Kool Virus

7-day Free Trial w/Credit card, no charge upfront or if you cancel up to 2 days before expiration; Subscription price varies per region w/ auto renewal unless you timely cancel; notification before you are billed; 30-day money-back guarantee; Read full terms and more information about free remover.

*Kool is a variant of Stop/DJVU. Source of claim SH can remove it.

The Kool File

The Kool file stands out as a formidable threat in the modern ransomware landscape, leveraging state-of-the-art encryption algorithms to hold digital files hostage. Nestled within the cryptomalware family tree, it meticulously searches a computer system, hunting for the most valued file formats. Upon identification, it promptly wraps them in an intricate encryption layer. When users attempt to gain access, they’re greeted with a stern ransom note, effectively holding their data for ransom. The culprits behind the Kool file ransomware tantalize victims with the prospect of a decryption tool — but at a cost. And the stakes are high: failing to pay could mean irreversible data loss. In the ransomware’s eyes, every file type, be it personal or professional, is fair game, making the restoration process seem like a Herculean task.

Files encrypted by Kool virus ransomware (.kool extension)
Encrypted files by Kool virus ransomware

How to decrypt Kool ransomware files?

Decrypting the encryption imposed by the Kool ransomware is no walk in the park. Its encryption mechanisms are layered and sophisticated. Therefore, your task is to pinpoint the exact ransomware variant that has infiltrated your system. Armed with this information, you can then embark on a quest for the possible decryption tools tailored for that variant. A robust defense against ransomware is not just about recovery but prevention. Ensuring you have backups, installing the latest software patches, arming your system with a formidable antivirus, and resisting the cybercriminals’ allure of ransom — these steps form the bedrock of cybersecurity in the age of ransomware.

How to remove Kool ransomware virus and restore the files?

To remove the Kool ransomware effectively, you need a plan — and a meticulous one at that. The initial move is isolating the infected device, disconnecting it from networks to curb its spread. With the device isolated, deploy a reputable antivirus for a comprehensive scan that can detect and remove the malware’s files. If you were prudent enough to maintain backups, the road to recovery is clearer. However, in situations where decryption seems like chasing a mirage, turning to legal avenues becomes paramount. And remember, prevention is better than cure. Regular software updates and enhanced cyber vigilance can act as potent deterrents against the onslaught of future ransomware attacks.

The Kool virus

The Kool virus represents a new variant of ransomware, with a voracious appetite for data. Once inside a system, it sets its encryption code in action, holding files captive. At the end of its operation, victims are presented with a chilling ransom note. These malicious pieces of software often sneak into systems unnoticed, exploiting the slightest user interaction with their distribution sources. It’s essential to familiarize oneself with typical ransomware sources to avoid potential pitfalls. Ransomware strains like Kool, Nood, Wisz or Wiaw have a sinister modus operandi: they block critical system components, effectively taking them hostage, and then demand a ransom for their release. Dealing with these threats can be a nerve-wracking experience, especially when the options for mitigation are limited or, in some unfortunate cases, non-existent.

Kool virus ransomware text file (_readme.txt)
The Kool virus ransom note


Ransomware has evolved from a niche threat to a digital behemoth over the past two decades. Its rapid evolution makes it one of the most formidable cybersecurity challenges of our time. The archetypal ransomware modus operandi is straightforward yet devastating: it encrypts user files. Kool’s malicious clutches are nothing short of a nightmare for its victims. A common misconception is that paying the demanded ransom guarantees data retrieval. This couldn’t be further from the truth. Instead of funding these shadowy cyber entities, it’s prudent to harness insights from experts on ransomware mitigation and data recovery. Regular software patches, paired with robust security tools, act as the first line of defense against these digital marauders.


The .Kool ransomware epitomizes the menacing nature of modern malware. In a covert operation, it alters file structures, rendering them inaccessible. Only a unique decryption tool holds the promise of restoring everything back to normal. The creators of this ransomware demand a king’s ransom, often in the form of untraceable digital currency like bitcoins. However, paying doesn’t necessarily mean regaining access. Some of these new-age ransomware strains, .Kool included, employ encryption mechanisms so sophisticated that they outstrip the capabilities of many conventional defense tools. Staying ahead of these nefarious entities requires a multi-pronged approach: a fortified defense mechanism, staying abreast of emerging threats, and a robust backup strategy for crucial files.

Kool Extension

Ransomware is a multifaceted threat, branching into several sub-categories. The Kool extension falls in the file-encrypting sub-type, which is the most insidious one because when you become a victim of the malware, you are faced with a psychological game in which the cybercriminals are using fear as a weapon, demanding ransoms and toying with your desperation. The Kool extension seizes control of files, encrypting them with the complex chipher and even if you decide to fulfill the intimidating ransom demands, there’s no guarantee of data retrieval. Another sub-category is the Screen-locking Ransomware, which operates by locking screens on the infected devices and rendering them unusable. This sub-type does not tamper with the underlying files, but makes the screen inaccessible due to the ransom notification overlay.

