NPSK ransomware: what it is and how to remove it
NPSK ransomware is a cryptovirus that was first spotted at the end of March 2020, attacking users worldwide. Upon infiltration (which is usually executed via software cracks), the malware modifies Windows settings, weakening its defenses, and begins to look for data to encrypt.
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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NPSK ransomware: summary
| Name | NPSK ransomware |
|---|---|
| Type | File locking virus |
| Family | NPSK is a member of the most prominent ransomware family currently – Djvu/STOP |
| Related files | A2AA.tmp.exe |
| Encryption method | All non-system and non-executable files are locked with the help of RSA cipher |
| File extension | Pictures, documents, databases, videos, and other files are marked with .npsk extension. For example, a "picture.jpg" is transformed into a "picture.jpg.npsk" and can no longer be accessed |
| 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 19 more facts
| Random note | _readme.txt – it is placed into each of the folders that contain encrypted data, as well as a desktop |
|---|---|
| Contact | helpmanager@firemail.cc or helpmanager@iran.ir |
| Ransom size | The attackers explain that the price for the decryption tool is $490 in Bitcoin if the contact is established within first 72 hours after infection; later the price doubles to $980 |
| Malware removal | To get rid of malware, employ anti-malware software to scan your computer. If needed, access Safe Mode with networking as explained below |
| Data recovery | Recovering data might be possible with Emsisoft's decryptor if the encryption was performed using an offline ID. Otherwise, options are very limited: Paying threat actors for the tool – not recommended Using third-party software that might in some cases retrieve at least some of the locked files |
| Detection names | No Microsoft detection name is known |
| Encrypted file extension | .npsk |
| Decryptor | No free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates |
| Distribution | Not recorded in the old report |
| Damage | Not recorded in the old report |
| Symptoms | Files renamed with a new extension, a ransom note left in folders and a Windows Security "Threats found" notification |
| Evidence | 5 write-ups by security sites; no sample analysed yet |
| Encrypted files | .npsk |
| Ransom note | _readme.txt |
| Attacker contacts | helpmanager@firemail.cc |
| Free decryptor | No free decryptor is known (checked 6 October 2026) |
| First seen | 23 March 2020 |
| Microsoft Defender name | Trojan:Win32/Racealer.DSK!MTB |
| Facts checked | 6 October 2026 |
NPSK ransomware detection names
If Windows Security shows Trojan:Win32/Racealer.DSK!MTB, it has found NPSK ransomware or a file that belongs to it.
Write the name down before you click Remove: it is the most useful search term later, and you will need it if you report the incident.
A family name in the label is more informative than a heuristic one. Our page on why one threat has many antivirus names lists the common formats and what each part means.
- File extension:
.npsk - Note file:
_readme.txt - Contact:
helpmanager@firemail.cc
From our report of Mar 2020 · not reviewed since
More from our earlier report on NPSK ransomware
- To repair damage done to Windows after malware's termination, use
How NPSK ransomware behaves
From our report of Mar 2020 · not reviewed since
NPSK ransomware is a data locker that stems from Djvu virus family
NPSK ransomware is a cryptovirus that was first spotted at the end of March 2020, attacking users worldwide.
Upon infiltration (which is usually executed via software cracks), the malware modifies Windows settings, weakening its defenses, and begins to look for data to encrypt. With the help of the RSA asymmetric algorithm, the virus appends .npsk extension to each of the files, preventing victims from opening them.
To redeem access to data, users need a particular NPSK ransomware decryptor - it can be obtained from the virus authors. The attackers also inform victims via the _readme.txt note that the tool should be paid for within 72 hours, otherwise the price doubles to $980 in Bitcoin (after the payment, users are advised to send an email to helpmanager@firemail.cc or helpmanager@iran.ir).
However, since the NPSK virus belongs to a well-known malware family, Djvu, there might be a chance of free data recovery with the help of Emsisoft's decryptor if the encryption was performed with an offline ID, so paying cybercriminals is not advisable.
