.onion file extension virus: what it is and how to remove it
.onion file virus is a malicious computer program that can be associated with a couple of ransomware families - Dharma, Amnesia, and Cry128 (CryptON). The ransomware was dubbed as Onion file virus due to the extension it adds to encrypted data.
Facts checked October 7, 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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.onion file extension virus: summary
| Detection names | No Microsoft detection name is known |
|---|---|
| Ransom note | _DECRYPT_MY_FILES.txt; the text of the note is not in our records |
| Contact | volantem_diem@aol.com.onion, Gladius_Adeptus@aol.com |
| Encrypted file extension | Not recorded in our earlier report |
| Decryptor | No free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates |
| Distribution | Not recorded in the old report |
| 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 9 more facts
| Damage | Not recorded in the old report |
|---|---|
| Name | .onion file extension virus |
| Type | File-encrypting ransomware |
| Symptoms | A ransom note left in folders |
| Evidence | 7 write-ups by security sites; details still limited |
| Attacker contacts | volantem_diem@aol.com.onion |
| Free decryptor | No free decryptor is known (checked 7 October 2026) |
| First seen | 23 August 2017 |
| Facts checked | 7 October 2026 |
Traces of .onion file extension virus you can check
- Note file:
_DECRYPT_MY_FILES.txt - Contact:
volantem_diem@aol.com.onion
How .onion file extension virus behaves
From our report of Aug 2017 · not reviewed since
.onion file extension virus wreaks havoc on compromised computers
.onion file virus is a malicious computer program that can be associated with a couple of ransomware families - Dharma, Amnesia, and Cry128 (CryptON).
The ransomware was dubbed as Onion file virus due to the extension it adds to encrypted data. The extension might also contain criminals' email address or victim's ID. The aim of the virus is to encrypt files on the target system to make them inaccessible and then demand a ransom.
This ransomware family has been spotted in November 2016 and has been updated several times since then. Malware researchers have recently spotted this cyber infection and found connections to several ransomware families. Below, you can see the list of viruses that use the .onion extension as a file marker.
The virus is known for corrupting various types of files; however, not all attempts to take data to hostage were successful. Some versions of the Dharma is decryptable, and users can free their files without paying the ransom.
This new parasite is known for adding .onion file extension to the corrupted files. It's still unknown whether victims can restore encoded data or not. New versions of the ransomware often are improved. Thus, authors may have fixed some flaws and developed a stronger virus.
However, if you ever encounter this pest, you should not focus on data recovery first. The most important task is to remove .onion from the computer in order to protect your device and personal data.
The purpose of all file-encrypting viruses is the same - to swindle the money from computer users. Thus, .onion malware is also used as a blackmailing tool to continue the illegal work of the predecessors. Crooks are willing to get your money for the possibility to use a decryption software and recover your files.
Lesvirus.fr team states that no matter how much Bitcoins you are ready to pay, this deal may not end up as you planned. They may take your money and leave you without promised decryptor because they may not have it or they may not have any intentions to keep their word .
Bear in mind that previous versions of Dharma are decryptable, so, chances to get back your files for free are high.
- Cry128 ransomware virus. It is a version of CryptON virus that marks files with id-_[qg6m5wo7h3id55ym.onion.to]. file extensions. The virus may use .onion or .onion.to_ extension to add at the end of the encrypted file name. Usually, this virus calls its ransom notes as _DECRYPT_MY_FILES.txt or -DECRYPT-MY-FILES.txt.
- Amnesia ransomware virus. The malware completely distorts the file names and marks them with onion extension as well. To provide a ransom-demanding statement, the ransomware creates HOW TO RECOVER ENCRYPTED FILES.TXT document.
- CrySiS/Dharma ransomware virus. The virus appends id-[victim's ID].volantem_diem@aol.com.onion, .id- .[Gladius_Adeptus@aol.com].onion file extension to encrypted files. The ransom note is usually hidden in Info.hta file.
