Djvu VirusRansomwareRemoval Guide

Kcbu Virus Removal Guide (+Decrypt .kcbu files)

Kcbu – General Info

Kcbu is a malicious software functioning as common ransomware. Michael Gillespie, the popular virus researcher, first discovered this new name in the DJVU ransomware family.

Kcbu was developed for the sole purpose to encrypt all popular file types. Rationally, as quickly as the encryption is effectively achieved, the users are not able to get access to them. Kcbu ransomware includes its own “.kcbu” to all the encrypted files. For instance, the file “price_list.xls”, when crypted by Kcbu, will be titled as “price_list.xls.kcbu”. When the encryption is achieved, Kcbu puts its own unique text document (_readme.txt) into all the folders that save the encrypted files.

The message specified by document requesting the random os very similar to the notices provided by other ransomware risks belonging to the DJVU family. The warning basically indicates that the information has been secured and the only option to get access to it is to use a special standalone key. Regretfully, this statement is absolutely true.

The method to secure the files utilized by Kcbu is not entirely investigated. Nevertheless, there is no doubt that each computer system owner might be provided a special decryption key, which is absolutely unique. It is exceptionally hard to recuperate the data without the suitable key in location.

“Don’t worry, you can return all your files!”, from text file message:

message from Kcbu virus

One more peculiarity of the Kcbu infection is that the users are not able to get access to the key. The decrypting key is hosted on a special server under the total control by the crooks who have actually launched the Kcbu infection into the world wide web. In order to acquire the key and bring back the important data, the users are told to get in touch with the frauds through e-mail or by telegram and to pay the ransom in the amount of $980.

The message likewise states that individuals ought to get in touch with the Kcbu authors within 72 hours upon the minute of the information file encryption. The alert suggests that by doing so individuals will get a 50% discount, for that reason, the ransom quantity drops down to $490.

No matter what the quantity of the ransom is, we highly recommend that you do not pay the ransom. There is no assurance that these online crooks will keep their promises, so they might not care at all what the victims feel about the encryption, even when the quantity of the ransom is received into their accounts. Hence, paying ransom often does not lead to an effective healing. So, the users might merely lose their money for absolutely nothing.

Similarly, we urge you not to call the scams as they instruct. Do not move cash into their wallets. There are no applications that might crack the Kcbu virus or bring back the data for free. Therefore, the only correct choice is to restore the information from possible backups (if available).

Virus Summary

NameKcbu Ransomware
File Extensionkcbu
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 .kcbu extension to all the files modified by it.
Distribution MethodAdware bundles and software cracks
Similar InfectionsLokas, Besub, Nusar
Kcbu Removal Tool   GridinSoft Anti-Malware
Kcbu Decryption Tool   Emsisoft Djvu Decryptor

Do not forget that the Web is now full of infections similar to the Kcbu ransomware. For example, this specific threat is essentially similar to Brusaf and other ransomware-type infections. These damaging energies have actually been established in order to encrypt the crucial information and express the demand for the users to pay the ransom. All these infections use the similar algorithm to generate the particular key for effective files decryption.

Unless the Kcbu ransomware is still under the advancement process or has actually got some concealed bugs, it is not possible to restore the data manually. Hence, the only working solution to avoid the loss of your crucial data is to routinely keep current backups of all your crucial data.

Another crucial piece of recommendations is to keep the backups on unique storage not connected to your main computer. For instance, you may store it on the USB Flash Drive, or some external drive, or by using the cloud data storage services. Keeping the backups on your regular drive is very dangerous, given that the backup might also be encrypted by the Kcbu .

Leakages for the Kcbu ransomware attack.

Kcbu uses lots of paths to penetrate the vulnerable computer systems. It is not specific what specific approach was utilized in your case, however, the intrusion might happen through the following channels:

  • bundling with third-party programs, primarily freeware;
  • spam emails from the unidentified senders;
  • websites offering free hosting;
  • P2P (peer-to-peer) torrent downloads.

There are times when the Kcbu ransomware may camouflage itself as some real application, for example, through the deceptive notifies requiring installation of some software update. This is the most typical trick utilized by the scams to inject the Kcbu virus files into the system. In this manner users partially take part in its setup, without clearly comprehending the risk.

In addition, the frauds might send out unsolicited spam email with tricky signals motivating the people to open dubious attachments or click some download links, for example, those motivating the people to open certain images, text files, tax files and other information.

No doubt, opening these files or clicking the harmful links may basically damage the system. Fake Acrobat Reader update notices may lead to the Kcbu ransomware seepage. Likewise, downloading the cracked software application may furthermore include the ransomware installer. The last however not the least, installation of Kcbu might happen through some Trojan horses that might be set up stealthily into the system and without the user’s direct authorization or perhaps approval.

Preventing the Kcbu ransomware injection.

Naturally, there is no outright warranty that your computer will be always without any malware attacks, however, we would like to share some beneficial suggestions with you to make it much safer. Ensure to pay really very close attention while searching the web and especially while getting cost-free programs. Do not open any suspicious email attachments, especially if the sender is not understood to you.

Do not forget that specific freeware installer may likewise contain some other additional apps in the bundle. These extra applications may be extremely damaging. It is of utmost significance to keep your anti-virus software and your operating system in basic to be constantly effectively updated.

It is rather logical that downloading pirated software is illegal, nevertheless, additionally, such unauthorized programs use might also bring severe damage to your computer. For this reason, do not download any split programs. Plus, the truth that your existing anti-virus did not protect the system from the Kcbu ransomware is a good reason for you to reassess your choices and change to another program that can render the securing functions on a better level.

Below please find the quotation from the Kcbu 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 “.kcbu” extension added by the virus:”

Kcbu Ransomware - encrypt files with .kcbu extension

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

1.Download GridinSoft Anti-Malware.

You can download 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 kcbu files

You can download 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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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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