Kool Ransomware

Kool ransomware is not just about locking up your computer files; it represents a bigger problem. It’s a malicious tool that takes advantage of how much we rely on digital data like photos, work, and personal information. It holds these things hostage, making us pay to get them back. What’s worse, when Kool ransomware gets into a computer, it often brings other harmful programs with it, including Spyware or Trojans. These pieces of malware can steal our personal information or spread to other computers, making the problem even bigger. It’s like a chain reaction, and it can put both people and companies in danger.

What is Kool File?

A Kool file is a digital file like a document or a picture that’s been locked up by the ransomware, which means you can’t open or use it unless you pay a ransom. Recovering an Kool files is usually done through a process called decryption, but sometimes it’s not possible if you don’t have the right key. To avoid this situation, it’s a good idea to regularly back up your important files. If your computer does get infected, you might also consider getting help from an expert, even though it can be costly, it’s better than paying a ransom to scammers. Another option is to search for solutions in online blogs and forums, where people share their experiences and knowledge.


Danger LevelHigh (Ransomware is by far the worst threat you can encounter)
Detection Tool

anti-malware offerOFFER Read more details in the first ad on this page, EULA, Privacy Policy, and full terms for Free Remover.

*Kool is a variant of Stop/DJVU. Source of claim SH can remove it.

Before you begin this guide

Make sure you take note of the following four points before starting the guide:

  • If there are external HDDs, USB sticks, tablets, phones, or other external devices with storage memory connected to your PC, unplug them immediately to prevent their files from getting encrypted as well.
  • Disconnect the computer from the web – this will ensure Kool doesn’t receive further instructions from its creators.
  • We advise against sending the requested ransom sum to the hackers but if you have nevertheless decided to o so, it’s recommended to not remove the Ransomware just yet and wait for after you’ve paid the ransom and hopefully received the decryption key.
  • Kool may seem to have automatically been removed from your computer, but even in such cases it’s still recommended completing the next steps.

Kool Ransomware Removal

To remove Kool and prevent the future encryption of more of your files, there are four main steps that you must perform:

  1. Find out if there’s a potentially rogue program on your computer that may be the cause of the Ransomware infection, and if there is, delete it.
  2. Make sure that there are no malware processes still running on your computer by using the Task Manager tool.
  3. Search the system for remaining malware files and delete anything harmful you may find.
  4. Clean the System Registry, as well as the Hosts file, and the Startup items list, to fully remove Kool.

For more details about each of those four steps, please, have a look at the instructions we’ve shared below.

Detailed removal instructions

Step 1

To look for potentially rogue programs, go to Start Menu > Control Panel > Uninstall a Program, where you will see what programs are on your computer and hopefully find the one that has caused the infection. Look through the entries in the list, and if you notice anything suspicious or unfamiliar that has been installed recently, select it, and then use the Uninstall button from the top to proceed to the uninstallation. Make sure that you disable any options in the uninstall are that would allow data related to the unwanted program to remain on the computer.

This image has an empty alt attribute; its file name is uninstall1.jpg

Step 2


*Kool is a variant of Stop/DJVU. Source of claim SH can remove it.

Search for the Task Manager tool using the search bar below the Start Menu or simply press Ctrl, Shift, and Esc. Next, open Processes from the top and look for unusually-named processes with excessive RAM memory and/or CPU use. To figure out if a given suspected process is harmful, do the following:

  • First, we suggest looking up the name of the process – if it is indeed related to any malware, there will probably be many posts on cybersecurity forums that talk about it and warn about its malicious nature.
  • The next thing you could do is go to the process’ File Location by right-clicking it in the Task Manager and selecting the first option from the menu. Then, using the scanner we’ve shared below, test each file in the Location folder to see any of them are malicious. Obviously, if anything gets flagged as malware, this would also mean that the process the file is related to is also malicious.
    Each file will be scanned with up to 64 antivirus programs to ensure maximum accuracy
    This scanner is free and will always remain free for our website's users.
    This file is not matched with any known malware in the database. You can either do a full real-time scan of the file or skip it to upload a new file. Doing a full scan with 64 antivirus programs can take up to 3-4 minutes per file.
    Drag and Drop File Here To Scan
    Drag and Drop File Here To Scan
    Analyzing 0 s
    Each file will be scanned with up to 64 antivirus programs to ensure maximum accuracy
      This scanner is based on VirusTotal's API. By submitting data to it, you agree to their Terms of Service and Privacy Policy, and to the sharing of your sample submission with the security community. Please do not submit files with personal information if you do not want them to be shared.
    This image has an empty alt attribute; its file name is task-manager1.jpg

    Processes that are detected as harmful must be ended and their file location folders must be deleted from the computer.

