methods Included

removal by Lucia Danes - - | Type: Ransomware

Kuub ransomware is the recent version of the notorious Djvu that comes from pirated software and cracks or game cheats

Kuub ransomware Kuub ransomware is the cryptovirus that aims to encrypt files and add custom file marker .kuub to all of the encoded data. This malware makes files unopenable and immediately after that, delivers a ransom note file with the cryptocurrency-extortion message. This is the version of Djvu ransomware that recently changed some features in coding and became more dangerous than before. Since criminals behind the virus are known from previous attacks, paying the ransom is not recommended by anyone.

All the known features of this particular threat remain unchanged for a while, so the only unique Kuub ransomware virus detail is .kuub file extension since the same contact emails got used for many previous variants. Also, the ransom amount with the half-off discount that is explained in a _readme.txt also – common for the family.

Questions about Kuub ransomware

This virus is freshly reported by users, so not many details can be revealed, all the claims are based on previous versions like Karl or Nesa. However, users reported that most of them got infected after downloading pirated content.[1] This was firstly discovered by a researcher Michael Gillespie, that previously managed a decryption tool capable of recovering victims' files.[2] After all those encryption changes back in August, the decrypter is no longer supported.

Name Kuub ransomware
Symptoms Malware gets on the machine and encrypts common files, marks them using .kuub file extension and demands ransom for alleged file recovery in the ransom note file _readme.txt that includes contact information and payment methods
Family Djvu/STOP virus
Contact information,
Possible decryption
  • When offline keys are in use for encryption, you can try the method listed here.
  • A tool from Dr.Web researchers can also be helpful.
Distribution Malicious files typically get added to emails with common company names or alleged financial information. According to a few samples and user reports, such malicious files get packed in software crack, game cheat code packages or other pirated files
Damage The virus can alter system settings, infect the system with other malware. Registry entry modification can make a huge difference in the performance of the infected computer. Programs and functions get disabled to interfere with the file recovery and malware termination
Elimination Kuub ransomware removal should be performed using anti-malware tool or a professional program designed to clean such devices like Reimage

Kuub ransomware is the infection that blocks users' files and replaces the original code, so decryption can be the only solution for those files. Unfortunately, this ransomware family is known for being persistent and dangerous, all the claims about the decryption tool might be not true.

Even the test decryption that is typically offered on the ransom note is mainly for building trust between criminals and victims. Kuub ransomware can store some of the files before encoding them and then send you copied versions instead of recovering the existing file. This is one of 170 versions, so stay away from the crooks and get rid of the threat completely with an anti-malware tool.

You should go straight to Kuub ransomware removal, but before you delete every part of the virus, you should store encrypted files and copies of malware associated data if you want to recover those archives, documents or photos using decryption services later on.

Unfortunately, besides encryption process Kuub ransomware virus also can:

  • create mutexes;
  • modify registry;
  • obtain information from your computer or even the browser directly;
  • plant files or programs on the system;
  • damage system files.

To ensure that victims cannot access particular sites Kuub ransomware leaves a modified host file placed in C:\Windows\System32\drivers\etc\. Make sure to find it and delete it. If you leave it on the machine, the infection may repeat itself again.

Kuub ransomware virus
Kuub ransomware is the malware that can be easily indicated by a .kuub file marker and _readme.txt ransom note file.
When developers started to use proper asymmetric encryption method, the decryption tool that officially was developed for the STOP virus, but worked great for many Djvu versions got disabled. Kuub ransomware removal is possible with anti-malware tools, but victims then leave with encrypted files. Fortunately, these sites can provide you the initial information about decryptors:

You should firstly check these databases and then forus on processes and solutions that help remove Kuub ransomware. The proper method involves professional anti-malware programs and full system scans, but such a technique is not recovering your encrypted files. Although tools like Reimage can repair virus damage on the machine.

For that, you should either look for third-party decryption software or data restoring applications and then restore Kuub ransomware affected files. Of course, the best solution is to restore data from external backups, but not all people tend to make them occasionally. Other options that may help are listed below the virus removal guides. Kuub files virus
Kuub cryptovirus is the one that comes silently and only reveals itself after file encoding process.

Stay away from questionable sources and torrent files

You should be familiar with the typical ransomware distribution methods that involve malicious spam attachments and other malware that drops cryptovirus as a secondary payload. However, criminals tend to change their tactics and mix them up to spread on a global scale across the world.

With as little information that we have, it is confirmed that this Djvu version uses the common method used by these developers – cracks and pirated files. Users say that infection appeared immediately after downloading the cracked software, game cheat code or a different file from the torrent site. 

Experts[3] always note that any free download page can put you at risk since sources are never reliable or known. Also, the same goes for emails with attached files since malicious macros get embedded in executables or documents posing as financial information. All these instances can be avoided when you pay attention to processes happening and sources you rely on.

Get rid of the damage and eliminate Kuub ransomware with an AV tool

The faster results of Kuub ransomware removal can be achieved when you use anti-malware tools which have been developed with a purpose to help you with such malware. Although these programs are not capable of recovering encoded files, Reimage, SpyHunter 5Combo Cleaner, or Malwarebytes can repair virus damage and sometimes repair settings of the system.

However, you need to remove Kuub ransomware fully from the device if you want to get back to a completely safe system and continue to work with the computer as before. You may lose your files permanently and spend your money for no reason if decided to pay.

