Masok ransomware: what it is and how to remove it
Masok is a notorious file-encrypting malware that belongs to the ransomware family. It differs from viruses of this kind as it can not only make your files useless but can also bring the AZORult Trojan horse to the infected Windows system.
Facts checked October 6, 2026. Removal steps tested on Windows 11 (26H2) and checked against Microsoft's and the browser makers' current documentation. Sections marked as our earlier report are the original text: they describe the threat as it was then and have not been reviewed since. The 2026 status, the removal steps and the questions are current.
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Masok ransomware: summary
| Distribution | You can experience malicious activity from this virus after opening a malicious email, hyperlink, executable, etc. |
|---|---|
| Name | Masok |
| Type | Ransomware virus |
| Family | Djvu/STOP ransomware |
| Extension | .masok |
| Ransom note | _readme.txt |
| Removal | Scan the PC with security software to find and remove the malware and anything installed with it. Fortect scans Windows for malware and repairs the system files and settings it damaged. Remove it nowTo use the full-featured product, you have to purchase a license for Fortect. The scan is free. |
Show 15 more facts
| Price | Starting from $490 if contact is made in 72 hours and ending up with $980 if the victims fail to make communication during the three day time period |
|---|---|
| Other malware | This ransomware might be capable of injecting the AZORult just like other versions of STOP virus |
| Data recovery | If you have been looking for ways to restore encrypted data, take a look at the methods that are provided at the end of this article |
| Detection names | No Microsoft detection name is known |
| Contact | gorentos@bitmessage.ch, gorentos2@firemail.cc, @datarestore |
| Encrypted file extension | .masok |
| Decryptor | No free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates |
| Damage | Not recorded in the old report |
| Symptoms | Files renamed with a new extension and a ransom note left in folders |
| Evidence | 5 write-ups by security sites; no sample analysed yet |
| Encrypted files | .masok |
| Attacker contacts | gorentos@bitmessage.ch |
| Free decryptor | No free decryptor is known (checked 6 October 2026) |
| First seen | 11 November 2019 |
| Facts checked | 6 October 2026 |
- File extension:
.masok - Note file:
_readme.txt - Contact:
gorentos@bitmessage.ch
From our report of Nov 2019 · not reviewed since
More from our earlier report on Masok
- Use for a full system check-up.
- Afterward, terminate the ransomware permanently
How Masok ransomware behaves
From our report of Nov 2019 · not reviewed since
Masok - a cyber threat hailing from the infamous Djvu family and spreading another destructive virus AZORult
Masok is a notorious file-encrypting malware that belongs to the ransomware family.
It differs from viruses of this kind as it can not only make your files useless but can also bring the AZORult Trojan horse to the infected Windows system. Once there, the trojan can start gathering personal information and send it to the remote server.
The roots of Masok ransomware are hailing from the Djvu and STOP families. However, once the virus appears on the targeted machine, it drops its executables in the Task Manager and Registry, encrypts files, marks them with the .masok extension, and urges to pay from $490 to $980 for their recovery. The ransom note which provides all information about the file recovery is saved in the _readme.txt document.
Masok ransomware and similar cyber threats are commonly distributed to gain revenue. Criminals tend to scam their victims by scaring that the only way to recover encrypted data is by paying a huge ransom. They try to convince people that once the demanded price is transferred, they will immediately receive the decryption software and successfully restore blocked files:
The cybercriminals provide three ways to contact them via gorentos@bitmessage.ch or gorentos2@firemail.cc email addresses and @datarestore telegram account. However, there is always a huge risk to pay these crybercriminals while trying to recover .masok files.
What you can do is remove Masok ransomware from the system after scanning it with antimalware. Once you get rid of all malicious components and processes, you can continue with some data recovery techniques that are placed at the end of the article and might help you to bring some files/documents back to their previous states.
Also, you should opt for Masok removal right after spotting it on your machine because this ransomware virus might carry other malicious payloads with itself. As it is known that STOP ransomware and its variants can infect the system with the AZORult Trojan horse. If this task is implemented, there is a big risk of losing private data and becoming a victim of identity theft.
