Written by Brendan Smith
Npsk is a DJVU family of ransomware-type infections1. The virus encrypts important personal files (video, photos, documents). Encrypted files can be tracked by specific “.npsk” extension. So, you can’t open them at all.
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In this guide I will try to help you remove the Npsk virus without any payment. As a bonus, I will assist you in decoding your encrypted files.

What is “Npsk”?

Npsk can be correctly identify as a ransomware infection.
Ransomware is a specific kind of virus that crypts your documents and then forces you to pay to restore them. Note that DJVU (aka STOP) ransomware family was first revealed and discovered by virus analyst Michael Gillespie2.

Npsk is similar to other representatives of the same family: OPQZ, Remk, Foop, Lokd. It crypts all common file types. Hence, users cannot use the your documents . Npsk adds its particular “.npsk” extension into all files. For instance, the file “video.avi”, will be changed into “video.avi.npsk”. As soon as the encryption is accomplished, Npsk drops a special file “_readme.txt” and drop it into all folders that contain the modified files.

Here is a details for the Npsk infection:
Ransomware family3DJVU/STOP4 ransomware
Ransomware note_readme.txt
RansomFrom $490 to $980 (in Bitcoins),
Detection5Win32/Packed.CAB.AE, Win32/Injector.ELCU, Trojan.MalPack.DLF
SymptomsYour files (photos, videos, documents) have a .npsk extension and you can’t open it
Fix ToolSee If Your System Has Been Affected by .npsk file virus

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

Npsk virus message

The scary alert demanding from users to pay the ransom to decrypt the compromised data contains these frustrating warnings

The cryptography algorithm used by Npsk is AES-256. So, if your documents got encrypted with a specific decryption key, which is unique and there are no other copies. The sad reality is that it is impossible to restore the information without the unique key available.

In case if Npsk worked in online mode, you can’t gain access to the AES-256 key. It is stored on a distant server owned by the frauds who promote the Npsk virus.

Yes, that could be a solution to turn your Internet connection off and use Decryption tool. But if you wont delete the ransomware, he can encrypt your data again, as soon as your PC is back online.

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 (, or via Telegram.

UPD. 28.03.2020. Some users reported about changed payment requirements : frauds asking about 1500-1600$ for decryption key. There are still a lot of causes of “old” price list, but it seems that fraudsters are forcing their victims to pay more or pay fast.

It’s important to notice that user’s PC will be running well before files encrypting, without any allusion of the ransomware onboard. And even after encrypting process started, you won’t notice any significant changes. It’s making .npsk ransomware and all others ransomwares very base and difficult to detect, because majority of users starting AV-scans only after significant troubles caused by different malware.

Another feature of all ransomwares is a different encrypting time. It differs from ransomware to ransomware, and depends only on ransomware developer’s wish. For Npsk ransomware regular encryption time is about 30 minutes : at first it encrypts files that was been used just now, then all other files without any strict logic.

Do not pay for Npsk!

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

_readme.txt file also indicates that the computer owners must get in touch with the Npsk representatives during 72 hours starting from the moment of files where encrypted. On the condition of getting in touch within 72 hours, users will be granted a 50% rebate, thus the ransom amount will be minimized down to $490). Nonetheless, stay away from paying the ransom!

I certainly advise that you do not contact these crooks and do not pay. The one of the most real working solution to recover the lost data – just using the available backups, or use Decrypter tool.

Contacting ransomware distributors via e-mail is bad idea not only because it’s useless. They can force you to pay them for decryption key, and even threaten you to delete all your data. But anyway, they will likely add your e-mail to their database and make profit via it’s selling to another fraudsters, or just to someone who will send you annoying ads of some sort.

The peculiarity of all such viruses apply a similar set of actions for generating the unique decryption key to recover the ciphered data.

Thus, unless the ransomware is still under the stage of development or possesses some hard-to-track flaws, manually recovering the ciphered data is a thing you can’t perform. The only solution to prevent the loss of your valuable data is to regularly make backups of your crucial files.

