VOOK Virus (.vook File) Ransomware

Written by Brendan Smith

The Vook virus, also known as a ransomware, belongs to the STOP/DJVU family. This malware is known for file encryption and extortion. When the Vook virus gets into a computer system, it scans the system for files like videos, photos, documents, and more. It modifies the file structure and appends the “.vook” extension to each encrypted file, making them unusable without the decryptor.

Vook Virus Overview

Vook

🤔 Vook virus can be classified as ransomware that originates from the DJVU/STOP ransomware family. Its main target is to cipher all of your files it can reach. After that ransomware virus asks its victims for a ransom payment – ($499 – $999) in Bitcoin.

The Vook virus is a type of malware that encrypts your files and coerces you into paying for their restoration. This malware encrypts different file types. ciphered files can be identified by a distinct “.vook” extension. As a result, the affected files become inaccessible and unusable.

Subsequently, the ransomware asks for a file decryption payment in Bitcoin from its victims, that ranges from $499 to $999, depending on the time passed after the attack. Typically, a ransom text file is named as “_readme.txt“.

Vook Ransomware works with Salsa20 encryption algorithms to cipher the files. Since Vook virus utilizes such a robust encryption method, it becomes incredibly difficult, if not impossible, to pick the decryption key without the assistance of the attackers.

Once Vook malware finishes the encryption, it shows a ransom note to the victim, asking for a ransom payment in exchange for the decryption key. The ransom note contains instructions on the ways of making the payment and often includes threats of permanent data loss or ransom amounts surge if the ransom is not paid within a specified timeframe.

I have made a comprehensive list of potential solutions, tips, and methods to neutralize the Vook ransomware and decrypt and recover your files. There are cases when it may be feasible to restore your files, but sometimes, it may be impossible.

Brendan Smith
Brendan Smith
IT Security Expert
First, perform a PC scan using an antivirus tool!
I will assist you in removing the Vook virus and guide you through the process of decrypting or restoring encrypted files. Below, you will find several universally applicable methods to recover encrypted .vook files. It is crucial to thoroughly read and comprehend the entire set of instructions. Do not skip any steps. Each step is of utmost importance and must be completed by you.
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📌 Important Note!

It is crucial to say that paying off the bill does not guarantee the successful recovery of your files. The individuals behind the Vook virus are not trustworthy. There were the cases where victims have paid the ransom, only to be denied by the cybercriminals with the decryption key provision.

Vook uses a unique key for each victim, with one exception:

  • If Vook fails to connect the command and control server (C2) before starting the encryption process, it resorts to using offline keys. This key is the same for all users, allowing for the decryption of files encrypted by the ransomware.

The Vook virus bears resemblance to other DJVU ransomware variants like Looy, Kool, Nood, and Wiaw. This virus encrypts a wide range of common file types and appends its distinct “.vook” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.vook” and “2.png” to “2.png.vook“.

After successful encryption, the virus spawns a special text file named “_readme.txt” and places it in every folder containing the encrypted files. It as well adds the readme file to the desktop, so the user will not miss the attack even without opening folders.

The image below provides a visual representation of files with the “vook” extension:

Vook Virus - encrypted vook files

Encrypted Files by STOP/DJVU Ransomware

NameVook Virus
Ransomware family1DJVU/STOP2 ransomware
Extension.vook
Ransomware note_readme.txt
RansomFrom $499 to $999 (in Bitcoins)
Contactsupport@freshingmail.top, datarestorehelpyou@airmail.cc
DetectionTrojan:MSIL/Lokibot.PA!MTB Virus Removal, Trojan:MSIL/AsyncRat.NE!MTB Virus Removal, Ransom:MSIL/FileCoder.YG!MTB Virus Removal
Symptoms
  • Installs password-stealing Trojan on the system, like Vidar Stealer or RedLine Stealer;
  • Adds a list of domains to HOSTS file to block access to certain security-related sites;
  • Encrypts most of your files (photos, videos, documents) and adds a particular “.vook” extension;
  • Manages to install a SmokeLoader backdoor;
  • Can delete Volume Shadow copies to make victim’s attempts to restore data impossible;
Fix Tool To remove possible malware infections, scan your PC:


6-day free trial available.