Masok ransomware can be spotted from the .masok extension and the _readme.txt message that appears on the system without being expected. Antivirus tools have been detecting the malware by using these detection names:
It is more than clear that Masok ransomware might bring big harm to your computer system and important files. The encryption process is the moment when your files are locked and the only guaranteed way to recover them is if you have their backups.
However, even if you don't have backups saved in a remote location, there still is no need of paying for the crooks. Remove the malware without wasting your time and them wait until the Stop Decrypter gets updated.
- Gen:Variant.Ser.Jaik.565 (B) (Emsisoft).
- Trojan.MulDrop9.44966 (DrWeb).
- Trojan.TR/AD.InstaBot.awy (F-secure).
From our report of Nov 2019 · not reviewed since
Distribution tactics used by ransomware developers
According to experts from NoVirus.uk, there are many unsecured sources from which ransomware and other malware might reach your computer system.
However, the most popular places where you might ransomware are odd websites such as email spam, p2p networks, gambling, gaming, and porn web pages. Read the steps below and know how to protect yourself:
Using the combination of manual and automatical protection measures is the best option for preventing secret malware infiltration and keeping your computer, software, personal information, and various files safe from corruption/theft.
- Manage your email. Erase all messages that have fallen to your spam section and carefully manage all emails in your inbox sector. This means checking the sender, spotting possible grammar mistakes, and scanning attachments with AV.
- Keep a distance from secondary networks. Pages that are supported by third-parties are usually sources that lack protection and allow criminals to inject malicious objects into unprotected hyperlinks and similar locations.
- Download reputable antimalware. If you do not have a trustworthy antivirus program installed on your computer system, you will supposedly run into big trouble, sooner or later. Make sure to purchase a tool that includes various protective features and keep it always updated.
The Masok ransomware note
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-2P5WrE5b9f
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:
gorentos@bitmessage.ch
Reserve e-mail address to contact us:
gorentos2@firemail.cc
Our Telegram account:
@datarestore
Mark Data Restore
Your personal ID:
-
How to remove Masok ransomware
Tools you'll need
All of these are free except where noted. Download them on a clean device if the infected PC is offline.
- A USB stick: to keep the ransom note, two or three encrypted files and screenshots off the infected PC.
- Microsoft Defender Offline: built into Windows 11 and Windows 10; scans before Windows starts, so running malware cannot hide.
- Microsoft Safety Scanner: a second, portable scanner with current signatures; each download works for 10 days.
- ID Ransomware: identifies the family from the note and one encrypted file and says whether a decryptor exists.
- No More Ransom: the free decryptors from police and security companies; check it again every few months.
- Fortect (optional): scans Windows for malware and repairs the system files and settings it damaged. The free scan is in the box above.
How to remove Masok and get your files back
Work in this order.
Disconnecting comes first, removal comes before any restore, and nothing here asks you to contact the attackers.
Step 1: Disconnect the PC and unplug backup drives
Masok encrypts everything it can reach, including drives and shares you connect later. Cut the network first: cable out, or Wi-Fi off from the taskbar.
Then unplug every USB stick and backup disk and pause cloud sync, so the encrypted versions do not replace your online copies. Do not reconnect any of them until the ransomware is removed from the Windows 11 or Windows 10 PC.
Windows 11: turn off Wi-Fi to take the PC offline. Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 2: Save the ransom note and confirm the family
Copy
_readme.txtand one or two files ending in.masokto a USB stick, and leave the originals where they are.From another device, upload the note and a sample file to ID Ransomware or No More Ransom's Crypto Sheriff, which name the family from the note, the extension and the file structure.
Write down the contact address and your personal ID from the note, because a decryptor or the police may ask for them.
Warning: Never contact the attackers from the infected Windows 11 or Windows 10 PC.
Windows 11: the ransom note and encrypted files to copy for identification. Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 3: Check for a free decryptor
For Masok, no free decryptor is known (checked 6 October 2026). Search the family name in the No More Ransom decryption tools list and in the free decryptors of Emsisoft, Avast and Kaspersky, because new tools appear years after an attack.
Important: Keep the encrypted files even if nothing works today, and do not pay before every free option is ruled out: payment does not guarantee a working key.
Decryptors run on Windows 11 and Windows 10, but only after the ransomware itself is removed.
Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 4: Remove the ransomware before you restore or decrypt
Restoring or decrypting files while Masok still runs lets it encrypt them again. Run a Full scan in Windows Security > Virus & threat protection > Scan options, then the Microsoft Defender Antivirus (offline scan).
If the ransomware blocks Windows Security, start Safe Mode with Networking and scan from there. Some families install a password stealer as well, so let both scans finish on Windows 11 or Windows 10.
Windows 11: Windows Security > Virus & threat protection > Scan options. Full procedure with screenshots: Run a Microsoft Defender Offline scan
Step 5: Look for shadow copies of the files
Open Command Prompt as administrator and run
vssadmin list shadows. If it lists copies dated before the attack, right-click a folder with encrypted files in File Explorer, choose Properties > Previous Versions, and open or restore a version from before that date.ShadowExplorer, a free tool, shows the same copies when the tab is empty or hidden. Most current families delete shadow copies, so an empty list is normal, but the check takes two minutes on Windows 11 or Windows 10.
Windows 11: vssadmin list shadows shows whether shadow copies exist. Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 6: Restore the files from a backup or recover deleted originals
Restore from an external backup, File History or OneDrive's version history, choosing a date before the attack. Connect the backup drive only after the scans are clean, or the ransomware encrypts it too.
If there is no backup, file recovery software can sometimes find the deleted originals, because some ransomware writes an encrypted copy and deletes the original file.
Stop writing to the drive and try recovery on Windows 11 or Windows 10 before new files overwrite the space.
Full procedure with screenshots: Recover deleted files (Recycle Bin, backups, OneDrive) On uGetFix
Instructions for each browser and system
The detailed steps for every browser and system this guide covers. Open the one you use.
Manual removal using Safe Mode
Important! →
Manual removal guide might be too complicated for regular computer users. It requires advanced IT knowledge to be performed correctly (if vital system files are removed or damaged, it might result in full Windows compromise), and it also might take hours to complete. Therefore, we highly advise using the automatic method provided above instead.
Step 1. Access Safe Mode with Networking
Manual malware removal should be best performed in the Safe Mode environment.
Windows 7 / Vista / XP
- Click Start > Shutdown > Restart > OK.
- When your computer becomes active, start pressing F8 button (if that does not work, try F2, F12, Del, etc. - it all depends on your motherboard model) multiple times until you see the Advanced Boot Options window.
- Select Safe Mode with Networking from the list.
Windows 10 / Windows 8
- Right-click on Start button and select Settings.
- Scroll down to pick Update & Security.
- On the left side of the window, pick Recovery.
- Now scroll down to find Advanced Startup section.
- Click Restart now.
- Select Troubleshoot.
- Go to Advanced options.
- Select Startup Settings.
- Press Restart.
- Now press 5 or click 5) Enable Safe Mode with Networking.
Step 2. Shut down suspicious processes
Windows Task Manager is a useful tool that shows all the processes running in the background. If malware is running a process, you need to shut it down:
- Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
- Click on More details.
- Scroll down to Background processes section, and look for anything suspicious.
- Right-click and select Open file location.
- Go back to the process, right-click and pick End Task.
- Delete the contents of the malicious folder.
Step 3. Check program Startup
- Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
- Go to Startup tab.
- Right-click on the suspicious program and pick Disable.
Step 4. Delete virus files
Malware-related files can be found in various places within your computer. Here are instructions that could help you find them:
- Type in Disk Cleanup in Windows search and press Enter.
- Select the drive you want to clean (C: is your main drive by default and is likely to be the one that has malicious files in).
- Scroll through the Files to delete list and select the following:
Temporary Internet Files
Downloads
Recycle Bin
Temporary files - Pick Clean up system files.
- You can also look for other malicious files hidden in the following folders (type these entries in Windows Search and press Enter):
%AppData%
%LocalAppData%
%ProgramData%
%WinDir%
After you are finished, reboot the PC in normal mode.
From our report of Nov 2019 · not reviewed since
Masok ransomware virus elimination guidelines for non-skilled and advanced users
Masok ransomware removal is a process that can be completed by both less-experienced and highly-skilled users.
However, no manual actions should be taken by any kind of person as the entire system can be put at risk. The automatical technique is the only one that should be used here.