Note that even if you do maintain such backups regularly, they ought to be put into a specific location without loitering, not being connected to your main workstation.

Even more, if you have already done a backup with unactive Npsk ransomware onboard, you will get a bad surprise when using that backup for your system restoration after ransomware attack. Even worse – at the moment your PC getting back online, the Npsk ransomware will get an encryption command again, so your backup won’t have any effect.

For instance, the backup may be kept on the USB flash drive or some alternative external hard drive storage. Optionally, you may refer to the help of online (cloud) information storage.

Needless to mention, when you maintain your backup data on your common device, it may be similarly ciphered as well as other data.

For this reason, locating the backup on your main computer is surely not a wise idea.

Another bad idea can be using a decrypter tool without removing a ransomware. Well, you decrypted your files, but what could stop Npsk ransomware from encrypting your files again? So, if you want to completely deal with ransomware, you need to combine Decryption tool and Ransomware remover tool.

How I was infected?

Npsk has a various methods to built into your system. But it doesn’t really matter what concrete way had place in your case.

Npsk ransomware attack

Npsk attack following a successful phishing attempt.

Nevertheless, these are the common leaks through which it may be injected into your PC:

  • hidden installation along with other apps, especially the utilities that work as freeware or shareware;
  • dubious link in spam emails leading to the Npsk installer
  • online free hosting resources;
  • using illegal peer-to-peer (P2P) resources for downloading pirated software.

There were cases when the Npsk virus was disguised as some legitimate tool, for example, in the messages demanding to initiate some unwanted software or browser updates. This is typically the way how some online frauds aim to force you into installing the Npsk ransomware manually, by actually making you directly participate in this process.

Surely, the bogus update alert will not indicate that you are going to inject the Npsk ransomware. This installation will be concealed under some alert mentioning that allegedly you should update Adobe Flash Player or some other dubious program whatsoever.

Of course, the cracked apps represent the damage too. Using P2P is both illegal and may result in the injection of serious malware, including the Npsk ransomware.

To sum up, what can you do to avoid the injection of the Npsk ransomware into your device? Even though there is no 100% guarantee to prevent your PC from getting damaged, there are certain tips I want to give you to prevent the Npsk penetration. You must be cautious while installing free software today.

Make sure you always read what the installers offer in addition to the main free program. Stay away from opening dubious email attachments. Do not open files from the unknown addressees. Of course, your current security program must be always updated.

The malware does not speak openly about itself. It will not be mentioned in the list of your available programs. However, it will be masked under some malicious process running regularly in the background, starting from the moment when you launch your computer.

Another pecular detail of Npsk ransomware that it is usually distributed in bundle with another malware. Majority of ransomwares have no patterns of malware to be distributed with, but most often it is adware, browser hijackers, keyloggers or so, that’s why its quite hard to detect ransomware injection in your computer in pack with another viruses.

UPD 23.03.2020. A lot of users reporting about Npsk ransomware distribution on popular torrent-trackers like 1337x and RARBG. This ransomware been added in a plenty of seedings, so a big number of users been infected. The most popular types of files that was been shared and infected are music, anime and cinema.

UPD. 31.03.2020. Another wave of ransomware injection is detected through RARBG torrent-tracker. Users are complaining of Npsk ransomware inside of different file types, but the most often complains was on Tresto user’s seedings. His profile is quite old, but last time he was sharing only games and old (1990’s-2000’s) films.

UPD. 02.04.2020. An information appeared that Npsk ransomware was been distributed with Restoro, program that wants to be an antimalware, but really it is a PUP – potentially unwanted program, that finds unexisting threats on user’s PC and then offers to remove it for money. Users, who got Restoro on their PC, complaining that they have been attacked by Npsk ransomware shortly after Restoro removing.

