GAYN Virus File Decrypt & Removal

Written by Brendan Smith

While I was analyzing malware samples submitted to VirusTotal1, I made an intriguing discovery: the Gayn ransomware is actively encrypting files and adding the “.gayn” extension to their original filenames. In simpler terms, it takes a file like “a.jpg” and renames it as “a.jpg.gayn“, or transforms “b.doc” into “b.doc.gayn“. This ransomware has truly wreaked havoc on countless victims.

Gayn belongs to the Djvu family, which is known for its association with other malware, such as Vidar Stealer and RedLine Stealer, which are information stealers. Threat actors have been observed distributing ransomware from the Djvu family along with these malicious programs.

GAYN

🤔 GAYN virus is ransomware that originates from the DJVU/STOP family. Its primary purpose is to encrypt files that are important to you. After that ransomware virus asks its victims for a ransom fee ($490 – $980) in Bitcoin.

Feeling compelled to help those affected, I have compiled an extensive and comprehensive list of potential solutions, invaluable tips, and best practices to combat the destructive Gayn virus and regain access to encrypted files. However, I must emphasize that the success of file recovery heavily depends on the unique circumstances surrounding each case, and in some unfortunate situations, recovery may prove to be an insurmountable challenge.

Interestingly, the Gayn ransomware employs a distinct encryption key for each victim, except for one exceptional scenario:

  • If the ransomware fails to establish a connection with its command and control server (C&C Server) before initiating the encryption process, it resorts to using an offline key. This specific key is shared among all victims, providing a glimmer of hope for those affected by this malicious ransomware attack. It means there is a possibility of decrypting files that have fallen victim to this devastating cyber assault.
Brendan Smith
Brendan Smith
IT Security Expert
First, scan your PC with antivirus tool!
I will try to help you remove Gayn virus and will show how to decrypt or restore encrypted files. There are several universal methods for recovering encrypted .gayn files, which will be demonstrated below. It is vital to read the entire instruction manual carefully and make sure to understand it all. Do not skip any steps. Each of these steps is very important and must be completed by you.
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What is Gayn virus?

☝️ It can be correctly identify as a STOP/DJVU ransomware virus.

The Gayn ransomware is a kind of threat that encrypted your files and then forces you to pay for them. The image below gives a clear vision of how the files with “.gayn” extension look like:

Gayn Virus - encrypted .gayn files

Gayn File (STOP/DJVU Ransomware)

Name Gayn Virus
Ransomware family2 DJVU/STOP3 ransomware
Extension .gayn
Ransomware note _readme.txt
Ransom From $490 to $980 (in Bitcoins)
Contact [email protected], [email protected]
Detection Win32.Virlock.Gen.4, NSIS/Injector.MK, Generic.Trojan.Malicious.DDS
Symptoms
  • Encrypted most of your files (photos, videos, documents) and adds a particular “.gayn” extension;
  • Can delete Volume Shadow copies to make victim’s attempts to restore data impossible;
  • Adds a list of domains to HOSTS file to block access to certain security-related sites;
  • Installs password-stealing Trojan on the system, like Vidar Stealer or RedLine Stealer;
  • Manages to install a SmokeLoader backdoor;
Fix Tool To remove possible malware infections, scan your PC:


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This _readme.txt file asking payment is for restore files via decryption key:

_readme.txt (STOP/DJVU Ransomware)

_readme.txt (STOP/DJVU Ransomware) – The scary alert demanding from users to pay the ransom to decrypt the encoded files contains these frustrating warnings

The Gayn ransomware arrives as a set of processes that are meant to perform different tasks on a victim’s computer. One of the first ones being launched is winupdate.exe, a tricky process that displays a fake Windows update prompt during the attack. This is meant to convince the victim that a sudden system slowdown is caused by a Windows update. However, at the same time, the ransomware runs another process (usually named by four random characters) which starts scanning the system for target files and encrypting them. Next, the ransomware deletes Volume Shadow Copies from the system using the following CMD command:

vssadmin.exe Delete Shadows /All /Quiet

Once deleted, it becomes impossible to restore the previous computer state using System Restore Points. The thing is, ransomware operators are getting rid of any Windows OS-based methods that could help the victim to restore files for free. In addition, the crooks modify the Windows HOSTS file by adding a list of domains to it and mapping them to the localhost IP. As a result, the victim will run into a DNS_PROBE_FINISHED_NXDOMAIN error when accessing one of the blocked websites.

