Kolz Virus Removal Guide (+Decrypt .kolz files)

Kolz Virus Ransomware

Kolz is a malicious software application functioning as typical ransomware. Michael Gillespie, the popular virus researcher, very first found this new name in the DJVU ransomware family.

Kolz was developed for the sole purpose to encrypt all popular file types. Realistically, as quickly as the encryption is successfully accomplished, the users are unable to get access to them. Kolz virus adds its own “.kolz” to all the encrypted files. For instance, the file “price_list.xls”, as soon as crypted by Kolz, will be titled as “price_list.xls.kolz”. As soon as the encryption is achieved, Kolz puts its own distinct text document (_readme.txt) into all the folders that store the encrypted files.

The alert mentioned by _readme.txt requesting the random os very similar to the alerts offered by other ransomware threats coming from the DJVU family. The caution basically shows that the data has been encrypted and the only service to get access to it is to use an unique standalone key. Regretfully, this declaration is absolutely true.

The method to encrypt the files utilized by Kolz is not entirely researched. However, there is no doubt that each computer system owner might be provided a special decryption key, which is absolutely special. It is very hard to recover the data without the proper type in place.

“Don’t worry, you can return all your files!”, from _readme.txt message:

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

One more peculiarity of the Kolz ransomware is that the users are not able to get access to the key. The decrypting key is hosted on a special server under the complete control by the scoundrels who have actually released the Kolz ransomware into the world wide web. In order to acquire the key and bring back the crucial information, the users are informed to contact the scams by means of email or by telegram and to pay the ransom in the quantity of $980.

The message likewise says that individuals should call the Kolz authors within 72 hours upon the moment of the data file encryption. The alert suggests that by doing so individuals will get a 50% discount rate, for that reason, the ransom amount falls to $490.

No matter what the amount of the ransom is, we strongly recommend that you do not pay the ransom. There is no warranty that these online criminals will keep their pledges, so they might not care at all what the victims feel about the file encryption, even when the amount of the ransom is gotten into their accounts. Thus, paying ransom often does not result in an effective recovery. So, the users may simply lose their money for nothing.

Similarly, we urge you not to get in touch with the scams as they advise. Do not move money into their wallets. There are no applications that might crack the Kolz virus or restore the information at no cost. For that reason, the only appropriate decision is to restore the data from possible backups (if offered).

Virus Summary

NameKolz Ransomware
File Extensionkolz
Short DescriptionThe ransomware encrypts all the data stored on your system and requires a ransom to be paid on your part supposedly to recover your important files.
SymptomsFile encryption by the ransomware is performed by means of the AES-256 algorithm (CFB mode) encryption algorithm. Once the encryption is completed, the ransomware adds its special .kolz extension to all the files modified by it.
Distribution MethodAdware bundles and software cracks
Similar InfectionsNpph, Ogdo, Kasp
Kolz Removal Tool   GridinSoft Anti-Malware
Kolz Decryption Tool   Emsisoft Djvu Decryptor

Do not forget that the Internet is now loaded with infections comparable to the Kolz virus. For example, this specific danger is generally similar to Brusaf and other ransomware-type infections. These damaging utilities have been developed in order to encrypt the important data and express the need for the users to pay the ransom. All these infections use the identical algorithm to produce the particular key for successful information decryption.

Unless the Kolz ransomware is still under the advancement process or has got some concealed bugs, it is not possible to bring back the information manually. Therefore, the only working option to avoid the loss of your essential data is to regularly keep current backups of all your vital files.

Another important piece of recommendations is to store the backups on special storage not linked to your main device. For instance, you might save it on the USB Flash Drive, or some external hard disk, or by using the cloud data storage services. Keeping the backups on your routine drive is really risky, because the backup may also be secured by the Kolz ransomware.

Leaks for the Kolz ransomware attack.

Kolz utilizes numerous courses to penetrate the vulnerable computer systems. It is not certain what specific approach was utilized in your case, nevertheless, the invasion may happen via the following channels:

  • bundling with third-party programs, mainly free apps;
  • spam e-mails from the unknown senders;
  • sites offering complimentary hosting;
  • P2P (peer-to-peer) torrent software.

There are times when the Kolz might camouflage itself as some genuine application, for example, through the deceptive informs demanding installation of some software upgrade. This is the most typical technique used by the frauds to inject the Kolz virus files into the system. By doing this users partially participate in its installation, without plainly understanding the risk.

