Djvu VirusRansomwareRemoval Guide

Kuus Virus Removal Guide (+Decrypt .kuus files)

Kuus – General Info

Kuus is a harmful software functioning as common ransomware. Michael Gillespie, the well-known malware researcher, very first found this new name in the DJVU ransomware family.

Kuus was created for the sole purpose to encrypt all popular file types. Logically, as soon as the file encryption is effectively achieved, the users are unable to get access to them. Kuus ransomware includes its own “.kuus” to all the encrypted files. For instance, the file “price_list.xls”, when crypted by Kuus, will be entitled as “price_list.xls.kuus”. As soon as the encryption is achieved, Kuus puts its own special text file (_readme.txt) into all the folders that save the encrypted files.

The alert specified by document requesting the random os very comparable to the alerts given by other ransomware dangers belonging to the DJVU family. The caution essentially indicates that the data has been encrypted and the only service to get access to it is to use a distinct standalone key. Regretfully, this declaration is absolutely true.

The approach to secure the files utilized by Kuus is not entirely looked into. Nevertheless, there is no doubt that each computer system owner may be provided a special decryption key, which is definitely unique. It is incredibly difficult to recover the data without the proper type in location.

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

message from Kuus virus

One more peculiarity of the Kuus infection is that the users are unable to get access to the key. The decrypting key is hosted on an unique server under the total control by the criminals who have launched the Kuus ransomware into the world wide web. In order to get the key and restore the important data, the users are told to get in touch with the frauds by means of email or by telegram and to pay the ransom in the amount of $980.

The message likewise says that the people need to get in touch with the Kuus authors within 72 hours upon the moment of the information file encryption. The alert shows that by doing so the people will get a 50% discount rate, therefore, the ransom quantity drops down to $490.

No matter what the quantity of the ransom is, we strongly encourage that you do not pay the ransom. There is no warranty that these online crooks will keep their guarantees, so they may not care at all what the victims feel about the file encryption, even when the amount of the ransom is received into their accounts. Thus, paying ransom often does not result in a successful recovery. So, the users may simply lose their money for absolutely nothing.

Likewise, we urge you not to contact the frauds as they advise. Do not transfer cash into their wallets. There are no applications that could break the Kuus ransomware or bring back the data at no charge. For that reason, the only correct choice is to restore the data from possible backups (if available).

Virus Summary

NameKuus Ransomware
File Extensionkuus
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 .kuus extension to all the files modified by it.
Distribution MethodAdware bundles and software cracks
Similar InfectionsBmic, Repl, Maas
Kuus Removal Tool   GridinSoft Anti-Malware
Kuus Decryption Tool   Emsisoft Djvu Decryptor

Do not forget that the Internet is now loaded with infections comparable to the Kuus virus. For example, this particular danger is generally identical to Brusaf and other ransomware-type infections. These harmful energies have been established in order to secure the essential information and reveal the need for the users to pay the ransom. All these infections utilize the identical algorithm to generate the particular key for effective data decryption.

Unless the Kuus ransomware is still under the advancement process or has actually got some hidden bugs, it is not possible to bring back the information by hand. Therefore, the only working solution to prevent the loss of your crucial data is to regularly preserve up-to-date backups of all your essential documents.

Another important piece of recommendations is to save the backups on unique storage not connected to your main computer. 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 regular drive is extremely risky, since the backup may likewise be encrypted by the Kuus ransomware.

Leaks for the Kuus ransomware attack.

Kuus uses many paths to penetrate the susceptible computers. It is not specific what particular method was utilized in your case, however, the invasion may occur through the following channels:

  • bundling with third-party programs, mainly free apps;
  • spam emails from the unidentified senders;
  • sites offering complimentary hosting;
  • P2P (peer-to-peer) torrent downloads.

There are times when the Kuus virus may disguise itself as some real application, for example, through the misleading alerts demanding setup of some software update. This is the most common technique used by the frauds to inject the Kuus infection files into the system. In this manner users partly participate in its setup, without plainly comprehending the danger.

Furthermore, the scams might send out unsolicited spam email with tricky notifies motivating the people to open dubious attachments or click some download links, for instance, those encouraging individuals to open specific images, text files, tax files and other info.

No doubt, opening these files or clicking the malicious links might basically damage the system. Fake Acrobat Reader upgrade alerts may result in the Kuus ransomware infiltration. Likewise, downloading the cracked software may in addition include the ransomware installer. The last however not the least, installation of Kuus might take place through some Trojan horses that might be set up stealthily into the system and without the user’s direct consent or perhaps consent.

Avoiding the Kuus ransomware injection.

Obviously, there is no absolute warranty that your computer system will be constantly free of any malware attacks, nevertheless, we wish to share some useful pointers with you to make it more secure. Make certain to pay extremely very close attention while browsing the web and specifically while downloading cost-free programs. Do not open any suspicious email attachments, especially if the sender is not understood to you.

Do not forget that particular freeware installer might likewise contain some other additional apps in the bundle. These additional applications may be extremely damaging. It is of utmost value to keep your anti-virus software application and your operating system in general to be always properly updated.

It is quite rational that downloading cracked programs is unlawful, nevertheless, furthermore, such unapproved apps usage might likewise bring major damage to your system. For this reason, do not download any broken programs. Plus, the fact that your existing anti-virus did not secure the system from the Kuus ransomware is an excellent reason for you to reevaluate your choices and change to another program that can render the safeguarding functions on a better level.

Below please find the quotation from the Kuus 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 “.kuus” extension added by the ransomware:”

Kuus Ransomware - encrypt files with .kuus extension

Use GridinSoft Anti-Malware to remove Kuus 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 kuus 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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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. Dear Sir, Any Decryption Tool For .kuus Ransomeware with online Key? Emsisoft Decryptor works only for offline id,


    File: D:\ransomeware test\balancesheet.xlsx.kuus
    No key for New Variant online ID: sQSjbDKtEoBdCweZMQugSRE2pdcmNp81zhXDRyby
    Notice: this ID appears to be an online ID, decryption is impossible


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