How to protect a computer from rasnomware like Masok?

Also Known As: Masok virus
Distribution: Moderate
Damage level: Severe

Masok ransomware removal instructions

What is Masok?

Masok is a ransomware-type program which belongs to the Djvu family. The person who discovered is Michael Gillespie. Cyber criminals who designed Masok spread it with a purpose to make money from people who cannot access their files because this ransomware has encrypted them. In order to be able to decrypt their files, victims are forced to buy a decryption tool and key. Masok modifies the extension of every encrypted file by changing it to ".masok". For example, it changes "1.jpg" to "1.jpg.masok" and so on. Instructions on how to pay the ransom (and contact Masok developers) are provided in the "_readme.txt" text file.

To contact cyber criminals who designed Masok, victims have to write them an email to gorentos@bitmessage.ch or gorentos2@firemail.cc, or contact them via @datarestore account on Telegram. As stated in the ransom note ("_readme.txt"), they should do it in the first 72 hours after encryption, because then they will get a 50% discount and will not have to pay the full price ($980). Additionally, it is possible to decrypt one encrypted file for free, it can be done by sending it to cyber criminals via one the provided emails or Telegram. In order to encrypt other data victims have to buy a decryption tool and key. The biggest problem with having a computer infected with ransomware is that locked files usually can be decrypted with tools that only cyber criminals have. However, we do not recommend to pay ransomware developers, quite often they do not send their victims the promised tools/keys. In this case we recommend to try to unlock files with an online decryption tool, however, it works only if during the encryption a computer was not connected to the Internet or/and remote server controlled by cyber criminals was not responding. One more way to get the files back is to restore them from an existing backup.

Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:

Masok decrypt instructions

Typically, ransomware-type programs lock files using strong encryption algorithms and create/display ransom notes. The most common (and main) differences between these programs usually are: the price of a decryption tool/key and algorithm (symmetric or asymmetric) that is used to encrypt files. Unfortunately, most of the times people who have their computers infected with ransomware do not have many options, they can either pay cyber criminals (which is not recommended) or restore files using backup. That is why it is very important to always have data backed up and store it on a remote server or unplugged storage device. Examples of other ransomware-type programs are Prandel, Zatrov and Q1G.

How did ransomware infect my computer?

One of the most common ways to proliferate ransomware (or other malware) is to send people emails that contain malicious attachments. These attachments are designed to download and install high-risk malicious software. However, they can do it only if recipients open them. Some examples of files that cyber criminals attach are Microsoft Office and PDF documents, archive files (like RAR, ZIP), executable files (.exe), JavaScript files and so on. Another way to spread malware is through other malicious programs that are called Trojans. Programs of this type are designed to cause chain infections: once installed, they download and install other dangerous software. Untrustworthy, unofficial websites, freeware download and free file hosting pages, Peer-to-Peer networks (torrent clients, eMule and so on) and other similar sources can be used as channels to spread computer infections too. People who use them to download files risk to download infected files that are disguised as normal and harmless. When opened, they install malicious programs. Fake software updaters, if used, infect systems when they download and install malware instead of updates, or they exploit bugs, flaws of outdated software that is installed on a computer. Software 'cracking' tools can cause serious damage too. As a rule, these tools are used by people who want to activate paid (licensed) software or operating system for free. However, they often end up having their computers infected because people who develop these tools often use them to spread malware.

