Remove COOL Ransomware Virus (+DECRYPT .cool Files)

Cool ransomware is a sort of computer virus that infiltrates your computer, encrypts your documents, and then asks to pay the ransom for file decryption. Besides these unpleasant actions, that virus also alters some important settings and can even stop your antivirus program.

Cool Ransomware Summary

NameCool virus
TypeSTOP/Djvu Ransomware
DamageAll files are encrypted and cannot be opened without paying a ransom. Additional password-stealing trojans and malware infections can be installed together with a ransomware infection.
Cool Removal Tool To use full-featured product, you have to purchase a license. 6 days free trial available.

Cool malware – what is it?

Cool ransomware can correctly be classified as a STOP/Djvu virus family. That type of computer virus is aimed on single users. This feature supposes that Cool does not carry any type of additional viruses, which often helps malware of other families to control your computer. Because of the fact that the majority users do not have anything valuable on their PCs, there is no reason to infiltrate other malware that increases the risk of failure of the whole ransomware operation.

The usual signs of Cool virus activity is the appearance of .cool files in your folders, instead of the document you used to have. The photo.jpg turns into, report.xlsx – into and so on. You are not able to stop this operation, as well as can’t open that files – they are ciphered with quite strong cipher.

Cool Virus - encrypted .cool files
Cool Encrypted Files

You can also spectate different other signs of ransomware activity. Abruptly stopped Microsoft Defender and inability to open the famous anti-malware forums or websites, where the ransomware removal and decryption guides are posted. You will see how it works in the paragraph below. The removal and decryption guide are also available – read below how to wipe out Cool ransomware and get the .cool files back.

How did Cool ransomware encrypt my files?

After the injection, the Cool virus starts a connection with its command and control server. This server is controlled by malware maintainers – crooks who manage the distribution of this ransomware. Another activity which is conducted by those crooks is answering the email messages of sufferers, who intend to get their files back.

The documents are encrypted 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 not real to brute force it. As analysts say, it will take more time than the Earth can approximately exist, even in case if you make use of the most powerful computers. In each folder that contains the encrypted file(s), Cool ransomware leaves the _readme.txt file with the following contents:


Don't worry, you can return all your files!

All your files like photos, 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.

You can get and look video overview decrypt tool:

Price of private key and decrypt software is $980.
Discount 50% available if you contact us first 72 hours, that's price for you is $490.

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:

Reserve e-mail address to contact us:

Your personal ID:

However, you can still use some of your documents. The Cool malware ciphers only the initial 150 KB of each file, but the rest of this file can be accessed. Primarily, it works best with audio/video files, which are definitely bigger than 150 kilobytes. Not every media player is capable of open these files – WinAmp is the best option, since it is free and well-tested. First seconds of each song or video will be silent – this part is encrypted – but the rest of the video or music will be accessible like nothing happened.

Is Cool ransomware dangerous for my PC?

As it was mentioned several paragraphs before, ransomware is not only about ciphering the files. Cool ransomware makes the changes in your system in order to prevent searching the malware removal and file decryption guides. Cool virus does not create the software obstacle – it just alters the settings, primarily – networking and security configurations.

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

Error 404

Other modifications done by the virus are targeted on prevention of early detection of itself, and also blocking the installation of the majority of security tools. Cool ransomware makes some changes in Group Policies – the system setting interface which gives you the right to change the rights of each program. In such a way, ransomware blocks the Microsoft Defender and various other security programs, as well as blocks the launch of anti-malware installation files.

How did I get infected?

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

This kind of applications may be spread in different methods – through the site that offers a downloading link, or through the peering networks – ThePirateBay, eMule and so on. All these sources are well-known as the biggest computer piracy resources. People use these pages to get different apps or games for free, even if these apps must be purchased. Nobody can stop the users who hack these apps from adding malware of some type to the files of the hacked tool. Hacktools, meanwhile, are created for outlaw targets, so their creators can easily add the virus under the guise of some program element.

injecting viruses into program
when adding the jumps on license checking, crackers can easily inject malicious code into the program

These hacked apps, regardless of their source, are one of the most often carriers for various malware, and definitely the most widespread one for Cool virus. It is better to stop making use of it, and not only because of virus injection risks. Avoiding the license purchase is an illegal action, and both hackers and persons who make use of cracked apps fall under the charge of piracy.

How do I remove Cool virus?

