Remove KOOL Ransomware Virus (+DECRYPT .kool Files)

Kool virus – what is it?

Kool ransomware can correctly be described as a STOP/Djvu malware family. That type of virus is targeted at single users. This specification supposes that Kool does not bring any sort of additional malware, which usually helps malware of other families to control your computer. Because the majority of people do not have anything valuable on their PCs, there is no reason to infiltrate other viruses that increase the risk of failure of the whole ransomware operation.

The typical signs of this ransomware activity is the emersion of .kool files in your folders, instead of the files you used to have. The photo.jpg turns into photo.jpg.kool, report.xlsx – into report.xlsx.kool and so on. You are not able to stop this process, and can’t open those documents – they are encrypted with quite a strong algorithm.

You can also see different other signs of ransomware activity. Abruptly stopped Microsoft Defender and inability to check the well-known anti-malware forums or web pages, where the removal and file decryption guides are posted. You will see how it works in the paragraph below. The removal and decryption guide are also available – check below how to remove the Kool virus and get the .kool files back.

How did Kool ransomware encrypt my files?

After the malware injection, the Kool virus starts a connection with its command and control server. This server is commanded by malware maintainers – crooks who manage the spreading of this malware. Another activity which is done by those crooks is answering the email messages of sufferers, who intend to decrypt their files.

The files are ciphered with one of the strongest encryption algorithm – AES-256. The digit in the name of this algorithms means the power of two – 2^256 for this case. 78-digit number of possible decryption keys variations – it is impossible to brute force it. As analysts say, it will take more time than the Earth can estimate to exist, even if you use the most powerful computers. In each folder that contains the encrypted documents, Kool virus leaves the _readme.txt file with the following contents:

ATTENTION!

Don't worry, you can return all your files!
All your files like pictures, databases, documents and other important are encrypted with strongest encryption and unique key.
The only method of recovering files is to purchase decrypt tool and unique key for you.
This software will decrypt all your encrypted files.
What guarantees you have?
You can send one of your encrypted file from your PC and we decrypt it for free.
But we can decrypt only 1 file for free. File must not contain valuable information.
Do not ask assistants from youtube and recovery data sites for help in recovering your data.
They can use your free decryption quota and scam you.
Our contact is emails in this text document only.
You can get and look video overview decrypt tool:
https://wetransfer.com/downloads/a832401adcd58098c699f768ffea4f1720240305114308/7e601a
Price of private key and decrypt software is $999.
Discount 50% available if you contact us first 72 hours, that's price for you is $499.
Please note that you'll never restore your data without payment.
Check your e-mail "Spam" or "Junk" folder if you don't get answer more than 6 hours.


To get this software you need write on our e-mail:
support@freshingmail.top

Reserve e-mail address to contact us:
datarestorehelpyou@airmail.cc

Your personal ID:
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Nonetheless, you can still run some of your documents. The Kool ransomware encrypts only the first 150 KB of each file, but the other piece of this document can be opened. Primarily, it works best with audio/video files, which are surely larger than 150 kilobytes. Not each media player is able to open these files – WinAmp is the best option, since it is free and well-tested. First seconds of every file will be missing – this part is encrypted – but the rest of the document will be accessible like nothing happened.

Is Kool ransomware dangerous for my PC?

As it was described several paragraphs before, ransomware is not only about encrypting the files. Kool malware makes the changes in your operating system in order to prevent looking for the virus removal and file decryption guides. Malware does not establish the software barrier – it just alters the system settings, primarily – networking and security configurations.

Through the networking configurations, the most changed item is the HOSTS file. This text file keeps the DNS-address configurations, which are used by the web browsers while requesting to the server. If you add a specific DNS-address for the certain website, your web browser will connect that website through that DNS next time. Ransomware alters this file, adding the non-existent DNS, so any of the web browsers will show you the “Unable to resolve the DNS-address” error.

Other alterations done by the ransomware are aimed at prevention of operative spotting of itself, and also disabling the installation of the majority of security tools. Kool virus implements several modifications in Group Policies – the system configuration app which gives you the right to alter the abilities of each program. In such a way, ransomware disables the Microsoft Defender and various other anti-malware apps, and also disables the launch of antivirus installation files.

How did I get infected?

Throughout the whole term while STOP/Djvu family is active, it was using questionable software as the main method of ransomware injection. Under the term of questionable programs I mean software that are already not supported by the maintainer and distributed through the file sharing websites. These applications may be hacked, to make them usable without buying any license. Another example of such a program type is different hacking tools – cheat engines, keygens, Windows activation tools and so on.

Such programs may be distributed in different ways – through the website that offers a downloading link, or through the peering networks – ThePirateBay, eMule and so on. All these sources are known as the most popular computer piracy resources. People use these sites to get a wide range of apps or games for free, even if these programs must be purchased. Nobody can prevent the users who hack these apps from adding viruses of some type to the files of the hacked app. Hacktools, meanwhile, are created for outlaw actions, so their creators may easily embed the ransomware under the guise of some program element.