    This image has an empty alt attribute; its file name is task-manager2.jpg

    Step 3

    You need to ensure Kool is unable to start its processes again – do this by booting your computer into Safe Mode.

    Step 4

    *Kool is a variant of Stop/DJVU. Source of claim SH can remove it.

    Click the Start Menu, type Folder Options, press the Enter key, and click the View section in the newly-opened window. Then check the Show hidden files, folders, and drives setting, and click on OK.

    Next, copy-paste the first of the items listed below in the Start Menu, press Enter, and sort the files in the folder that opens by date. Delete everything that’s been created after Kool infected you, and then repeat the same process with the other folders. Only in the one named Temp you must delete all data and not only the most recent files.

    • %AppData%
    • %LocalAppData%
    • %ProgramData%
    • %WinDir%
    • %Temp%

    Step 5

    Press together Winkey and R and when the Run search box shows, type msconfig in it and press Enter. When taken to the System Configuration window, click Startup, search the list of items for ones with unknown manufacturers and/or ones you don’t recognize, disable those items and click OK.

    The next thing you have to do is go to the hard drive where your Windows is installed (on most PCs that would be the C: drive), and navigate to the Windows/System32/drivers/etc folder. Once there, double-click on the file named Hosts, then select Notepad when asked to pick a program, and when the file opens, look towards the end of the text to see if there are any strange IPs present there. If there are, copy-paste them down in the comments and we will soon tell you if anything needs to be done about them.

    This image has an empty alt attribute; its file name is hosts2.jpg

    Step 6

    Be very careful with this step and only delete items you are certain are related to Kool . Ask us in the comments if you are unsure about anything.

    Start the Registry Editor tool by typing regedit.exe in the Start Menu, clicking the first result, and then clicking Yes.

    In the Editor, press Ctrl + F, then type Kool , and hit Enter. Delete any item that gets found in the Registry, and repeat the search to look for more rogue Kool items and to delete them as well.

    This image has an empty alt attribute; its file name is 1-1.jpg

    After having deleted all Kool items from the Registry, navigate to the next three directories using the panel to the left and search them for suspicious keys (sub-folders). Tell us in the comments if you find anything with a strange name that seems to be randomly-generated, and we will tell you if it is something that must be eliminated.

    • HKEY_CURRENT_USER > Software
    • HKEY_CURRENT_USER > Software > Microsoft > Windows > CurrentVersion > Run
    • HKEY_CURRENT_USER > Software > Microsoft > Internet Explorer > Main

    If Kool is still in the system

    Ransomware infections are often facilitated by Rootkits, Trojans, or other secondary threats that make sure the Ransomware stays in the system in spite of the users’ attempts to delete it. If you haven’t been able to manually delete Kool , it’s possible that you are in such a situation and that there’s another malicious program on your PC.

    In this case, what we’d advise you to do is use a specialized anti-malware program that can take care of all threats that are on your computer at the same time. A powerful tool we can recommend in such scenarios can be found throughout the guide, so consider giving it a try.

    How to Decrypt Kool files

    After being affected by a ransomware, there are numerous tactics to consider for retrieving encrypted documents. Yet, the effectiveness of these methods isn’t guaranteed, given that the outcome hinges on the exact ransomware type compromising your files. Your primary step is pinpointing the ransomware variant, which can be discerned by observing the file extensions of your encrypted data.

    New Djvu Ransomware

    Recent iterations of Djvu ransomware bring forth the STOP Djvu version, identified by its .Kool file extension on encrypted data. When this ransomware uses an offline key for encryption, there’s potential for data recovery. A decryption instrument specifically designed for this variant is accessible via the link below.

    Decryption Tool for STOP Djvu

    Unlocking Files

    Begin by downloading the decryption software and launching it with administrator privileges. Before moving forward, acquaint yourself with the user terms and agreements on display. Hit the “Decrypt” button to commence the process.

    Kindly note that the tool might not be helpful on encryption using unregistered offline keys or online encryption techniques. For queries or feedback, feel free to use the comments section below this article.

    Caution! Prior to decrypting, it’s imperative to scan your PC for malevolent ransomware fragments and suspicious registry entries. The endorsed anti-malware application and the integrated online virus scanner on this site are helpful for purging ransomware-associated threats.


    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.

    Leave a Comment

    We are here to help! Use SpyHunter to remove malware in under 15 minutes.

    Not Your OS? Download for Windows® and Mac®.

    * See Free Trial offer details and alternative Free offer here.

    ** SpyHunter Pro receives additional removal definitions and manual fixes through its HelpDesk in cases where they are needed.

    Spyware Helpdesk 1