This message asking payment is for restore files via decryption key:

_readme.txt (STOP/DJVU Ransomware)

_readme.txt (STOP/DJVU Ransomware) – The alarming alert demanding users to pay off the ransom to unlock the encoded data contains these annoying admonitions.

Vook ransomware arrives as a set of operations that are used to perform different functions on a victim’s computer. One of the primary processes being launched is winupdate.exe, a deceptive process that displays a false Windows update prompt during the attack. This is meant to convince the victim that a sudden PC slowdown is caused by a Windows update.

At the same time, the ransomware runs another process (named as 4 random chars) which starts scanning the system for target files and ciphering them. Then the ransomware removes Volume Shadow Copies from the disk using the following CMD command:

vssadmin.exe Delete Shadows /All /Quiet

Once deleted, it becomes nearly impossible to retrieve the previous computer state using System Restore Points. The issue is, ransomware operators are getting rid of any built-in Windows approaches that could aid the victim to regain files for free. In addition, the crooks modify the Windows HOSTS file by including a list of domains to it and mapping them to the localhost IP. As a result, the victim will encounter a DNS_PROBE_FINISHED_NXDOMAIN error when accessing one of the blacklisted websites.

We noticed that ransomware attempts to restrict websites that post various how-to guides for computer users. It is obvious that by restricting specific domains, the malefactors are seeking to hinder the victim from connecting to relevant and helpful ransomware-attack-related information online. This malware also stores two .txt files on the victim’s computer that provide details related to the attack – the public key of this victim and personal ID. These two files are named bowsakkdestx.txt and PersonalID.txt.

Vook ransomware virus saves public encryption key and victim's id in bowsakkdestx.txt file

After all these changes, the malware doesn’t halt. Variants of STOP/DJVU are inclined to deploy Vidar password-stealing Trojan on compromised systems. This threat has an large list of capabilities, including:

  • Gathering sensitive data by running malicious software on the victim’s computer.
  • Acquiring unauthorized login credentials of Steam, Telegram, and Skype accounts.
  • Manipulating and viewing files on the victim’s computer without their knowledge.
  • Stealing cryptocurrency wallets from the victim’s system.
  • Granting the hackers remote control over the victim’s computer for various malicious activities.
  • Extracting sensitive information such as browser cookies, saved passwords, and browsing history.

The cryptography algorithm used by DJVU/STOP virus is AES-256. So, if your data got encrypted with an online decryption key, the possibility to get your files back are quite low. Thing is, this key is unique for each victim, and finding a suitable one will take too much time.

Retrieving the online decryption key in any other way is also merely impossible. It is stored on a server controlled by the criminals who spread the Vook malware. For receiving unlocking key the payment should be $999. To see the payment details, the victims should contact the hackers by email (support@fishmail.top).

The message by the ransomware states the following information:

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://we.tl/t-hPAqznkJKD
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

How To Remove STOP/Djvu Ransomware?

Remove Vook Virus with Gridinsoft Anti-Malware

We have also been using this software on our systems ever since, and it has always been successful in detecting viruses. It has blocked the most common Ransomware as shown from our tests with the software, and we assure you that it can remove Vook Virus as well as other malware hiding on your computer.

Gridinsoft Anti-Malware - Main Screen

To use Gridinsoft for remove malicious threats, follow the steps below:

1. Begin by downloading Gridinsoft Anti-Malware, accessible via the blue button below or directly from the official website gridinsoft.com.

2.Once the Gridinsoft setup file (setup-gridinsoft-fix.exe) is downloaded, execute it by clicking on the file.

setup-gridinsoft-fix.exe

3.Follow the installation setup wizard's instructions diligently.

Gridinsoft Setup Wizard

4. Access the "Scan Tab" on the application's start screen and launch a comprehensive "Full Scan" to examine your entire computer. This inclusive scan encompasses the memory, startup items, the registry, services, drivers, and all files, ensuring that it detects malware hidden in all possible locations.

