Thanatos ransomware: what it is and how to remove it
Thanatos is a ransomware virus that belongs to the crypto family. It is written in Thanatos.pdb programming language and mostly spreads via malicious spam email attachments.
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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Thanatos ransomware: summary
| Distribution | Spam, illegal software, fake popups |
|---|---|
| Name | Thanatos |
| Type | Ransomware |
| File extension | .THANATOS |
| Ransom note | README.txt; the text is quoted in full below |
| Contact email | c-m58@mail.ru |
| 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 13 more facts
| Amount of ransom | 0.01 BTC |
|---|---|
| Decryption | Download free Thanatos decryption tool from GitHub |
| Detection names | No Microsoft detection name is known |
| Encrypted file extension | .thanatos |
| Decryptor | No free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates |
| 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 | .thanatos |
| Attacker contacts | c-m58@mail.ru |
| Free decryptor | No free decryptor is known (checked 7 October 2026) |
| First seen | 27 June 2018 |
| Facts checked | 7 October 2026 |
- File extension:
.thanatos - Note file:
README.txt - Contact:
c-m58@mail.ru
From our report of Jun 2018 · not reviewed since
More from our earlier report on Thanatos
- Since Thanatos does not modify the file creation dates on encrypted files, the key search space can be further reduced to approximately the number of milliseconds within the 24-hour period leading up to the infection.
- At an average of 100,000 brute-force attempts per second (which was the baseline in a virtual machine used for testing), it would take roughly 14 minutes to successfully recover the encryption key in these conditions.
- Send $200 to one of these wallets: BTC: 1HvEZ1jZ7BWgBYPxqCvWtKja3a9hsNa9Eh ETH: 0x92420e4D96E5A2EbC617f1225E92cA82E24B03ef BCH: qzuexhcqmkzcdazq6jjk69hkhgnme25c35s9tamz6f 2.
The Thanatos ransomware note
Thanatos v1.1
Your files was encrypted. To decrypt your files,
follow next steps:
1. Send $200 to one of these wallets:
BTC: [payment address omitted]
ETH: [payment address omitted]
BCH: qzuexhcqmkzcdazq6jjk69hkhgnme25c35s9tamz6f
2. Send your TXID and your MachineID to mail
E-Mail: thanatos1.1@yandex.com
Machine ID: {ID HERE}
—————————————————
Do not waste your time, files can only be
decrypted by our decode tool.
How to remove Thanatos 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 Thanatos 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 Thanatos 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
.thanatosand the instructions are inREADME.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 Thanatos, 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 Thanatos 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 Thanatos 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 Jun 2018 · not reviewed since
Thanatos - a decryptable ransomware virus which is actively spreading around
Thanatos is a ransomware virus that belongs to the crypto family.
It is written in Thanatos.pdb programming language and mostly spreads via malicious spam email attachments. As soon as the infiltration succeeds, ransomware activates the payload and encrypts all files using AES algorithm to make files on the affected computer unavailable.
To distinguish locked files, the virus appends .THANATOS file extension to the targeted files and drops "the README.txt" where victims are demanded to contact hackers via c-m58@mail.ru email and pay 0.01 BTC for a decryption key.
Thanatos first showed up in February 2018 and soon came back with an updated version later that month. According to researchers, ransomware authors did not have the decryptor themselves, thus, paying the ransom was out of the question.
In late June 2018, security experts from Cisco managed to crack the malicious code and create a free ThanatosDecryptor. Researchers managed to find a vulnerability in the encryption procedure used by the virus.
The trick lied in how the virus determines the key for each of the encrypted files. It is based on the time (in milliseconds) since Windows was last launched. Using Windows Event Logs, security experts managed to reverse-engineer the key. Cisco researchers explained the following:
What makes Thanatos exclusive from the rest of ransomware viruses is the types of cryptocurrency that it accepts. The victim is allowed to transfer the ransom in Ethereum, BitCoin, and BitCoin Cash. Thus, it's the first crypto-ransomware that register payments via BitCoin Cash (BCH) wallet.
Right after the Thanatos ransomware attack, the victim will no longer be able to open documents, images, multimedia, databases, and other files stored on the machine. However, he or she should see "the README.txt" file, which stands for a ransom note in each folder containing locked files. The file provides the contact information (c-m58@mail.ru or thanatos1.1@yandex.com) and crypto-currency wallet addresses:
It seems that developers of the Thanatos ransomware improved it soon after the original version started attacking victims because initially crooks provided c-m58@mail.ru as a contact email and accepted the 0.01 BTC ransom. However, the version of the virus did not change. Experts detect the same v1.1 circulating, but beware that it may provide diverse information.
The ransom note tells that after the payment is transferred, the users should receive a decryptor by email. The truth is that there's no Thanatos decryptor at all - neither paid nor free. According to ransomware analysts, this ransomware encrypts files but does not generate a decryption key.
It's not clear yet whether the decision to encrypt people's data permanently has been made intentionally or accidentally. However, it's clear that you will not be able to decrypt files encrypted by Thanatos ransomware even though you pay the ransom.