For that, you need to employ reputable software for Masok removal together with all infected files. Besides, performing a full system check-up is also a necessary step to take as the malware can modify system components. For that, use .
To doublecheck the system for ransomware, use , or . Once the software provides you with the results, you will know what kind of actions to take towards the elimination process. After you remove Masok ransomware properly, take a look at the below-provided data recovery software that might allow you to restore some files.
[GI=method-1]Reboot to Safe Mode with Networking to stop malicious processes that have been recently provoked by Masok ransomware virus.
[GI=method-2]Use System Restore to reverse some changes initiated by the malware and get a chance to launch anti-virus. Follow the steps below to prevent anything malicious from running.
If you try using this third-party tool exactly as shown in the instructing guide, you might succeed and recover some of your documents and files that have been touched by Masok ransomware virus.
Windows Previous Versions feature is suitable for file restoring tasks:
Using this software might allow you to restore some of your data that was encrypted by the malware. However, ensure that you have booted your computer to System Restore earlier.
Try the Shadow Explorer tool for reversing files back to their primary states:
If the ransomware virus did not touch Shadow Volume Copies of your encrypted files, using this software gives you the possibility of restoring them to the same position as they were before the malware attack.
STOP ransomware decrypter hasn't been updated yet
Even though no official decryptor has been released directly to unlock .masok files, you can download and give a try to the STOP ransomware decryption software.
Report it and recover your files
Report it
Report the attack even if you do not expect the files back: insurers and banks ask for the report number, and police use the contacts in the note to link cases.
- United States
- FBI IC3 · FTC ReportFraud
- United Kingdom
- Report Fraud (formerly Action Fraud) · NCSC
- Australia
- ReportCyber (ASD)
- EU countries
- Europol: national reporting sites
Give the victim ID, the note and the date the files were encrypted. A business that holds personal data may also have to notify its data protection authority, in the EU within 72 hours.
Make the next attack harmless
Masok could only hurt the files that had no second copy, and the signs (files that end in .masok and no longer open) showed exactly which ones those were.
The 3-2-1 rule fixes that:
- three copies
- two media
- one disconnected
A practical version for a home PC: OneDrive or another cloud backup with version history, plus an external disk that you plug in once a week for File History and then unplug. Test a restore now and then by opening a few files from the backup on another device.
Details, schedules and what not to back up are in our 3-2-1 backup guide for Windows.
Choose a proper web browser and improve your safety with a VPN tool
Online spying has got momentum in recent years and people are getting more and more interested in how to protect their privacy online.
One of the basic means to add a layer of security - choose the most private and secure web browser. Although web browsers can't grant full privacy protection and security, some of them are much better at sandboxing, HTTPS upgrading, active content blocking, tracking blocking, phishing protection, and similar privacy-oriented features.
However, if you want true anonymity, we suggest you employ a powerful VPN - it can encrypt all the traffic that comes and goes out of your computer, preventing tracking completely.
Lost your files? Use data recovery software
While some files located on any computer are replaceable or useless, others can be extremely valuable.
Family photos, work documents, school projects - these are types of files that we don't want to lose. Unfortunately, there are many ways how unexpected data loss can occur:
- power cuts
- Blue Screen of Death errors
- hardware failures
- crypto-malware attack
- even accidental deletion
To ensure that all the files remain intact, you should prepare regular data backups. You can choose cloud-based or physical copies you could restore from later in case of a disaster. If your backups were lost as well or you never bothered to prepare any, can be your only hope to retrieve your invaluable files.
Questions about Masok ransomware
How do I open .masok files?
You cannot open them by renaming or by choosing another program. The .masok ending shows that Masok encrypted the content, and only the matching key can reverse it. Renaming a file back to .docx or .jpg changes nothing except the icon, and it can confuse a future decryptor, so leave the names as they are.
To get the content back, use a backup, an unencrypted copy elsewhere, or a decryptor listed on No More Ransom if one exists for Masok. Store the encrypted files on an external disk until then.
Should I pay the ransom?
We advise against it, and so do the FBI, Europol and national cyber agencies. Payment does not guarantee a working tool: some attackers never reply, some tools damage files, and some variants have no decryptor at all. Paying also funds further attacks and can make you a target again.
