Derp ransomware: what it is and how to remove it
Derp ransomware, discovered by Michael Gillespie, is one of the latest variants of the Djvu ransomware family that promotes file decryption by using a unique algorithm.
Emsisoft reported that they have released the STOP/Djvu decryption software that works for Djvu ransomware variants that have been released earlier than August 2019, so Derp virus still remains undecryptable as it uses a different decryption tool than its previous ancestors that were released before August.
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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Derp ransomware: summary
| Name | Derp ransomware |
|---|---|
| Type | Ransomware |
| Family | Djvu ransomware (STOP virus) |
| Version number | Research shows that this malware is the 176th variant of the Djvu category |
| Appendix | Once files are locked with a unique cipher, they end up with the .derp appendix |
| Ransom message | The malware displays the _readme.txt message where crooks urge for $490 as a starter price if the money is transferred in 3 days and $980 if the victim goes over the time limit |
| 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 17 more facts
| File location | Malicious executables might be found in the %LocalAppData% or %AppData% directories. Additionally, the Windows Task Manager and Registry might also be filled with suspicious entries/files |
|---|---|
| Additional malware | STOP ransomware variants (this includes Derp virus) are known for distributing AZORult trojan |
| Discoverer | Michael Gillespie has announced his findings on Twitter social network |
| Detection names | No Microsoft detection name is known |
| Contact | gorentos@bitmessage.ch, gerentoshelp@firemail.cc, gorentoshelp@firemail.cc |
| Encrypted file extension | .derp |
| 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 and a ransom note left in folders |
| Evidence | 5 write-ups by security sites; no sample analysed yet |
| Encrypted files | .derp |
| Ransom note | _readme.txt |
| Attacker contacts | gorentos@bitmessage.ch |
| Free decryptor | No free decryptor is known (checked 6 October 2026) |
| First seen | 25 October 2019 |
| Facts checked | 6 October 2026 |
- File extension:
.derp - Note file:
_readme.txt - Contact:
gorentos@bitmessage.ch
From our report of Oct 2019 · not reviewed since
More from our earlier report on Derp ransomware
- Afterward, try using to scan the computer for damage
How Derp ransomware behaves
From our report of Oct 2019 · not reviewed since
Derp ransomware - the 176th version of the Djvu ransomware that is currently undecryptable
Derp ransomware, discovered by Michael Gillespie, is one of the latest variants of the Djvu ransomware family that promotes file decryption by using a unique algorithm.
Emsisoft reported that they have released the STOP/Djvu decryption software that works for Djvu ransomware variants that have been released earlier than August 2019, so Derp virus still remains undecryptable as it uses a different decryption tool than its previous ancestors that were released before August.
However, the activity principle is the same - alterings of the Windows Registry/Task Manager, encryption by adding a specific appendix (.derp in this case), ransom demands from $490 to $980 via the _readme.txt message.
During installation, Derp ransomware will supposedly drop a malicious executable in the %LocalAppData% or %AppData% folder that is responsible for finding decryptable files on your Windows computer. Additionally, the malware can delete the Windows hosts file to prevent the user from accessing security-related forums and networks.
Nevertheless, you will supposedly find malicious entries and files in the Task Manager and Windows Registry added by Derp ransomware. This way the malware ensures that it will be automatically booted within every computer startup process. Additionally, some dropped entries might allow the malware to avoid being detected by security software.
Furthermore, Derp ransomware might target Shadow Copies of the encrypted tada in order to harden the decryption process for the users themselves. For this purpose, the malware launches a module that runs specific PowerShell commands and permanently deletes the Shadow Volume Copies from the computer system.
If you have taken a good look to the _readme.txt ransom note, you will see that Derp ransomware developers are trying to threaten you that there is no other option of recovering your files instead of paying the demanded price:
The criminals urge for $490 if the ransom price is transferred in a three-day time period. However, if the victim is too late and decides to pay after 72 hours, he has to now transfer a doubled price. Derp ransomware urges a pretty big price here and our experts say that it is not worth paying such amount of money while there is a big risk of scamming.