Thus, you should focus on Thanatos removal instead of risking to increase your damage. Unfortunately, deletion of the virus won't restore your files, but you will be able to use your PC safely again. If you have backups, simply plug in an external storage device after virus removal and recover files easily.
Those who do not have backups should use alternative data recovery methods that are provided at the end of this post. However, we cannot guarantee that they work. Cybersecurity researchers claim that the most effective, though time-consuming, the method to unlock files compromised by ransomware is to use brute force algorithm. For this purpose, you should contact professional IT experts.
To remove Thanatos from the computer safely, you have to obtain a reputable malware removal tool, such as or . If you cannot install security software, please follow the guide given below. Keep in mind that manual removal is not recommended due to the complexity of ransomware.
Thanatos belongs to the most difficult types of cyber threats. Hence, after the attack, it may have installed numerous harmful files, injected malicious code into legit system processes, and caused other changes to the system that cannot be safely fixed manually.
From our report of Jun 2018 · not reviewed since
Authors of file-encrypting viruses use multiple distribution methods to infect computers
Typically, ransomware viruses spread via malicious spam emails.
Thus, malware can sneak into the system when a user is tricked into opening Word, PDF or ZIP file that includes a malicious payload. However, security specialists from DieViren.de also report about other threats.
Ransomware can also be distributed as:
Therefore, you should be careful with content you click or download online. Additionally, to avoid ransomware helps installation of recent updates and robust security software.
- fake software update which appears as a pop-up when browsing the web;
- illegal or obfuscated program in file-sharing sites or networks;
- malicious ads.
From our report of Jun 2018 · not reviewed since
Termination of the Thanatos ransomware virus
We have mentioned at the beginning that you should not try to remove Thanatos manually.
We want to stress out that only experienced IT specialists can clean your PC without damaging it. Therefore, instead of locating files or registry entries created by ransomware, you should opt out for the automatic elimination method.
Automatic Thanatos removal can be performed with any professional malware removal program. However, we highly recommend using or . If crypto-virus is resistant and prevents from accessing security software, follow the steps below.
[GI=method-1]First of all, you should disable the virus to remove it automatically without any obstacles.
[GI=method-2]If the previous method did not help to remove Thanatos ransomware, follow these steps:
Nevertheless, it's not an official decryptor; it might still help to restore some of the files.
Take advantage of Windows Previous Versions feature
If System Restore was enabled before Thanatos ransomware attack, you can follow the steps below and get back access to the most important files:
If the ransomware did not delete Shadow Volume Copies, you could use ShadowExplorer to restore encrypted files.
Use a free Thanatos decryptor tool
Security experts from Cisco created a free ThanatosDecryptor.
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 Thanatos 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 .thanatos 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 Thanatos ransomware
How do I open .thanatos files?
You cannot open them by renaming or with another program, because the content of files ending in .thanatos has been encrypted. The only ways back are a working decryptor for the family, or clean copies from elsewhere:
- OneDrive versions
- File History
- an offline backup drive
- Previous Versions if the ransomware did not delete them
Identify the family first by uploading the ransom note and one encrypted file to ID Ransomware or No More Ransom. Avoid websites and programs that promise to open any encrypted file; they do not work and some are scams.
Is there a free Thanatos decryptor?
We last checked on 7 October 2026, and for Thanatos 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 "Thanatos 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.
Did Thanatos steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by Thanatos, but the only confirmed sign is files that end in .thanatos 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.
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.
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 Thanatos get on my computer?
The way Thanatos 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 .thanatos 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 Thanatos 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.
What does README.txt tell me about the ransomware?
Quite a lot. The file name README.txt, the wording, the contact addresses and the format of the personal ID are typical for each family. Uploading the note together with one encrypted file to ID Ransomware or No More Ransom's Crypto Sheriff usually names the family within seconds.
That name decides your options: some families have free decryptors, some can be partially recovered, and some cannot be decrypted at all. The note's claims about stolen data should be taken seriously but not at face value.
Should I reinstall Windows after the .thanatos attack?
Reinstalling removes the ransomware but not the encryption: your files ending in .thanatos stay encrypted afterwards. So first copy the encrypted files and the ransom note to a separate drive, in case a decryptor appears later. Then decide:
- a clean-up with an offline scan is often enough for home PCs
- while a full reset is safer if remote access was involved
- scans keep finding new items
Restore your backups only after the PC is clean, and change passwords from another device.
Will Fortect remove Thanatos?
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 Thanatos, 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
- Wikipedia: Advanced Encryption Standard (read October 7, 2026)
- Talos: Files Cannot Be Decrypted? Challenge Accepted. Talos Releases ThanatosDecryptor (read October 7, 2026)
- DieViren: DieViren (read October 7, 2026)
- Ars Technica: Here's why the epidemic of malicious ads grew so much worse last year (read October 7, 2026)
- CISA: StopRansomware (read October 7, 2026)