Scan for Vook Virus Ransomware

Be patient, as the scan duration depends on the number of files and your computer's hardware capabilities. Use this time to relax or attend to other tasks.

5. Upon completion, Anti-Malware will present a detailed report containing all the detected malicious items and threats on your PC.

The Vook Virus was Found

6. Select all the identified items from the report and confidently click the "Clean Now" button. This action will safely remove the malicious files from your computer, transferring them to the secure quarantine zone of the anti-malware program to prevent any further harmful actions.

The Vook Virus has been removed

8. If prompted, restart your computer to finalize the full system scan procedure. This step is crucial to ensure thorough removal of any remaining threats. After the restart, Gridinsoft Anti-Malware will open and display a message confirming the completion of the scan.

Remember Gridinsoft offers a 6-day free trial. This means you can take advantage of the trial period at no cost to experience the full benefits of the software and prevent any future malware infections on your system. Embrace this opportunity to fortify your computer's security without any financial commitment.

Trojan Killer for “Vook Virus” removal on locked PC

In situations where it becomes impossible to download antivirus applications directly onto the infected computer due to malware blocking access to websites, an alternative solution is to utilize the Trojan Killer application.

Trojan Killer - Main View

There is a really little number of security tools that are able to be set up on the USB drives, and antiviruses that can do so in most cases require to obtain quite an expensive license. For this instance, I can recommend you to use another solution of GridinSoft - Trojan Killer Portable. It has a 14-days cost-free trial mode that offers the entire features of the paid version. This term will definitely be 100% enough to wipe malware out.

Trojan Killer is a valuable tool in your cybersecurity arsenal, helping you to effectively remove malware from infected computers. Now, we will walk you through the process of using Trojan Killer from a USB flash drive to scan and remove malware on an infected PC. Remember, always obtain permission to scan and remove malware from a computer that you do not own.

Step 1: Download & Install Trojan Killer on a Clean Computer:

1. Go to the official GridinSoft website (gridinsoft.com) and download Trojan Killer to a computer that is not infected.

Download Trojan Killer

2. Insert a USB flash drive into this computer.

3. Install Trojan Killer to the "removable drive" following the on-screen instructions.

Install Trojan Killer to Removable Drive

4. Once the installation is complete, launch Trojan Killer.

Step 2: Update Signature Databases:

5. After launching Trojan Killer, ensure that your computer is connected to the Internet.

6. Click "Update" icon to download the latest signature databases, which will ensure the tool can detect the most recent threats.

Click Update Button

Step 3: Scan the Infected PC:

7. Safely eject the USB flash drive from the clean computer.

8. Boot the infected computer to the Safe Mode.

9. Insert the USB flash drive.

10. Run tk.exe

11. Once the program is open, click on "Full Scan" to begin the malware scanning process.

Searching Vook Virus Virus

Step 4: Remove Found Threats:

12. After the scan is complete, Trojan Killer will display a list of detected threats.

Searching Vook Virus Finished

13. Click on "Cure PC!" to remove the identified malware from the infected PC.

14. Follow any additional on-screen prompts to complete the removal process.

Restart needed

Step 5: Restart Your Computer:

15. Once the threats are removed, click on "Restart PC" to reboot your computer.

16. Remove the USB flash drive from the infected computer.

Congratulations on effectively removing Vook Virus and the concealed threats from your computer! You can now have peace of mind, knowing that they won't resurface again. Thanks to Gridinsoft's capabilities and commitment to cybersecurity, your system is now protected.

Video Guide


How To Decrypt .vook Files?

How to restore big files?

Try deleting .vook extension on a few big files and opening them. This malware has issues with large files encryption. Either the virus scanned and did not encode the file, or it failed and did not add the filemarker. If your files are very large (2GB+), the latter is most likely. Please, text me in the comments whether this helped you or not.

The newest extensions released around the end of August 2019 after the criminals made changes. This includes Looy, Kool, Nood etc.

As a result of the changes made by the criminals, STOPDecrypter is no longer assisted. It has been replaced with the Emsisoft Decryptor for STOP Djvu Ransomware developed by Emsisoft.

You can download free decryption tool here: Decryptor for STOP Djvu.