In addition, the scams might send unsolicited spam e-mail with challenging signals motivating individuals to open dubious attachments or click some download links, for instance, those motivating individuals to open specific pictures, text files, tax files and other info.

No doubt, opening these files or clicking on the destructive links might essentially harm the system. Fake Acrobat Reader upgrade notifications may cause the Kolz ransomware seepage. Similarly, downloading the cracked software application might in addition consist of the ransomware installer. The last however not the least, installation of Kolz might take place through some Trojan horses that may be set up stealthily into the system and without the user’s direct consent and even authorization.

Preventing the Kolz attack.

Of course, there is no outright warranty that your computer system will be always devoid of any malware attacks, nevertheless, we wish to share some useful ideas with you to make it more secure. Ensure to pay extremely close attention while browsing the web and specifically while getting cost-free programs. Do not open any dubious e-mail attachments, specifically if the sender is not understood to you.

Do not forget that certain freeware installer may also include some other extra apps in the package. These additional applications might be really damaging. It is of utmost significance to keep your anti-virus software application and your operating system in basic to be constantly properly updated.

It is quite sensible that downloading cracked programs is prohibited, nevertheless, additionally, such unauthorized programs usage may likewise bring major damage to your system. Hence, do not download any split programs. Plus, the reality that your existing anti-virus did not secure the system from the Kolz ransomware is a good reason for you to reassess your options and change to another program that can render the securing functions on a far better level.

Below please find the quotation from the Kolz text file:

 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:

 Our Telegram account:

Screenshot of files with “.kolz” extension added by the ransomware:”

Kolz Ransomware - encrypt files with .kolz extension

Use GridinSoft Anti-Malware to remove Kolz ransomware from your computer

1.Download GridinSoft Anti-Malware.

You can get GridinSoft Anti-Malware by clicking the button below:

  GridinSoft Anti-Malware

2. Double-click on the setup file.

When setup file has finished downloading, double-click on the setup-antimalware-ag.exe file to install GridinSoft Anti-Malware on your computer.
GridinSoft Anti-Malware
An User Account Control asking you about to allow GridinSoft Anti-Malware to make changes to your device. So, you should click “Yes” to continue with the installation.
GridinSoft Anti-Malware Setup

3. Press Install button for run GridinSoft Anti-Malware.

GridinSoft Anti-Malware Install

3.Once installed, GridinSoft Anti-Malware will automatically run.

GridinSoft Anti-Malware  Start

4. Wait for the GridinSoft Anti-Malware scan to complete.

GridinSoft Anti-Malware will automatically start scanning your computer for Win Speedup 2018 and other malicious programs. This process can take a 20-30 minutes, so we suggest you periodically check on the status of the scan process.
GridinSoft Anti-Malware Scan

5. Click on “Clean Now”.

When the scan has completed, you will see the list of infections that GridinSoft Anti-Malware has detected. To remove them click on the “Clean Now” button in right corner.
GridinSoft Anti-Malware Scan Result

Use Emsisoft Decryptor for restore kolz files

You can get Emsisoft Decryptor by clicking the button below:

  Emsisoft Decryptor

  1. Run the decryptor as an administrator. The license terms will show up, which you have to agree to by clicking the “Yes” button.
  2. Once the license terms are accepted, the primary decryptor user interface opens.
  3. By default, the decryptor will pre-populate the locations to decrypt with the currently connected drives and network drives. Additional locations can be added using the Add” button.
  4. Decryptors typically offer various options depending on the particular malware family. The available options are located in the Options tab and can be enabled or disabled there. You can find a detailed list of the available Options below.
  5. After you have added all the locations you want to decrypt to the list, click the “Decrypt” button to start the decryption process. The screen will switch to a status view, informing you about the current process and decryption status of your files
  6. The decryptor will inform you once the decryption process is finished. If you require the report for your personal records, you can save it by clicking the “Save log” button. You can also copy it straight to your clipboard to paste it into emails or forum posts if you are asked to.
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About Daniel Zimmermann

Daniel Zimmermann has been writing on security and malware subjects for many years and has been working in the security industry for over 10 years. Daniel was educated at the Saarland University in Saarbrücken, Germany and currently lives in New York.

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  1. when I ran emisoft encryptor this message was displayed
    No key for New Variant online ID: xYO8n2VnR3ndGOLbwZNYb8gEeP5uRcjO4slMuD1n Notice: this ID appears to be an online ID, decryption is impossible
    could you please help me?

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