Kook Virus


.Kook is a malicious computer program used as a blackmailing tool that is able to block access to important user data. .Kook launches a data encryption process the moment it enters the system and usually shows no symptoms while encrypting the targeted files.

Kook Virus

The .Kook Virus will leave a .txt file with instructions for the ransom

Upon finishing the file-locking process, the virus informs its victims about the situation they are in by generating a big banner that contains a ransom message alongside instructions on how to carry out the payment. Since oftentimes the ransom payments required by Ransomware viruses are demanded in the Bitcoin currency, there will also likely be instructions on how to first buy Bitcoins so that you can pay the ransom with them. In some cases, it is possible that, instead of a banner, the ransom message is presented to the user in the form of a notepad file placed on the computer’s Desktop or inside the folders that contain the encrypted data.

According to the message once the user pays the specified sum by strictly following the hackers’ instructions a unique decryption key would be sent to them, which key would allow the user to regain their access to the locked files. Obviously, the whole purpose of the virus is to make you pay for that key. This, however, doesn’t mean that, after you pay, you would receive the promised key. The hackers behind .Kook, .Erif, .Kuus care about the money they are supposed to receive from their victims and not about whether or not the victims eventually manage to recover their data. Therefore, our suggestion for you is to avoid paying the ransom unless you really have no other choice.

The .Kook virus

The .Kook virus is a Ransomware variant that uses a new type of data encryption to make its victim’s files inaccessible. The .Kook virus can be removed but even after its removal, the files it has encrypted will continue to be unavailable.

Kook Virus

The .Kook Virus will encrypt your files

This is one of the main issues that users face when they get hit by this type of Ransomware threat. Getting the virus removed is still essential because it would prevent it from locking up any new files in the future. However, to restore your current data, removing .Kook would likely not be enough.

The .Kook file decryption

The .Kook file decryption is only possible through the use of the matching decryption key that the virus has generated for the specific computer. The .Kook file decryption cannot be completed using a key received by another victim of this Ransomware.

However, in some cases, you may not need to obtain the decryption key whatsoever. In our guide, right after the .Kook removal instructions (which we strongly advise you to complete), you will find linked several file-recovery methods that can be used to potentially restore the encrypted data without having the matching access key. Unfortunately, due to the advanced nature of viruses like .Kook, we cannot promise that these methods will work. Still, you won’t know until you try, so it is recommended that you first opt for these alternatives instead of going directly for the ransom payment.


Name .Kook
Type Ransomware
Danger Level High (Ransomware is by far the worst threat you can encounter)
Symptoms It is nearly impossible to notice Ransomware before it locks up your files because of an overall lack of visible symptoms.
Distribution Method Fake social media and email messages, pirated software, Trojan backdoors, and more.
Data Recovery Tool Not Available
Detection Tool

Remove .Kook Ransomware

Kook Virus

Some of the steps will likely require you to exit the page. Bookmark it for later reference.

Reboot in Safe Mode (use this guide if you don’t know how to do it).

Kook Virus


Press CTRL + SHIFT + ESC at the same time and go to the Processes Tab. Try to determine which processes are dangerous. 

Kook Virus

Right click on each of them and select Open File Location. Then scan the files with our free online virus scanner:

Kook Virus
Drag and Drop Files Here to Scan
Maximum file size: 128MB.

This scanner is free and will always remain free for our website's users. You can find its full-page version at: https://howtoremove.guide/online-virus-scanner/

Scan Results

Virus Scanner Result
Kook VirusClamAV
Kook VirusAVG AV
Kook VirusMaldet

After you open their folder, end the processes that are infected, then delete their folders. 

Note: If you are sure something is part of the infection – delete it, even if the scanner doesn’t flag it. No anti-virus program can detect all infections.

Kook Virus

Hold the Start Key and R –  copy + paste the following and click OK:

notepad %windir%/system32/Drivers/etc/hosts

A new file will open. If you are hacked, there will be a bunch of other IPs connected to you at the bottom. Look at the image below:

Kook Virus

If there are suspicious IPs below “Localhost” – write to us in the comments.

Type msconfig in the search field and hit enter. A window will pop-up:

Kook Virus

Go in Startup —> Uncheck entries that have “Unknown” as Manufacturer.

  • Please note that ransomware may even include a fake Manufacturer name to its process. Make sure you check out every process here is legitimate.

Kook Virus

Type Regedit in the windows search field and press EnterOnce inside, press CTRL and F together and type the virus’s Name. 

Search for the ransomware  in your registries and delete the entries. Be extremely careful –  you can damage your system if you delete entries not related to the ransomware.

Type each of the following in the Windows Search Field:

  1. %AppData%
  2. %LocalAppData%
  3. %ProgramData%
  4. %WinDir%
  5. %Temp%

Delete everything in Temp. The rest just check out for anything recently added. Remember to leave us a comment if you run into any trouble!

Kook Virus 

How to Decrypt .Kook files

We have a comprehensive (and daily updated) guide on how to decrypt your files. Check it out here.

If the guide doesn’t help, download the anti-virus program we recommended or try our free online virus scanner. Also, you can always ask us in the comments for help!


About the author


Brandon Skies

Brandon is a researcher and content creator in the fields of cyber-security and virtual privacy. Years of experience enable him to provide readers with important information and adequate solutions for the latest software and malware problems.

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