  1. Download and run decryption tool.

    Start downloading the decryption tool.

    Make sure to launch the decryption utility as an administrator. You need to agree with the license terms that will come up. For this purpose, click on the “Yes” button:

    Emsisoft Decryptor - license terms

    As soon as you accept the license terms, the main decryptor user interface comes up:

    Emsisoft Decryptor - user interface

  2. Select folders for decryption.

    Based on the default configurations, the decryptor will automatically choose the reachable directories in order to decode the currently available drives (the connected ones), including the network drives. Extra (optional) locations can be selected with the assistance of the “Add” button.

    Decryptors usually offer several options considering the specific malware family. The existing possible options are presented in the Options tab and can be activated or deactivated there. You may locate a detailed list of the currently active Options below.

  3. Click on the “Decrypt” button.

    As soon as you add all the desired locations for decryption into the list, click on the “Decrypt” button in order to initiate the decryption procedure.

    Note that the main screen may turn you to a status view, letting you know of the active process and the decryption statistics of your data:

    Emsisoft Decryptor - the decryption statistics

    The decryptor will notify you as soon as the decryption procedure is completed. If you need the report for your personal papers, you can save it by choosing the “Save log” button. Note that it is also possible to copy it directly to your clipboard and to paste it into emails or messages here if you need to do so.

The Emsisoft Decryptor might display different messages after a failed attempt to restore your files:

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

Emsisoft does not have a corresponding key in the database.

✓ No key for New Variant online ID: [your ID]

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

Malware used an online key to cipher your files. There is no one to share the decryption key with you. Recovery of files without paying the criminals is impossible. 🙁

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

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

Malware used an offline key, but files could not be restored (the offline decryption key isn’t available yet). But, receiving this message is good news for you, since it is possible to restore your files in the future. 🙂

It can take a few weeks or months until the decryption key gets found and uploaded to the decryptor. Please follow updates regarding the decryptable DJVU versions here.

✓ Remote name could not be resolved

This stands for a DNS issues. Consider resetting your HOSTS file to default.

How to Restore .vook Files?

In some case ransomware is not doom for your files…

The Vook ransomware encryption algorithm is next: it ciphers every file byte-by-byte, then saves a duplicate, removing (not overriding!) the initial file. Hence, the information of the file location on the disk drive is lost, but the original file is not erased from the physical disk. The cell, or the sector where this file was stored, can still hold this file, but it is not present in the file system and can be rewritten by data that has been loaded to this drive after the deletion. Hence, it is possible to restore your files using special software.

I recently had my pc infected by the this virus. It managed to bypass 2 Antivirus software and 2 malware fighters.

Anyway, after realizing it was an online algorithm, it is impossible to retrieve my encrypted files. I also had my backup drive plugged in at the time of the virus, and this was also infected, or so I thought. Every folder within my backup drive had been infected and was encrypted. However, despite losing some important files, I retrieved almost 80% of my 2TB storage.

When I started going through the folders, I noticed the readme.txt ransom note in every folder. I opened some of the folders and found that all files that were not in a subfolder within that folder had been encrypted. However, I found a flaw and glimmer of hope when I went into the subfolders in other folders and found that these files had not been encrypted. Every folder within my c and d drives, including subfolders, had been encrypted, but this was not the case with the backup drive. Having subfolders created within a folder has saved 80% of my data.

As I said, I believe this to be only a small loophole on a backup drive. I’ve since found a further 10 % of my data on another hard drive on a different pc. So my advice is if you use a backup drive, create subfolders. I was lucky, I guess. But I was also unlucky that the virus hit as I was transferring some files from my backup.

Hopefully, this can help some other people in my situation.

Jamie Newland
Some pointers for recovery repair of Vook files (true for all STOP/DJVU variants):

  • I have seen Stop/Djvu variants fail to encrypt deeper nested folders, so that you can check that. You may find those are not encrypted.
  • This ransomware saves encrypted data to a new file, deletes the original. So there’s a slight chance part of that deleted file can be recovered using file recovery software. It’s unlikely the folder structure can be restored, so a free tool like PhotoRec may be as good as any.
  • This ransomware only partially encrypts (about the first 150 KB), so depending on file size and type of data, the not encrypted part may be recoverable.
  • Joep

    Recovering your files with PhotoRec

    PhotoRec is an open-source program, which is initially created for file retrieval from damaged disks, or for files recovery in case if they are unintentionally deleted. However, as time has gone by, this program adopted the ability to restore the files of 400 different extensions. Hence, it can be used for file restoration after the Vook attack.