Threat Summary:
Name Masok virus
Threat Type Ransomware, Crypto Virus, Files locker
Detection Names Avast (Win32:PWSX-gen [Trj]), BitDefender (Gen:Variant.Ser.Jaik.565), ESET-NOD32 (A Variant Of Win32/Kryptik.GVGH), Kaspersky (Trojan-Ransom.Win32.Stop.cn), Full List Of Detections (VirusTotal)
Encrypted Files Extension .masok
Ransom Demanding Message _readme.txt
Ransom Amount $980/$490
Cyber Criminal Contact gorentos@bitmessage.ch, gorentos2@firemail.cc or @datarestore (Telegram).
Symptoms Can't open files stored on your computer, previously functional files now have a different extension, for example my.docx.locked. A ransom demanding message is displayed on your desktop. Cyber criminals are asking to pay a ransom (usually in bitcoins) to unlock your files.
Additional Information This malware is designed to show fake Windows Update window, modify Windows "hosts" file (to prevent users from accessing cyber security websites) and inject AZORult trojan into the system.
Distribution methods Infected email attachments (macros), torrent websites, malicious ads, unofficial activation and updating tools.
Damage All files are encrypted and cannot be opened without paying a ransom. Additional password stealing trojans and malware infections can be installed together with a ransomware infection.
Removal

To eliminate Masok virus our malware researchers recommend scanning your computer with Spyhunter.
▼ Download Spyhunter
Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Spyhunter.

How to protect yourself from ransomware infections?

We strongly recommend not to use various software cracking tools, it is not legal to use them and quite often cyber criminals use them to spread malware. Do not open attachments (or web links) that are included in irrelevant emails. Typically, these emails are sent from unknown, suspicious addresses. Furthermore, update installed programs with tools or functions that are provided by official developers. Do not download programs or files from questionable (unofficial) pages or through third party tools. The safest way to achieve it is to use official pages and direct download links. And finally, regularly scan the operating system with a reputable anti-virus or anti-spyware suite. If there is no such software installed on a computer, we recommend to install it as soon as possible. If your computer is already infected with Masok, we recommend running a scan with Spyhunter for Windows to automatically eliminate this ransomware.

Text presented in Masok ransomware's text file ("_readme.txt"):

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:
-

Screenshot of files encrypted by Masok (".masok" extension):

Files encrypted by Masok

Malware researcher Michael Gillespie has developed a decryption tool that might restore your data if it was encrypted using an "offline key". As we've already mentioned, each victim gets a unique decryption key and all of them are stored in remote servers controlled by cyber criminals. These are categorized as "online keys". However, there are cases when the infected machine has no Internet connection or the server is timing out/not responding. If that is the case, Masok will use an "offline encryption key", which is hard-coded. Now it is worth mentioning that cyber criminals change offline keys every now and again. This is being done to prevent multiple encryptions with the same key. Meanwhile, Michael Gillespie continually gathers offline keys and updates the decrypter. However, the chances of successful decryption are still very low, since only a very small portion of "offline keys" has been gathered. You can download the decrypter by clicking this link (note that the download link remains the same, despite the fact that decrypter is being continually updated). Your files will be restored only if the list of gathered keys will include the one that was used to encrypt your data.

Screenshot of STOP/Djvu decrypter by Michael Gillespie:

STOP/Djvu ransomware decrypter by Michael Gillespie

As with most of ransomware from Djvu family, Masok also displays a fake Windows update pop-up during the encryption:

Djvu ransomware family fake update

IMPORTANT NOTE! - Aside from encrypting data, ransomware-type infections from Djvu malware family also installs a trojan-type virus called AZORult, which is designed to steal various account credentials. Moreover, this malware family is designed to add a number of entries to the Windows hosts file. The entries contain URLs of various websites, most of which are related to malware removal. This is carried out with the intention of making users unable to access malware security websites and seek help. Our website (PCrisk.com) is also on the list. Removing these entries, however, is simple - you can find detailed instructions in this article (note that, although the steps are shown in the Windows 10 environment, the process is virtually identical on all versions of the Microsoft Windows operating system).

Screenshot of websites added to Windows hosts file:

Tro Ransomware adding websites to Windows Hosts file

Masok ransomware removal:

Instant automatic removal of Masok virus: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Spyhunter is a professional automatic malware removal tool that is recommended to get rid of Masok virus. Download it by clicking the button below:
▼ DOWNLOAD Spyhunter By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Spyhunter.