The Cool virus is extremely hard to delete manually. In fact, because of the number of alterations it makes in your PC, it is almost unreal to find them all and fix. The best option is to use antivirus programs. But which one to choose?

You can see the advices to use Microsoft Defender, which is already in your Windows. However, as it was mentioned earlier, the majority of STOP/Djvu malware examples block it even before the ciphering process. Using the third-party tool is the only possible solution – and I can advice you the GridinSoft Anti-Malware as a solution for this case. It has impressive detection abilities, so the Cool ransomware will not be missed. It is also capable of system repairing, that is heavily demanded after the Cool virus attack.

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

  • Download and install GridinSoft Anti-Malware by the button above. After the installation process, you will be offered to start a 6-day free trial. During this term, the security tool has its full functionality, so you will definitely be able to both wipe out the virus and fix your computer. To activate a trial period, you just need to type your email address.
  • Free trial activation GridinSoft Anti-Malware

  • After activating the trial, launch the full scan of your system. It will last for about 15-20 minutes, and check each folder you have in your system. Ransomware will not hide!
  • Full scan in GridinSoft Anti-Malware

  • When the scan is over, press the Clean Now button to wipe out the Cool ransomware and all other malware detected by a program.
  • Clean the viruses

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

    How to decrypt the .cool files?

    There are two ways to recover your files after a Cool virus attack. First one and the most obvious 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 surely get your files back, sooner or later.

    Another option to get your documents and photos back is to try to recover them from your disks. Since ransomware deletes them and substitutes with a ciphered copy, the residue of the documents are still kept on the disk. After the deletion, 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 a thing unintentionally.

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

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

    Emsisoft Decrypter EULA

    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.

    Emsisoft Decrypter decryption process

    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 .cool files with PhotoRec tool

    PhotoRec is an open-source tool, which is created to recover the deleted or lost files from the disk drive. It checks each disk sector for the residues of deleted files, and then attempts to recover them. That app is able to recover the files of more than 400 different formats. 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.

    PhotoRec and TestDisk

    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.

    PhotoRec recovering choose disk drive

    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.

    PhotoRec file formats

    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.

    PhotoRec recovery 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

    ✔️Are the files encrypted by Cool malware dangerous?

    No. Cool files is not a virus, it is not able to inject its code into the files and force them to execute it. The .EXT files are just the same as regular ones, but encrypted and cannot be opened in the usual way. You may store it together with normal files without any fears.

    ✔️Is it possible that antivirus software will delete the encrypted files?

    As I have mentioned in a previous paragraph, encrypted files are not dangerous. Hence, good anti-malware programs like GridinSoft Anti-Malware will not trigger on them. Meanwhile, some of the “disk cleaning tools” may remove them, stating that they belong to the unknown format and are likely broken.

    ✔️The Emsisoft tool says my files are encrypted with the online key and cannot be decrypted. What do I need to do?

    It is very unpleasant to hear that the files you have are likely lost. Ransomware creators lie a lot in order to scare their victims, but they tell the truth in claims about the strength of the encryption. Your decryption key is stored on their servers, and it is impossible to select it because of the strength of the encryption mechanism.

    Try other recovery methods – through the PhotoRec, or using the previously created backups. Search for the previous versions of these files – getting back a part of your dissertation, for example, is better than missing it all.

    Last option is just waiting. When the cyber police caughts the crooks who create and distribute ransomware, first get the decryption keys and publish it. Emsisoft analysts will surely take these keys and add them to the Decryptor databases. In some cases, ransomware creators may publish the rest of the keys when they stop their activity.

    ✔️Not all of my .cool files are decrypted. What do I need to do?

    The situation when the Emsisoft Decryptor failed to decrypt several files usually happens when you have not added the correct file pair for the certain file format. Another case when this problem may appear is when some problem occurred during the decryption process – for example, RAM limit reached. Try to perform the decryption process once again.

    Another situation when the Decryptor app may leave your files unencrypted is when ransomware uses different keys for certain files. For example, it may use offline keys for a short period of time when it has connection issues. The Emsisoft tool is not able to check both key types simultaneously, so you need to launch the decryption again, in order to repeat the process.

    Helga Smith

    I was always interested in computer sciences, especially data security and the theme, which is called nowadays "data science", since my early teens. Before coming into the Virus Removal team as Editor-in-chief, I worked as a cybersecurity expert in several companies, including one of Amazon's contractors. Another experience: I have got is teaching in Arden and Reading universities.

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