From our report of Aug 2017 · not reviewed since
Ways to avoid ransomware attack
The variant of Dharma is suspected of spreading similarly as its predecessors - via malicious email attachments.
Crooks might pretend to be representatives from various institutions, organizations or companies and find numerous reasons to convince people to open the attached document. It might be hard to recognize a hoax at first glance because criminals might falsify credentials or signature.
However, if you suddenly receive an email that asks to check details in the statement or other provided document and send it back immediately, you should suspect that something is not right here. Look for grammar mistakes, check sender's email address, and be critical - do you expect to get this kind of email? If not, delete it from your inbox immediately.
Clicking on the attached document might cause .onion file virus or other malware attacks. This ransomware distribution technique is popular and widely used among hackers. Thus, if you want to protect your data, you should not take harsh actions in your inbox and backup your files regularly.
The .onion file extension virus ransom note
The note is called _DECRYPT_MY_FILES.txt.
We did not record the full text of the ransom note in our report.
How to remove .onion file extension virus
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 .onion file extension virus 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 .onion file extension virus 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 identify the family
The name of the family decides whether a free decryptor can help. Copy the ransom note and two small encrypted files to a USB stick, and check them on another device with ID Ransomware or Crypto Sheriff.
Note the extension added to the files, the contact address and the victim ID shown in the note. Keep the originals on the Windows 11 or Windows 10 PC untouched.
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 .onion file extension virus, no free decryptor is known (checked 7 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 .onion file extension virus 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 .onion file extension virus 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 Aug 2017 · not reviewed since
Remove .onion file virus and try available data recovery options
Getting infected with ransomware requires acting fast.
Do not consider taking a shady deal to obtain a decryption software from cyber criminals for few Bitcoins. It may not end up good, and you might become just another sponsor for the cyber crimes.
Thus, without thinking too much, you need to remove .onion file virus using a reputable software. File-encrypting viruses are dangerous and complicated; thus, you need to rely on professional security tools. We suggest using , or . These programs are capable of detecting malicious entries and deleting them from the system.
However, .onion removal may not be easy and smooth. These cyber infections are often designed to block antivirus or anti-malware programs. However, you can disable the virus by rebooting PC to the Safe Mode with Networking and then access necessary software.
[GI=method-1]If you cannot install or access antivirus program, you need to disable the virus. Follow the steps below and then run your preferred to tool to remove the virus automatically.
[GI=method-2]If the previous method did not help to access security software, try this one:
This professional tool helps to recover corrupted, deleted and encrypted files. It has already helped numerous victims of ransomware, so you should give it a try as well.
Use Windows Previous Versions feature to copy individual files
If System Restore function has been activated before ransomware attack, follow the steps below and copy previously saved versions of the encrypted files.
Try ShadowExplorer to restore files encrypted by .onion file extension virus
If malware hasn't deleted Shadow Volume Copies of the targeted files, this recovery method may help you. Follow the steps below to restore onion files.
We are sorry, but there is no way to decrypt Onion virus at the moment. You can check for updates on NoMoreRansom.org site.
Report it and recover your files
Report it
Report the attack even if you do not expect the files back: insurers and banks ask for the report number, and police use the contacts in the note to link cases.
- United States
- FBI IC3 · FTC ReportFraud
- United Kingdom
- Report Fraud (formerly Action Fraud) · NCSC
- Australia
- ReportCyber (ASD)
- EU countries
- Europol: national reporting sites
Give the victim ID, the note and the date the files were encrypted. A business that holds personal data may also have to notify its data protection authority, in the EU within 72 hours.
Make the next attack harmless
.onion file extension virus could only hurt the files that had no second copy, and the signs (ransom notes called _DECRYPT_MY_FILES.txt in every folder) showed exactly which ones those were.