The message by the Npsk ransomware states the following frustrating information:


Don't worry, you can return all your files!
All your files like photos, databases, documents and other important are encrypted with the strongest encryption and unique key.
The only method of recovering files is to purchase a decrypt tool and unique key for you.
This software will decrypt all your encrypted files.
What guarantees you have?
You can send one of your encrypted file from your PC and we decrypt it for free.
But we can decrypt only 1 file for free. File must not contain valuable information.
You can get and look video overview decrypt tool:
Price of private key and decrypt software is $980.
Discount 50% available if you contact us first 72 hours, that's price for you is $490.
Please note that you'll never restore your data without payment.
Check your e-mail "Spam" or "Junk" folder if you don't get answer more than 6 hours.

To get this software you need write on our e-mail:

Reserve e-mail address to contact us:

Your personal ID:

Some users are reporting about another “price range”: fraudsters want the same 490$ if user pays in 72 hrs, but after this term their requirement increases to 1200$ (somewhere even up to 1500$). That’s looking like an attempt to force users to pay faster in order to not to be billed on triple sum.

The image below gives a clear vision of how the files with “.npsk” extension look like:

Npsk Virus - crypted .npsk files

Example of crypted .npsk files

How to remove Npsk virus?

In addition to encode a victim’s files, the Npsk virus has also started to install the Azorult Spyware on computer to steal account credentials, cryptocurrency wallets, desktop files, and more.
Reasons why I would recommend GridinSoft6

The is an excellent way to deal with recognizing and removing threats – using Gridinsoft Anti-Malware. This program will scan your PC, find and neutralize all suspicious processes7.

Download Removal Tool.

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

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 system.

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

Press “Install” button.

GridinSoft Anti-Malware Install

Once installed, Anti-Malware will automatically run.

GridinSoft Anti-Malware Splash-Screen

Wait for the Anti-Malware scan to complete.

GridinSoft Anti-Malware will automatically start scanning your computer for Npsk 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.

GridinSoft Anti-Malware Scanning

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.

GridinSoft Anti-Malware Scan Result

How to decrypt .npsk files?

Restore solution for big “.npsk files

Try removing .npsk extension on a few BIG files and opening them. Either the Npsk infection 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 Remk, Foop, Lokd, etc.

As a result of the changes made by the criminals, STOPDecrypter is no longer supported. Tt has been removed and replaced with the Emsisoft Decryptor for STOP Djvu Ransomware developed by Emsisoft and Michael Gillespie.

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

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

Select folders for decryption.

Based on the default settings, the decryptor will automatically populate the available locations 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.

Click on the “Decrypt” button.

As soon as yo 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 forum messages if you need to do so.

Frequently Asked Questions

How can I open “.npsk” files?

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

npsk files contain important information. How can I decrypt them urgently?

If your data remained in the .npsk files are very valuable, then most likely you made a backup copy.
If not, then you can try to restore them through the system function – Restore Point.
All other methods will require patience.

You have advised using GridinSoft Anti-Malware to remove NPSK. Does this mean that the program will delete my encrypted files?

Of course not. Your encrypted files do not pose a threat to the computer. What happened has already happened.

You need GridinSoft Anti-Malware to remove active system infections. The virus that encrypted your files is most likely still active and periodically,
runs a test for the ability to encrypt even more files. Also, these viruses install keyloggers and backdoors for further malicious actions
(for example theft of passwords, credit cards) often.

Decrytor 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 Npsk ransomware, and decryption keys have not yet been released. Follow the news on our website.
We will keep you posted on when new Npsk keys or new decryption programs appear.

What can I do right now?

If your computer is infected with ransomware, I recommend that you contact the following government fraud and scam sites to report this attack:

Video Guide

It’s my favorite video tutorial: How to use GridinSoft Anti-Malware and Emsisoft Decryptor for fix ransomware infections.

If the guide doesn’t help you to remove Npsk infection, please download the GridinSoft Anti-Malware that I recommended. Also, you can always ask me in the comments for getting help. Good luck!

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  1. Ransomware-type infection:
  2. Twitter:
  3. My files are encrypted by ransomware, what should I do now?
  4. About DJVU (STOP) Ransomware.
  5. Encyclopedia of threats.
  6. GridinSoft Anti-Malware Review from HowToFix site:
  7. More information about GridinSoft products:

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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