The crooks also provide gorentos@bitmessage.ch, gorentoshelp@firemail.cc email addresses as a way to contact them. We suggest avoiding any contact possible and going straight for Derp ransomware removal. If you get scammed, it would be almost impossible to recover your money as hackers often urge prices in Bitcoin or another cryptocurrency that guarantees full anonymity.
One more reason why you should remove Derp ransomware ASAP is that the malware can distribute the AZORult Trojan horse. All STOP ransomware viruses might be capable of injecting this malicious threat for money swindling, private information stealing, or other illegitimate and damaging purposes.
After Derp ransomware is gone, you can try fixing the damage with software such as . However, note that the tool does not decrypt data. For that, travel to the end of the article and choose a method to try. Also, you can purchase DrWeb's Rescue Pack for $150 that includes decryption software that might be capable of recovering some data and also two full years of antimalware protection.
From our report of Oct 2019 · not reviewed since
Vulnerable RDP configuration allows malware installation
Security experts from LosVirus.es state that RDPs which include weak passwords or no password security at all are a very nice target for bad actors.
These people hack the RDP (for example, TCP port 3389) and connect to the targeted computer system by remote technique.
Even though this ransomware distribution method is a very popular one, there are other techniques that are not less popular. Criminals often drop questionable email messages to the user's inbox or spam sections. Sometimes, the crooks pretend to be from official shipping companies such as FedEx/DHL, banking firms, or healthcare organizations in order to give the look of a trustworthy email.
Afterward, users are encouraged to click on a particular hyperlink or open an infectious attachment where ransomware is hiding. Nevertheless, this still is not it. Hackers are capable of distributing malware via many other different sources! Unsecured p2p networks, outdated software, exploit kits, fake Flash Player updates, infectious downloading links and ads, gambling networks, porn sources - all these places are potential ransomware holders.
The Derp 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-sTWdbjk1AY
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:
gerentoshelp@firemail.cc
Your personal ID:
How to remove Derp 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 Derp 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
Derp ransomware 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.derpto 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 Derp ransomware, 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 Derp ransomware 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 Oct 2019 · not reviewed since
Avoiding ransomware and preventing system damage
Once you have learned about ransomware distribution techniques, it is about time to learn how to avoid these dangerous cyber threats.
First of all, you should purchase reliable antivirus protection. You can find various user and expert reviews in forums and security pages where you might be able to choose the right tool for you. When you have the program, do not forget to update it when official upgrades are released.
Continuously, learn how to manage your email box. Delete all messages that fall to your spam section but also be careful with letters that appear in the inbox.
Evaluate the expectancy of the email, check out the sender, and search the entire content for grammar/style mistakes. If you have a questionable feeling of the email, better delete it as any reputable company would manage to contact you in other ways, e.g. mobile phone.
Furthermore, avoid downloading movies and video clips from sources such as The Pirate Bay, eMule, and other torrenting networks as these websites provide software cracks that might be filled with dangerous viruses, including ransomware. Also, do not perform any software updates you are not aware of, keep all of your programs regularly upgraded, and keep a fair distance from all questionable online sources.
From our report of Oct 2019 · not reviewed since
Derp ransomware removal guidelines
Derp ransomware removal needs to be performed as soon as you find .derp files on your computer system.
Eliminating the virus on your own is not a possibility here. Keep in mind that reputable antimalware software is necessary if you are looking forward to a safety elimination process.
After you remove Derp ransomware, you can try downloading one of these tools: , , or . This software might help you to fix the damage that has been brought by the malware.
When Derp virus is gone, you should start taking care of your future data. Purchase and USB flash drive and keep your data or at least copies of important files stored on the remote device in case of a repeated malware attack in the future.
[GI=method-1]Boot your Windows computer to Safe Mode with Networking. Focus on the process with the help of these instructing guidelines.