Quick menu:

Step 1

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup. Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings". Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Windows 8 Safe Mode with networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options". In the advanced options menu select "Startup Settings" and click on the "Restart" button. In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

windows 10 safe mode with networking

Video showing how to start Windows 10 in "Safe Mode with Networking":

Step 2

Log in to the account infected with the Masok virus. Start your Internet browser and download a legitimate anti-spyware program. Update the anti-spyware software and start a full system scan. Remove all entries detected.

If you cannot start your computer in Safe Mode with Networking, try performing a System Restore.

Video showing how to remove ransomware virus using "Safe Mode with Command Prompt" and "System Restore":

1. During your computer start process, press the F8 key on your keyboard multiple times until the Windows Advanced Options menu appears, and then select Safe Mode with Command Prompt from the list and press ENTER.

Boot your computer in Safe Mode with Command Prompt

2. When Command Prompt mode loads, enter the following line: cd restore and press ENTER.

system restore using command prompt type cd restore

3. Next, type this line: rstrui.exe and press ENTER.

system restore using command prompt rstrui.exe

4. In the opened window, click "Next".

restore system files and settings

5. Select one of the available Restore Points and click "Next" (this will restore your computer system to an earlier time and date, prior to the Masok ransomware virus infiltrating your PC).

select a restore point

6. In the opened window, click "Yes".

run system restore

7. After restoring your computer to a previous date, download and scan your PC with recommended malware removal software to eliminate any remaining Masok ransomware files.

To restore individual files encrypted by this ransomware, try using Windows Previous Versions feature. This method is only effective if the System Restore function was enabled on an infected operating system. Note that some variants of Masok are known to remove Shadow Volume Copies of the files, so this method may not work on all computers.

To restore a file, right-click over it, go into Properties, and select the Previous Versions tab. If the relevant file has a Restore Point, select it and click the "Restore" button.

Restoring files encrypted by CryptoDefense

If you cannot start your computer in Safe Mode with Networking (or with Command Prompt), boot your computer using a rescue disk. Some variants of ransomware disable Safe Mode making its removal complicated. For this step, you require access to another computer.

To regain control of the files encrypted by Masok, you can also try using a program called Shadow Explorer. More information on how to use this program is available here.

shadow explorer screenshot

To protect your computer from file encryption ransomware such as this, use reputable antivirus and anti-spyware programs. As an extra protection method, you can use programs called HitmanPro.Alert and EasySync CryptoMonitor, which artificially implant group policy objects into the registry to block rogue programs such as Masok ransomware.

Note that Windows 10 Fall Creators Update includes "Controlled Folder Access" feature that blocks ransomware attempts to encrypt your files. By default this feature automatically protects files stored in Documents, Pictures, Videos, Music, Favorites as well as Desktop folders.

Controll Folder Access

Windows 10 users should install this update to protect their data from ransomware attacks. Here's more information on how to get this update and add additional protection layer from ransomware infections.

HitmanPro.Alert CryptoGuard - detects encryption of files and neutralises any attempts without need for user-intervention:

hitmanproalert ransomware prevention application

Malwarebytes Anti-Ransomware Beta uses advanced proactive technology that monitors ransomware activity and terminates it immediately - before reaching users' files:

malwarebytes anti-ransomware

  • The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups. More information on online backup solutions and data recovery software Here.

Other tools known to remove Masok ransomware:

About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for pcrisk.com since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

PCrisk security portal is brought by a company RCS LT. Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.

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Malware activity

Global virus and spyware activity level today:

Medium threat activity
Medium

Increased attack rate of infections detected within the last 24 hours.

QR Code
Masok virus QR code
A QR code (Quick Response Code) is a machine-readable code which stores URLs and other information. This code can be read using a camera on a smartphone or a tablet. Scan this QR code to have an easy access removal guide of Masok virus on your mobile device.
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Platform: Windows

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