These hacked programs, regardless of their source, are one of the most often sources for various viruses, and definitely the most popular one for Kool malware. It is better to stop using of it, and not only because of virus spreading risks. Avoiding the license buying is an outlaw action, and both hackers and folks who use hacked programs fall under the charge of piracy.

How do I remove Kool ransomware?

The Kool ransomware is pretty hard to wipe out manually. Really, because of the amount of changes it makes into your PC, it is almost impossible to find them all and repair. The best option is to use anti-malware programs. But which one to choose?

You may see the advices to use Microsoft Defender, which is already in your system. Nonetheless, as it was mentioned before, most of STOP/Djvu virus examples disable it even before the encryption process. Using the third-party application is the only possible option – and I can advice you the GridinSoft Anti-Malware as a solution for this case. It has perfect detection abilities, so the Kool ransomware will not be missed. It is also capable of system recovery, which is heavily needed after the Kool virus attack.

To remove Kool malware infections, scan your computer with legitimate antivirus software.

After the ransomware removal, you can go to file decryption. Ransomware removal is needed to prevent the repeating ciphering of your files: while Kool ransomware is active, it will not miss any unencrypted file.

How to decrypt the .kool files?

There are two ways to decrypt your files after a Kool ransomware attack. First one and the most popular is file decryption. It is conducted with a special tool, designed by Emsisoft, and named Emsisoft Decryptor for STOP/Djvu. This program is absolutely free. Analysts update its decryption keys databases as often as possible, so you will definitely get your files back, sooner or later.

Another way to get your files back is to try to recover them from your disk drives. Since Kool virus deletes them and substitutes with a ciphered copy, the residue of the documents are still kept on the disk drive. After the removal, the information about them is removed from the file system, but not from a disk drive. Special apps, like PhotoRec, are able to recover these files. It is free, too, and may also be used for file recovery in case when you have deleted something unintentionally.

Decrypting the .kool files with Emsisoft Decrypter for STOP/Djvu

Download and install Emsisoft Decrypter tool. Agree with its EULA and continue to the interface.

The interface of this program is extremely easy. All you have to do is to select the folder where the encrypted files are stored, and wait. If the program has the decryption key which corresponds to your ransomware case – it will decrypt it.

During the use of Emsisoft Decrypter for STOP/Djvu, you may observe various error messages. Don’t worry, that does not mean that you did something wrong or a program does not work properly. Each of these errors refer to a specific case. Here is the explanation:

Error: Unable to decrypt file with ID: [your ID]

The program does not have a corresponding key for your case. You need to wait for some time until the key database will be updated.

No key for new variant online ID: [your ID]

Notice: this ID appears to be an online ID, decryption is impossible.

This error means that your files are encrypted with an online key. In such a case, the decryption key is unique and stored on the remote server, controlled by crooks. Unfortunately, the decryption is impossible.

Result: No key for new variant offline ID: [example ID]

This ID appears to be an offline ID. Decryption may be possible in the future.

Ransomware uses the offline key to encrypt your files. This key is not unique, so you likely have it in common with another victim. Since offline keys must be collected, too, it is important to keep calm and wait until the analysts team finds one which will fit your case.

Remote name could not be resolved

This error indicates that the program has problems with DNS on your computer. That’s a clear sign of malicious alterations in your HOSTS file. Reset it using the official Microsoft guide.

Recovering the .kool files with PhotoRec tool

PhotoRec is an open-source tool, which is designed to recover the deleted or lost files from the disk. It checks each disk sector for the residues of deleted files, and then tries to recover them. That app is able to recover the files of more than 400 different extensions. Because of the described feature of ransomware encryption mechanism, it is possible to use this tool to get the original, unencrypted files back.

Download PhotoRec from the official website. It is absolutely free, however, its developer warns that he does not guarantee that this program will be 100% effective for file recovery purposes. Moreover, even paid apps can barely give you such a guarantee, because of the chain of random factors that can make the file recovery harder.

Unzip the downloaded archive to the folder you like. Don’t worry because of its name – TestDisk – this is the name of the utility developed by the same company. They decided to spread it together since PhotoRec and TestDisk are often used together. Among the unzipped files, search for qphotorec_win.exe file. Run this executable file.

Before you can start the recovery process, you need to specify several settings. In the drop-down list, choose the logic disk where the files were stored before the encryption.

Then, you need to specify the file formats you need to recover. It may be difficult to scroll all 400+ formats, luckily, they are sorted by alphabetical order.

Finally, name the folder you want to use as a container for recovered files. The program will likely dig out a lot of useless files, which were deleted intentionally, so desktop is a bad solution. The best option is to use the USB-drive.

After these easy manipulations, you may just press the “Search” button (it turns active if you specified all required parameters). The recovery process may take several hours, so keep patient. It is recommended not to use the computer during this term, since you may overwrite some files you are intending to recover.

Frequently Asked Questions