Djvu virus family, which NPSK ransomware belongs to, began its activity back in December 2017, and since then more than 200 variants have been released, each using a different file extension. The frequency of releases grew, and the attackers performed various changes to malware in the meantime.
For example, prior to August 2019, AES cipher was used for the file locking process, which was later replaced by RSA. This happened due to actions of cybersecurity researchers who discovered a way to crack down the malicious actions of malware and released a free decrytpor for the majority of virus versions.
While there is no guaranteed way to retrieve data for those who got infected with variants released past August last year (including the NPSK virus), some victims may be lucky and recover data with another tool from security experts.
However, it only works if NPSK ransomware used and offline ID to lock data, which means that it could not access the remote C&C servers to retrieve a unique key. Additionally, each of suchlike versions can only be decryptable until one of the victims paid the ransom and retrieved the key.
It is important to note that NPSK ransomware removal should be performed after backing up the encrypted files if not backups are available, otherwise, the data might get corrupted. Proceeding with elimination process should be a top priority, as this ransomware family is known to import other malware (such as banking trojans) and modify Windows "hosts" file to prevent users from accessing security related files.
To remove NPSK ransomware from the system, you should employ anti-malware software that can detect and eliminate the threat. Keep in mind that none of the AVs can completely protect your from all new variants of malicious software. Nevertheless, the main executable of NPSK file virus, which is typically named as A2AA.tmp.exe or similar is detected under the following names, according to Virus Total:
As you can see, most of the engines detect the malicious file-based heuristic detection, which means that NPSK ransomware has not been previously captured in the wild. However, this just highlights the importance of anti-malware software - it can prevent the majority of intrusions and save victims from the devastating consequences of ransomware.
- Trojan.GenericKD.42870227
- UDS:DangerousObject.Multi.Generic
- BehavesLike.Win32.Generic.bc
- Trojan.MalPack.GS
- Trojan:Win32/Racealer.DSK!MTB
- TROJ_GEN.R011H0CCM20, etc.
From our report of Mar 2020 · not reviewed since
File encryption process of NPSK ransomware
NPSK ransomware, just as many other file lockers, target Windows users exclusively, as the operating system is the most widespread in the world.
Nevertheless, both of the architectures - 64bit and 32bit are affected.
Once inside the computer, the NPSK virus does not immediately begins the file encryption process. Instead, it weakens computer defenses first in order to prevent victims from achieving easy recovery - it does that with the help of a variety of changes.
For example, it creates multiple new processes and terminates some existing ones, modifies the Windows registry, executes shell commands, starts new services, and much more. To recover revert these changes, we highly suggest scanning the system with after NPSK ransomware removal.
After the preparations are complete, NPSK ransomware begins to look for data to encrypt and targets the most commonly used file extensions like .pdf, .gif, .doc, .mp4, .jpg, .rar, .txt, and many more.
During the encryption process, the virus displays a fake Windows update pop-up in order to stop users from interrupting the process before it is complete. If you can shut down your PC, you can save at least some of your files in some cases.
The following step of NPSK ransomware includes delivering the ransom note _readme.txt so that users would be aware of what happened to their computers and files. The following information is provided inside:
As mentioned before, paying cybercriminals behind NPSK ransomware is not recommended, as they might not deliver the required tool, or it might not work. It is also understandable that some users might not have another choice, despite the risks. Alternatively, you could try using third-party software or a few other methods we list below.
From our report of Mar 2020 · not reviewed since
Software cracks - the easiest way to infect your PC with malware
Tools that are used to bypass the licensing process of an application - the so-called keygens, cracks, or loaders - are often used to deliver malware.
Because of their functionality, security software will usually mark them as malicious regardless if they carry malware or not, so there is no secure way to check whether the crack is safe to use. Besides, perform such activity is illegal in the first place and could result in penalties by law enforcement - another thing to keep in mind.