[GI=method-2]Launch System Restore on your machine to reverse all bogus changes. Use the below-provided instructions if you need some help with this procedure.
Use this software to restore some of the files and documents that were locked by the ransomware virus.
Use Windows Previous Versions feature for data recovery tasks.
If you have enabled System Restore in the past, you can try employing this technique for file restoring purposes.
Try using Shadow Explorer for data restore:
You can use this method for the recovery of your files, however, it might not work if the ransomware virus eliminated Shadow Copies of the encrypted files.
Sadly, the official decryptor for this ransomware version has not been developed yet.
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 Derp 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 .derp and no longer open.
Setting it up step by step: 3-2-1 backups on Windows 11 and 10.
Do not let government spy on you
The government has many issues in regards to tracking users' data and spying on citizens, so you should take this into consideration and learn more about shady information gathering practices.
Avoid any unwanted government tracking or spying by going totally anonymous on the internet.
You can choose a different location when you go online and access any material you want without particular content restrictions. You can easily enjoy internet connection without any risks of being hacked by using VPN.
Control the information that can be accessed by government any other unwanted party and surf online without being spied on. Even if you are not involved in illegal activities or trust your selection of services, platforms, be suspicious for your own security and take precautionary measures by using the VPN service.
Backup files for the later use, in case of the malware attack
Computer users can suffer from data losses due to cyber infections or their own faulty doings.
Ransomware can encrypt and hold files hostage, while unforeseen power cuts might cause a loss of important documents. If you have proper up-to-date backups, you can easily recover after such an incident and get back to work. It is also equally important to update backups on a regular basis so that the newest information remains intact - you can set this process to be performed automatically.
When you have the previous version of every important document or project you can avoid frustration and breakdowns. It comes in handy when malware strikes out of nowhere. Use for the data restoration process.
Questions about Derp ransomware
Is there a decryptor for .derp files?
That depends on the family behind the .derp extension, which this guide cannot confirm yet from the reports alone. Check No More Ransom and ID Ransomware with your ransom note and one encrypted file; they list families with free tools.
If none exists today, keep the encrypted files and a copy of the note on a separate drive, because decryptors are sometimes published months later after flaws are found or servers are seized. Never buy a decryptor from a website that is not the security company that made it.
Should I pay the ransom in _readme.txt?
Not before you have tried everything else. Identify the family from _readme.txt and one encrypted file, check No More Ransom for a free decryptor, and look for clean copies in OneDrive, backups and Previous Versions.
Paying funds further attacks, may be illegal if the group is sanctioned, and is no promise of a working key: many victims get partial or broken decryption. If you consider paying for business-critical data, involve the police and a professional incident responder first, and never pay through intermediaries who promise their own decryption.
How do I open .derp files?
You cannot open them by renaming or by choosing another program. The .derp ending shows that Derp 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 Derp ransomware. Store the encrypted files on an external disk until then.
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 Derp ransomware get on my computer?
The way Derp 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 .derp 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.
Did Derp ransomware steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by Derp ransomware, but the only confirmed sign is files that end in .derp 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 Derp 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 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 .derp spread to my other drives?
It can. Ransomware encrypts every drive and network share it can reach while it runs, so external disks, USB sticks and shared folders connected during the attack may also have files ending in .derp. Disconnect everything now, then check each device from a clean computer.
Do not plug a backup drive into the infected PC until the ransomware has been removed with an offline scan. Cloud folders such as OneDrive sync the encrypted versions, but they keep earlier versions you can usually restore.
Will Fortect remove Derp 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 Derp 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
- Twitter: #STOP #Djvu #Ransomware (read October 6, 2026)
- Emsisoft: Emsisoft Decryptor for STOP Djvu (read October 6, 2026)
- LosVirus: LosVirus.es (read October 6, 2026)
- Wikipedia: Remote Desktop Protocol (read October 6, 2026)
- CISA: StopRansomware (read October 6, 2026)