We noticed that ransomware attempts to block websites that publish various how-to guides for computer users. It is evident that by restricting specific domains, the crooks are trying to prevent the victim from reaching relevant and helpful ransomware-attack-related information online. The virus also saves two text files on the victim’s computer that provide attack-related details – the victim’s public encryption key and personal ID. These two files are called bowsakkdestx.txt and PersonalID.txt.

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

After all these modifications, the malware doesn’t stop. Variants of STOP/DJVU tend to drop Vidar password-stealing Trojan on compromised systems. This threat has a lengthy list of capabilities, such as:

  • Stealing Steam, Telegram, Skype login / password;
  • Stealing cryptocurrency wallets;
  • Downloading malware to the computer and running it;
  • Stealing browser cookies, saved passwords, browsing history, and more;
  • Viewing and manipulating files on victim’s computer;
  • Allowing the hackers to perform other tasks on the victim’s computer remotely.

The cryptography algorithm used by DJVU/STOP virus is AES-256. So, if your data got encrypted with an online decryption key, which is totally unique. The sad reality is that it is impossible to decrypt the files without the unique key.

In case if Gayn worked in online mode, it is impossible for you to gain access to the AES-256 key. It is stored on a distant server owned by the frauds who promote the Gayn virus.

For receiving decryption key the payment should be $980. To obtain the payment details, the victims are encouraged by the message to contact the frauds by email ([email protected]).

The message by the ransomware states the following information:

ATTENTION!

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:

https://we.tl/t-WJa63R98Ku

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:

[email protected]

Reserve e-mail address to contact us:

[email protected]

Your personal ID:
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Do not pay for ransom!

Please, try to use the available backups, or Decrypter tool

The _Readme.txt file states that computer owners must contact the Gayn representatives within 72 hours from the moment the files were encrypted in order to receive a 50% rebate, reducing the ransom amount to $490. However, it is strongly advised not to pay the ransom or engage with these fraudulent individuals.

I strongly recommend avoiding any contact with these scammers and refraining from making any payments. The most effective solution to recover the lost data is to utilize available backups or use the Decrypter, PhotoRec and Gridinsoft Anti-Malware.

All these types of viruses follow a similar procedure to generate a unique decryption key for recovering the encrypted data. Unless the ransomware is still in the developmental stage or possesses hard-to-detect flaws, manual recovery of the encrypted data is not feasible. The only reliable method to safeguard your valuable data is to regularly create backups of your crucial files.

It is important to note that even if you maintain regular backups, they should be stored in a secure location separate from your main workstation. For example, you can store the backup on a USB flash drive or an external hard drive. Alternatively, you can utilize online (cloud) storage services for backup purposes.

It goes without saying that keeping your backup data on the same device as your main computer is not a wise decision. Doing so could result in the backup data being encrypted along with the rest of your files. Therefore, it is essential to store your backups in a separate and secure location.

How I was infected?

Ransomware has a various methods to built into your system. But it doesn’t really matter what method was used in your case.

Gayn ransomware attack

Gayn virus attack following a successful phishing attempt.

However, there are common ways through which the STOP/Djvu ransomware may infiltrate your PC:

  • It can be secretly installed alongside other apps, particularly utilities that are offered as freeware or shareware.
  • Another way is through suspicious links in spam emails, leading to the installation of the virus.
  • Online free hosting resources can also serve as a source of infiltration.
  • Additionally, downloading pirated software from illegal peer-to-peer (P2P) resources can result in the injection of the Gayn ransomware.