Therefore, to avoid Djvu ransomware, you should never visit peer-to-peer or warez websites that offer cracked software, as it can be malicious. Instead, if you want to use certain programs, find alternatives that offer free versions, or simply pay for the license - at least you will be guaranteed that the app is secure and fully functional.
You should always backup your data and employ reputable anti-malware software that would protect your machine using a real-time protection module. Nevertheless, this is not enough to protect yourself fully, as you should also:
- never allow a spam email attachment to run a macro ("Allow content") on your machine;
- hover over a link embedded inside a suspicious email to see where it will actually bring you to;
- install the latest security updates for your operating system and all the installed applications;
- use secure passwords for all your accounts and employ two-factor authentication where possible;
- when using Remote Desktop, employ VPN, secure it with a strong password, and never use the default TCP/UDP port;
- employ ad-block, firewall, and other security tools to protect you from harm online.
The NPSK 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-Oc0xgfzC7q
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:
helpmanager@firemail.cc
Reserve e-mail address to contact us:
helpmanager@iran.ir
Your personal ID:
How to remove NPSK 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 NPSK ransomware 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
Unplug the network cable or turn off Wi-Fi, and disconnect USB drives, external disks and network shares, so NPSK ransomware cannot reach more files. Pause OneDrive, Google Drive or Dropbox sync, because synced folders upload the encrypted copies over the good ones.
Leave the PC on but offline while you read the next steps, since a restart can let the ransomware run again. This applies to Windows 11 and Windows 10 alike.
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
Your files now end in
.npskand the instructions are in_readme.txt. Save both to a USB stick, a copy of the note and two small encrypted files, before anything else.On another device, check them with ID Ransomware or Crypto Sheriff: the family name decides which decryptor, if any, can help. Keep the note's ID and contact line for your report.
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
Our last check found that for NPSK ransomware, no free decryptor is known (checked 6 October 2026). Look again yourself in the No More Ransom list and the free decryptor pages of Emsisoft, Avast and Kaspersky, which add new families every year.
A decryptor needs the ransomware gone first, or it encrypts the files again. Keep at least one copy of the encrypted files on an external drive, even if no tool works yet.
Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 4: Remove the ransomware before you restore or decrypt
Removing NPSK ransomware does not bring the files back, but it has to come first. Start with Defender's Full scan, then the offline scan from the same Scan options page, which checks the disk before Windows loads.
If the scan cannot start, use Safe Mode with Networking. Delete the ransom notes only after you have saved a copy, because removal tools sometimes leave them behind on Windows 11 and 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
Windows keeps shadow copies for restore points and backups, and some ransomware fails to delete them.
vssadmin list shadowsin an administrator Command Prompt tells you at once whether any exist.If they do, right-click the folder that held your files, open Properties > Previous Versions, select a version from before the attack, and click Open to check it before you Restore or copy the files out. Windows 11 and Windows 10 both have the tab.
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
A backup made before the attack is the surest way back. Connect it only once the PC is clean, then restore from File History, Windows Backup, OneDrive's Restore your OneDrive or your own external copies.
Without a backup, try file recovery: the originals that NPSK ransomware deleted may still be on the disk until something overwrites them. Install nothing new on the drive you want to recover from on the Windows 11 or Windows 10 PC.
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 Mar 2020 · not reviewed since
Remove NPSK ransomware from your system
As previously mentioned, while NPSK ransomware removal is very important to achieve as soon as possible due to its secondary functionality, you should not do it immediately if you have no backups prepared. First, copy the locked data over to a USB Flash or virtual storage like Google Drive to ensure that it will not get damaged during the further actions that you have to proceed with.