The 3-2-1 rule fixes that:
- three copies
- two media
- one disconnected
A practical version for a home PC: OneDrive or another cloud backup with version history, plus an external disk that you plug in once a week for File History and then unplug. Test a restore now and then by opening a few files from the backup on another device.
Details, schedules and what not to back up are in our 3-2-1 backup guide for Windows.
Choose a proper web browser and improve your safety with a VPN tool
Online spying has got momentum in recent years and people are getting more and more interested in how to protect their privacy online.
One of the basic means to add a layer of security - choose the most private and secure web browser. Although web browsers can't grant full privacy protection and security, some of them are much better at sandboxing, HTTPS upgrading, active content blocking, tracking blocking, phishing protection, and similar privacy-oriented features.
However, if you want true anonymity, we suggest you employ a powerful VPN - it can encrypt all the traffic that comes and goes out of your computer, preventing tracking completely.
Lost your files? Use data recovery software
While some files located on any computer are replaceable or useless, others can be extremely valuable.
Family photos, work documents, school projects - these are types of files that we don't want to lose. Unfortunately, there are many ways how unexpected data loss can occur:
- power cuts
- Blue Screen of Death errors
- hardware failures
- crypto-malware attack
- even accidental deletion
To ensure that all the files remain intact, you should prepare regular data backups. You can choose cloud-based or physical copies you could restore from later in case of a disaster. If your backups were lost as well or you never bothered to prepare any, can be your only hope to retrieve your invaluable files.
Questions about .onion file extension virus
Is there a free .onion file extension virus decryptor?
We last checked on 7 October 2026, and for .onion file extension virus 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 ".onion file extension virus 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.
Are ransomware recovery services legitimate?
Some are, but read the offer carefully. Genuine data-recovery firms recover deleted originals from disks or rebuild damaged files, and they say so. Others promise to "decrypt any ransomware" for a fixed price, which is impossible without the key; they quietly pay the attackers and keep a margin, sometimes without telling the victim.
Be especially careful with services that contact you after you post about the attack online. Ask for references, a written method and a no-result-no-fee clause, and check the free tools on No More Ransom first.
Did .onion file extension virus steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by .onion file extension virus, but the only confirmed sign is ransom notes called _DECRYPT_MY_FILES.txt in every folder, 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 did .onion file extension virus get on my computer?
The way .onion file extension virus 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 ransom notes called _DECRYPT_MY_FILES.txt in every folder, and check the Downloads folder and Installed apps sorted by date. Keep anything suspicious for your report, but do not run it again.
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.
Is .onion file extension virus 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 _DECRYPT_MY_FILES.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. _DECRYPT_MY_FILES.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.
Can I get my files back without paying after _DECRYPT_MY_FILES.txt appeared?
Sometimes. Free decryptors exist for a number of families, especially older ones or those with flaws in their encryption. Other routes are copies the ransomware missed:
- OneDrive version history
- File History
- a backup drive that was disconnected
- email attachments
- phone photos
Shadow copies are often deleted, but it is worth checking. Identify the family from _DECRYPT_MY_FILES.txt first, because that tells you which of these routes is realistic. Keep encrypted files even if nothing works now; decryptors are sometimes released months later.
How do I open my .docx, .jpg and other files locked by .onion file extension?
You cannot open locked files normally while they stay encrypted, and renaming them will not help. Our earlier report did not record the extension that .onion file extension adds, so check one locked file name and the ransom note for it.
No free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates. Do not rename the files, change the extension or edit them, because that can make recovery harder. Copy the locked files to an external drive before you clean the system, so a decryptor released later still has them.
Will Fortect remove .onion file extension virus?
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 .onion file extension virus, 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
- LesVirus: LesVirus (read October 7, 2026)
- Kaspersky blog: Hospital learns the hard way why you don't pay ransomware crooks (read October 7, 2026)
- CISA: StopRansomware (read October 7, 2026)
- No More Ransom (read October 7, 2026)
- FTC: How to recognize, remove and avoid malware (read October 7, 2026)