Instances have been reported where the virus disguised itself as a legitimate tool, often appearing in messages that demand unwanted software or browser updates. This is how online fraudsters manipulate users, coercing them into manually installing the Gayn ransomware, thereby involving them directly in the installation process.

It’s worth noting that the fake update alerts will not explicitly indicate the virus installation. Instead, these alerts typically mention the need to update Adobe Flash Player or some other dubious program.

Moreover, using cracked applications poses a significant risk. Engaging in illegal P2P activities not only violates copyright laws but also exposes users to serious malware, including the Gayn ransomware.

In conclusion, what steps can you take to protect your device from the Gayn ransomware? Although there is no foolproof method, I would like to provide you with some helpful tips to prevent the infiltration of Gayn. When installing free software, be cautious and carefully review what the installers offer in addition to the main program. Avoid opening attachments from suspicious emails or files from unknown senders. It is essential to keep your security program updated at all times.

The malware does not reveal itself openly. It won’t appear in the list of your available programs. Instead, it operates discreetly in the background, starting as soon as you launch your computer.

How To Remove Gayn Virus?

In addition to encode a victim’s files, the virus has also started to install the Vidar Stealer on computer to steal account credentials, cryptocurrency wallets, desktop files, and more.


  1. Download Removal Tool.

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

  2. Run the setup file.

    When setup file has finished downloading, double-click on the setup-antimalware-fix.exe file to install GridinSoft Anti-Malware on your computer.

    Run Setup.exe

    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.

    GridinSoft Anti-Malware Install

  4. Once installed, Anti-Malware will automatically run.

    GridinSoft Anti-Malware Splash-Screen

  5. Wait for complete.

    GridinSoft Anti-Malware will automatically start scanning your PC for Gayn infections and other malicious programs. This process can take a 20-30 minutes, so I suggest you periodically check on the status of the scan process.

    Gayn Ransomware Files in the Scanning Process

  6. Click on “Clean Now”.

    When the scan has finished, 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.

    Gayn Files in the Scan Result
  7. Trojan Killer for special instances

    In some certain instances, ransomware can block the running of setup files of different anti-malware programs. In this situation, you need to utilize the removable drive with a pre-installed antivirus tool.

    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 4. This term will definitely be 100% enough to wipe malware out.

How To Decrypt .gayn Files?

How to restore big .gayn files?

Try removing .gayn extension on a few BIG files and opening them. Either the ransomware read and did not encrypt the file, or it bugged and did not add the filemarker. If your files are very large (2GB+), the latter is most likely. Please, let me know in comments if that will work for you.

The newest extensions released around the end of August 2019 after the criminals made changes. This includes Wazp, Wayn, Aghz, etc.

As a result of the changes made by the criminals, STOPDecrypter is no longer supported. It has been removed and 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 settings, the decryptor will automatically populate the available locations in order to decrypt the currently available drives (the connected ones), including the network drives. Extra (optional) locations can be selected with the help of the “Add” button.

    Decryptors normally suggest several options considering the specific malware family. The current 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 for .Gayn Files

    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 gayn files:

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

There is no corresponding decryption key in the Emsisoft decryptor’s database.

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

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

Your original files were encrypted with an online key. So no one else has the same encryption/decryption key pair. Recovery of gayn 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.

An offline key was used, but files could not be restored (the offline decryption key isn’t available yet). But, receiving this message is good news for you, because it might be possible to restore your gayn 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

It’s an indication of a DNS issue on your PC. Our first recommendation is to reset your HOSTS file back to default.

How to Restore .gayn Files?

In some case ransomware is not doom for your files…

The STOP/Djvu ransomware encryption mechanism feature is next: it encrypts every file byte-by-byte, then saves a file copy, deleting (and not overriding!) the original file. Hence, the information of the file location on the physical disk is lost, but the original file is not deleted from the physical disk. The cell, or the sector where this file was stored, can still contain this file, but it is not listed by the file system and can be overwritten by data that has been loaded to this disk after the deletion. Hence, it is possible to recover your files using special software.