Once you have backups, you can remove NPSK ransomware with the help of anti-malware software. If in some cases, the malware is tampering with your security app, you can access Safe Mode with Networking as explained below and perform a full scan from there. Additionally, you should also go to the following location and delete the "hosts" file to regain access to all the websites:
It is important to note that, if Emsisoft's decryptor does not currently work, but you have an offline ID, it should become functional in the future for the NPSK virus as well.
[GI=method-1]In case your anti-malware software fails to work correctly, go to Safe Mode as follows:
[GI=method-2]In some cases, you can get rid of NPSK ransomware with the help of System Restore:
Data is not immediately erased from your hard drive, and, as long that space is not overwritten with other information, it can still be retrieved.
Windows Previous Versions feature might be helpful
This method will only work if you had System Restore enabled prior to the infection.
Make use of ShadowExplorer
In case NPSK ransomware failed to remove Shadow Volume Copies, ShadowExplorer should be able to recover all the data.
Use Emsisoft's decryptor
If your files were encrypted with an offline ID, you should use Emsisoft's decryption tool to recover files for free. Remember, if the tool does not work on an offline ID, you need to wait sometime before somebody pays the ransom and contacts Emsisoft to deliver the key.
Additionally, you can also employ a paid service from Dr.Web - you can contact the staff here.
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.
Backups: the 3-2-1 rule
Keep three copies of files that matter, on two kinds of storage, with one copy offline or off-site.
A disk that stays plugged in is reached by malware like NPSK ransomware together with the PC; one you connect only for the backup is not.
On Windows 11, File History keeps versions on an external drive, and OneDrive keeps earlier versions of synced files. Before restoring anything, make sure the PC no longer shows files that end in .npsk and no longer open.
Setting it up step by step: 3-2-1 backups on Windows 11 and 10.
Protect your privacy - employ a VPN
There are several ways how to make your online time more private - you can access an incognito tab.
However, there is no secret that even in this mode, you are tracked for advertising purposes. There is a way to add an extra layer of protection and create a completely anonymous web browsing practice with the help of VPN. This software reroutes traffic through different servers, thus leaving your IP address and geolocation in disguise.
Besides, it is based on a strict no-log policy, meaning that no data will be recorded, leaked, and available for both first and third parties. The combination of a secure web browser and VPN will let you browse the Internet without a feeling of being spied or targeted by criminals.
No backups? No problem. Use a data recovery tool
If you wonder how data loss can occur, you should not look any further for answers - human errors, malware attacks, hardware failures, power cuts, natural disasters, or even simple negligence.
In some cases, lost files are extremely important, and many straight out panic when such an unfortunate course of events happen. Due to this, you should always ensure that you prepare proper data backups on a regular basis.
If you were caught by surprise and did not have any backups to restore your files from, not everything is lost. is one of the leading file recovery solutions you can find on the market - it is likely to restore even lost emails or data located on an external device.
Questions about NPSK ransomware
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.
Did NPSK ransomware steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by NPSK ransomware, but the only confirmed sign is files that end in .npsk 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.
How do I open .npsk files?
You cannot open them by renaming or by choosing another program. The .npsk ending shows that NPSK ransomware 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 NPSK ransomware. Store the encrypted files on an external disk until then.
Is there a free NPSK ransomware decryptor?
We last checked on 6 October 2026, and for NPSK ransomware 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 "NPSK ransomware 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.
How did NPSK ransomware get on my computer?
The way NPSK ransomware 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 .npsk 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 NPSK ransomware 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 .npsk from the file names?
You can try it on a copy, but for real ransomware it will not help. The .npsk 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 NPSK ransomware?
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 NPSK ransomware, 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
- Comparitech: What is RSA encryption and how does it work? (read October 6, 2026)
- Emsisoft: Emsisoft releases new decryptor for STOP Djvu ransomware (read October 6, 2026)
- Virus Total: A2AA.tmp.exe (read October 6, 2026)
- Wikipedia: Heuristic analysis (read October 6, 2026)
- CISA: StopRansomware (read October 6, 2026)