This is why we recommend getting proper tools and eliminating this Kuub ransomware virus. This is especially useful when you deal with such a notorious malware family. Rely on tips below and double-check before adding file backups on the machine.

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What to do if failed?
If you failed to remove virus damage using Reimage, submit a question to our support team and provide as much details as possible.
Reimage is recommended to remove virus damage. Free scanner allows you to check whether your PC is infected or not. If you need to remove malware, you have to purchase the licensed version of Reimage malware removal tool.
Alternative Software
Different security software includes different virus database. If you didn’t succeed in finding malware with Reimage, try running alternative scan with SpyHunter 5.
Alternative Software
Different security software includes different virus database. If you didn’t succeed in finding malware with Reimage, try running alternative scan with Combo Cleaner.

To remove Kuub virus, follow these steps:

Remove Kuub using Safe Mode with Networking

Reboot the system in Safe Mode with Networking and then eliminate the threat using the AV tool. This way you can achieve much better Kuub ransomware removal results

  • Step 1: Reboot your computer to Safe Mode with Networking

    Windows 7 / Vista / XP
    1. Click Start Shutdown Restart OK.
    2. When your computer becomes active, start pressing F8 multiple times until you see the Advanced Boot Options window.
    3. Select Safe Mode with Networking from the list Select 'Safe Mode with Networking'

    Windows 10 / Windows 8
    1. Press the Power button at the Windows login screen. Now press and hold Shift, which is on your keyboard, and click Restart..
    2. Now select Troubleshoot Advanced options Startup Settings and finally press Restart.
    3. Once your computer becomes active, select Enable Safe Mode with Networking in Startup Settings window. Select 'Enable Safe Mode with Networking'
  • Step 2: Remove Kuub

    Log in to your infected account and start the browser. Download Reimage or other legitimate anti-spyware program. Update it before a full system scan and remove malicious files that belong to your ransomware and complete Kuub removal.

If your ransomware is blocking Safe Mode with Networking, try further method.

Remove Kuub using System Restore

System Restore is the feature that can also make your life easier. You can recover the system to a previous point before Kuub ransomware infection

  • Step 1: Reboot your computer to Safe Mode with Command Prompt

    Windows 7 / Vista / XP
    1. Click Start Shutdown Restart OK.
    2. When your computer becomes active, start pressing F8 multiple times until you see the Advanced Boot Options window.
    3. Select Command Prompt from the list Select 'Safe Mode with Command Prompt'

    Windows 10 / Windows 8
    1. Press the Power button at the Windows login screen. Now press and hold Shift, which is on your keyboard, and click Restart..
    2. Now select Troubleshoot Advanced options Startup Settings and finally press Restart.
    3. Once your computer becomes active, select Enable Safe Mode with Command Prompt in Startup Settings window. Select 'Enable Safe Mode with Command Prompt'
  • Step 2: Restore your system files and settings
    1. Once the Command Prompt window shows up, enter cd restore and click Enter. Enter 'cd restore' without quotes and press 'Enter'
    2. Now type rstrui.exe and press Enter again.. Enter 'rstrui.exe' without quotes and press 'Enter'
    3. When a new window shows up, click Next and select your restore point that is prior the infiltration of Kuub. After doing that, click Next. When 'System Restore' window shows up, select 'Next' Select your restore point and click 'Next'
    4. Now click Yes to start system restore. Click 'Yes' and start system restore
    Once you restore your system to a previous date, download and scan your computer with Reimage and make sure that Kuub removal is performed successfully.

Bonus: Recover your data

Guide which is presented above is supposed to help you remove Kuub from your computer. To recover your encrypted files, we recommend using a detailed guide prepared by security experts.

If your files are encrypted by Kuub, you can use several methods to restore them:

Data Recovery Pro is a file restoring program that should help with encrypted or deleted data

Restore files affected by Kuub ransomware with this program or data that got accidentally deleted

  • Download Data Recovery Pro;
  • Follow the steps of Data Recovery Setup and install the program on your computer;
  • Launch it and scan your computer for files encrypted by Kuub ransomware;
  • Restore them.

Windows Previous Versions also is the system feature helpful with encoded files

When you employed System Restore, Kuub ransomware encrypted data can be recovered with the help of this feature

  • Find an encrypted file you need to restore and right-click on it;
  • Select “Properties” and go to “Previous versions” tab;
  • Here, check each of available copies of the file in “Folder versions”. You should select the version you want to recover and click “Restore”.

ShadowExplorer is the alternative for databackups

When you are sure that your Shadow Volume Copies got deleted by Kuub ransomware, ShadowExplorer is not going to help. If not, try to recover data using this feature

  • Download Shadow Explorer (;
  • Follow a Shadow Explorer Setup Wizard and install this application on your computer;
  • Launch the program and go through the drop down menu on the top left corner to select the disk of your encrypted data. Check what folders are there;
  • Right-click on the folder you want to restore and select “Export”. You can also select where you want it to be stored.

Decryption tool for the particular Kuub ransomware is not released yet

Finally, you should always think about the protection of crypto-ransomwares. In order to protect your computer from Kuub and other ransomwares, use a reputable anti-spyware, such as Reimage, SpyHunter 5Combo Cleaner or Malwarebytes

About the author

Lucia Danes
Lucia Danes - Virus researcher

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