I recently had my pc infected by the Gayn 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 Gayn files (true for all STOP/DJVU variants):

  • I have seen Gayn 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 originally created for files recovery from damaged disks, or for files recovery in case if they are deleted. However, as time has gone by, this program got the ability to recover the files of 400 different extensions. Hence, it can be used for data recovery after the ransomware attack

    At first, you need to download this app. It is 100% free, but the developer states that there is no guarantee that your files will be recovered. PhotoRec is distributed in a pack with other utility of the same developer – TestDisk. The downloaded 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 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 friend/parents/anyone who was been attacked by DJVU/STOP ransomware.

    PhotoRec file in the folder

    After the launch, you will see the screen showing you the full list of your disk spaces. However, this information is likely useless, 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 choose the destination folder for the recovered files. This menu is located at the lower part of the PhotoRec window. The best desicion is to export them on USB drive or any other type of removable disk.

    Choosing the destination folder for Gayn files recovery

    Then, you need to specify the file formats. This option 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 start files recovery by pressing the “Search” button. You will see the screen where the results of the scan and recovery are shown.

    Recovery process

    Gayn files recovery guide


    Frequently Asked Questions

    🤔 How can I open “.gayn” files?

    It is not possible to open “.gayn” files as they are encrypted by ransomware. The contents of these files remain inaccessible until they are decrypted.

    🤔 How can I urgently decrypt Gayn files that contain important information?

    If your data in the .gayn files is highly valuable, there is a possibility that you have a backup copy. In case you don’t have a backup, you can attempt to restore them using the system function called Restore Point. However, other methods might require patience.

    🤔 If I use GridinSoft Anti-Malware to remove Gayn, will it delete my encrypted files?

    Certainly not. Your encrypted files do not pose any threat to your computer. The encryption has already taken place.

    GridinSoft Anti-Malware is designed to eliminate active system infections. The virus responsible for encrypting your files might still be active and periodically conducting tests to encrypt additional files. Additionally, these viruses often install keyloggers and backdoors to facilitate further malicious actions, such as password and credit card theft.

    🤔 The computer virus has locked my PC, and I can’t obtain the activation code. What should I do?

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

    🤔 The decryptor failed to decrypt all of my files or only partially decrypted them. What steps should I take?

    Exercise patience as you are dealing with the new version of STOP/DJVU ransomware, and the decryption keys have not yet been released. Stay updated by following the news on our website.

    We will keep you informed about the availability of new Gayn keys or decryption programs.

    🤔 What immediate actions can I take?

    The Gayn ransomware only encrypts the first 150KB of files. Therefore, some media players like Winamp may be able to play MP3 files, but the initial 3-5 seconds (the encrypted portion) will be missing.

    You can try the following to retrieve an original copy of the encrypted file:

    • Redownload files from the internet that were encrypted, as you can obtain the original versions again.
    • Request the original pictures from your family and friends, which they can send back to you.
    • Retrieve photos that you uploaded to social media or stored on cloud services like Carbonite, OneDrive, iDrive, Google Drive, etc.
    • Access attachments in emails you sent or received and saved.
    • Retrieve files from 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 Gayn 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.

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    Brendan Smith
    GAYN Ransomware — How To Restore & Decrypt Files?

    Name: GAYN Virus

    Description: The GAYN Virus belongs to the STOP/DJVU family of ransomware infections. This malicious software encrypts various file types, including videos, photos, and documents, which become identifiable by a distinct ".gayn" extension. As a result, the affected files become inaccessible and unusable.

    Operating System: Windows

    Application Category: Virus

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    User Review
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    References

    1. GAYN Virus sample on VirusTotal
    2. My files are encrypted by ransomware, what should I do now?
    3. About DJVU (STOP) Ransomware.
    4. Trojan Killer Review: https://howtofix.guide/trojan-killer/

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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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