Before considering payment, try every recovery option in this guide and report the attack. Companies must involve their legal adviser and insurer, because payments to sanctioned groups can be illegal. If files are truly irreplaceable, store the encrypted copies and wait; decryptors sometimes appear later.
How did Masok get on my computer?
The way Masok spreads has not been documented yet, so look at your own recent activity. On home PCs, ransomware most often comes with cracked programs, game cheats, key generators and fake updates, or with an e-mail attachment that was opened. On business networks, attackers usually log in through Remote Desktop with a stolen or guessed password.
Think back to what was downloaded or installed in the days before files that end in .masok and no longer open, and check the Downloads folder and Installed apps sorted by date. Keep anything suspicious for your report, but do not run it again.
Is there a free Masok decryptor?
We last checked on 6 October 2026, and for Masok no free decryptor is known. We check No More Ransom, which collects free tools from police and security companies, and the decryptor pages of the major antivirus vendors. A working decryptor exists only when the encryption has a flaw or the keys were leaked or seized.
Ignore sites and videos that offer a "Masok decryptor" for download or for a fee: these are usually scams or malware. Real decryptors are free and come from known security companies or law enforcement. Keep the encrypted files in case a tool appears later.
Can a data-recovery company decrypt my files for a fee?
Only if a decryptor already exists or the company pays the attackers for you. Some "ransomware recovery" services advertise that they can decrypt families with no known flaw; in practice they negotiate with the attackers and add their own fee. Others use the same free tools listed on No More Ransom.
Before you hire anyone, ask in writing how they will recover the files, whether they will contact the attackers and what happens if they fail. A legitimate service answers clearly. If a free decryptor exists for your family, you can run it yourself.
Did Masok steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by Masok, but the only confirmed sign is files that end in .masok and no longer open, which says nothing about what happened before. Many current ransomware attacks copy files or run a password stealer first, so it is wise to act as if they did.
From a clean device, change the passwords that were saved in the browsers on this PC, starting with e-mail and banking, sign out of all sessions and turn on two-step verification. Watch bank statements and account activity for the next few weeks.
Is Masok the same as other ransomware with a similar name?
Not necessarily. Ransomware names come from the file extension, the note or a word in the code, so unrelated families often end up with similar names, and one family can appear under several names. The difference matters: a decryptor or advice for one family does not fit another and can damage files.
Compare the ending added to your files and the exact name of the note with the summary table at the top of this guide, then upload the note and one encrypted file to ID Ransomware from a clean device. If the result names another family, follow the guide for that family instead.
Can I just remove .masok from the file names?
You can try it on a copy, but for real ransomware it will not help. The .masok extension is only a label; the file content has been scrambled with a key the attackers hold.
If a renamed copy opens normally, the malware only renamed files, which happens with some fake ransomware, and you can rename the rest back. If it does not open, leave the files as they are. Renaming encrypted files can confuse a decryptor later, so always work on copies.
Can I delete _readme.txt?
Yes, the note itself is harmless text and deleting it does not affect your files. Keep at least one copy first, outside the infected PC. _readme.txt contains your personal ID and the attackers' contact details, which identification services use to tell which family encrypted your files, and which a decryptor may need later.
Police reports also ask for it. Once you have saved a copy, you can remove the notes from every folder after the ransomware program has been removed and your files are restored or backed up.
Will Fortect remove Masok?
Fortect scans Windows for malware and unwanted programs and repairs the system files and settings they change, and its free scan shows what it finds on your PC before you decide anything.
For Masok, follow the plan above as well: the browser steps take back permissions and settings that no scanner treats as a threat, and uninstalling the program that brought it removes the source.
Run Microsoft Defender's full scan and, if anything was found, its offline scan as a second opinion. If the symptoms are gone after the plan and both scans are clean, there is nothing more to do.
Sources
- Virus Total: 52 engines detected this file (read October 6, 2026)
- Wikipedia: Encryption (read October 6, 2026)
- CISA: StopRansomware (read October 6, 2026)
- No More Ransom (read October 6, 2026)
- FTC: How to recognize, remove and avoid malware (read October 6, 2026)