    First, you need to download this app. It is 100% free, but the developer states that there is no warranty that your files will be restored. PhotoRec is spread together with another tool of the same developer – TestDisk. The program archive will have TestDisk name, but don’t worry. PhotoRec files are right inside.

    To open PhotoRec, you need to find and open “qphotorec_win.exe” file. No installation process is required – this program has all the files it need inside of the archive, hence, you can fit it on your USB drive, and try to help your friends/parents/anyone who has been attacked by Vook ransomware.

    PhotoRec file in the folder for restore Vook files

    After the launch, you will observe the screen showing you the full list of your disks. However, this data is likely futile, because the required menu is placed a bit higher. Click this bar, then choose the disk which was attacked by ransomware.

    Choose the disc in PhotoRec

    After choosing the disk, you need to select the destination folder for the reclaimed files. This menu is located at the lower part of the PhotoRec window. The best choice is to export them on USB drive or any other type of removable disk.

    Choosing the destination folder of recovery Vook files

    Then, you need to designate the file formats. This setting is located at the bottom, too. As it was mentioned, PhotoRec can recover the files of about 400 different formats.

    Choose the file format

    Finally, you can begin files recovery by pressing the “Search” button. You will observe the screen where the outcomes of the scan and recovery are shown.

    Recovery process

    Vook files recovery Video Guide.


    Frequently Asked Questions

    🤔 How can I open “.vook” files?

    No way. These files are encrypted by ransomware. The contents of encrypted files are not available until they are decrypted.

    🤔 This virus has blocked infected PC: I can’t get the activation code.

    In this situation, you need to prepare the memory stick with a pre-installed Trojan Killer.

    🤔 Decryptor did not decrypt all my files, or not all of them were decrypted. What should I do?

    Have patience. You are infected with the new version of STOP/DJVU ransomware, and decryption keys have not yet been released. Follow the news on our website.

    We will keep you posted on when new keys or new decryption programs appear.

    🤔 What can I do right now?

    The Vook ransomware encrypts only the first 150KB of files. So MP3 files are rather large, some media players (Winamp for example) may be able to play the files, but – the first 3-5 seconds (the encrypted portion) will be missing.

    You can try to find a copy of an original file that was encrypted:

    • Files you downloaded from the Internet that were encrypted and you can download again to get the original.
    • Pictures that you shared with family and friends that they can just send back to you.
    • Photos that you uploaded on social media or cloud services like Carbonite, OneDrive, iDrive, Google Drive, etc
    • Attachments in emails you sent or received and saved.
    • Files on an older computer, flash drive, external drive, camera memory card, or iPhone where you transferred data to the infected computer.

    If the guide doesn’t help you to remove infection, please download the GridinSoft Anti-Malware that I recommended. Do not forget to share your experience in solving the problem. Please leave a comment here! This can help other victims to understand they are not alone. And together we will find ways to deal with this issue.

    I need your help to share this article.

    It is your turn to help other people. I have written this guide to help people like you. You can use buttons below to share this on your favorite social media Facebook, Twitter, or Reddit.

    Brendan Smith
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    References

    1. My files are encrypted by ransomware, what should I do now?
    2. About DJVU (STOP) Ransomware.

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    About the author

    Brendan Smith

    I'm Brendan Smith, a passionate journalist, researcher, and web content developer. With a keen interest in computer technology and security, I specialize in delivering high-quality content that educates and empowers readers in navigating the digital landscape.

    With a focus on computer technology and security, I am committed to sharing my knowledge and insights to help individuals and organizations protect themselves in the digital age. My expertise in cybersecurity principles, data privacy, and best practices allows me to provide practical tips and advice that readers can implement to enhance their online security.

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