Poison ransomware: what it is and how to remove it
Locking personal files on the computer is bad enough, but asking for money to unlock them became a familiar phenomenon all over the world. Poison ransomware is another addition to an ever-expanding list of new cryptomalware strains which first showed up in the middle of October of 2021.
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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Poison ransomware: summary
| Name | Poison ransomware |
|---|---|
| Type | Ransomware, file-locking malware, cryptovirus |
| File extension | .poison is appended at the end of each file name |
| Ransom note | ___RECOVER__FILES__.poison.txt and a pop-up window titled "!Ups"; the text is quoted in full below |
| Contact | bankinter.promo@protonmail.com |
| Ransom size | 0.01 BTC, to be transferred to [payment address omitted] Bitcoin wallet |
| 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
| File Recovery | If no backups are available, recovering data is almost impossible. Nonetheless, we suggest you try the alternative methods that could help you in some cases – we list them below |
|---|---|
| Detection names | No Microsoft detection name is known |
| Encrypted file extension | .poison |
| 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 Windows Security "Threats found" notification and a ransom note left in folders |
| Evidence | 4 write-ups by security sites; no sample analysed yet |
| Encrypted files | .poison |
| Free decryptor | No free decryptor is known (checked 7 October 2026) |
| First seen | 14 October 2021 |
| Microsoft Defender name | Ransom:MSIL/Cryptolocker.PDH!MTB |
| Facts checked | 7 October 2026 |
Which name will your scanner show?
Microsoft's name for Poison ransomware is Ransom:MSIL/Cryptolocker.PDH!MTB.
Defender sorts threats by category first, so the word before the colon tells you what kind of program was found, even if the family name means nothing to you.
Do not search for a removal tool by the detection name alone; fake "removal tools" use the same keywords. How the naming works is explained in our guide to antivirus detection names.
- File extension:
.poison - Note file:
the ransom note
From our report of Oct 2021 · not reviewed since
Poison ransomware is a type of malware designed to extort money from you
Locking personal files on the computer is bad enough, but asking for money to unlock them became a familiar phenomenon all over the world.
Poison ransomware is another addition to an ever-expanding list of new cryptomalware strains which first showed up in the middle of October of 2021.
After the virus manages to break into a Windows machine, it immediately begins its malicious activities, infecting the whole system or even network, if the PC is connected to one, immediately.
These modifications are required in order for malware to fulfill its main goal - to lock all pictures, documents, videos, and other types of files. This process can be a bit longer than the infection one, as it highly depends on the size of the files susceptible to encryption.
At this time, malware renders all files useless, stripping them off their original icons and locking them with a secure algorithm. While data can no longer be accessed or modified, it does not mean that it is corrupted. Poison ransomware creates a complex, unique key that is sent to the attackers' servers immediately. This key is then used to blackmail users into paying money for file retrieval.
To make victims aware of what just happened, malware authors leave a ransom note ___RECOVER__FILES__.poison.txt, which is placed on the desktop and any other folders where locked files are located. The ransom note is brief but informative; it claims that users need to process payment of 0.01 BTC into the [payment address omitted] Bitcoin wallet and then an email with the transaction ID sent to ankinter.promo@protonmail.com.
Poison virus is a new ransomware strain, and no connections have been found with other ransomware families. Nonetheless, man new and experimental ransomware shows up after some members leave a larger cybercriminals group to increase profits from the illegal activities. Likewise, new people within the cybercriminal world can also be starting their own businesses.
In the case of the latter, there are no established principles that the group works by, hence there could be bugs within the ransomware encryption codes or the returned decrytpion tools might fail to work. This is why it is not advised by experts to trust hackers behind ransomware and send them the money they require. The full ransom note reads:
Looking at it, it seems like crooks are trying to be approachable and "nice" within the last sentence. This is one of the tactics employed by ransomware authors; as we observed in other malware strains, ransom notes are threatening and even put up a timer before the decryption key is allegedly deleted from the crooks' server.
In any case, it is up to you whether you want to risk your money and pay the required Bitcoin, although be warned - you might lose your files and money. While it is true that there is no working decryption tool that would guarantee a file recovery, you could try several alternative methods we list below. But before that, you need to remove Poison ransomware from your device.
From our report of Oct 2021 · not reviewed since
More from our earlier report on Poison ransomware
- 0.01 BTC, to be transferred to 1EHXj2AvyeCAKTzBdqbDmmceswJEciE7kj Bitcoin wallet
- Manual virus removal is not recommended, as it might be difficult for regular users.
- Instead, or other anti-malware tools should be used
- Malware can seriously tamper with Windows systems, causing errors, crashes, lag, and other stability issues after it is terminated.
- Free Ransomware Decryptors by Kaspersky
The Poison ransomware note
!Your files have been encrypted.
To get back all them, send0.01 bitcoin(s) to BTC address: [payment address omitted]
So, email your transaction ID to: bankinter.promo@protonmail.com
Thanks for cooperate and good luck next time!
Encryption Log:
How to remove Poison 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 Poison 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 Poison 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
.poisonand the instructions are inthe ransom note. 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 Poison ransomware, 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 Poison 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 Poison 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.
Access Safe Mode to remove malware from Windows
If malware is not letting you use antivirus in normal mode, access Safe Mode and perform a full system scan from there. Safe Mode reduces the number of active processes, which may prevent some malware from interfering with security tools.
Windows 10 / Windows 11
- Right-click on Start button and select Settings.
- Select System (Windows 11) or Update & Security (Windows 10).
- 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.
- Click Restart.
- Press 5 or click 5) Enable Safe Mode with Networking.
Once you reach Safe Mode, launch , , or another reputable antivirus, update it with the latest definitions, and perform a full system scan to eradicate malware and all its malicious components.
Create data backups to avoid file loss in the future
Report the incident to your local authorities
Ransomware is a lucrative, highly illegal business, and authorities are actively targeting ransomware operators. The level of investigation and follow-up depends on the country, the scale of the incident, and whether the attack is linked to known ransomware groups. To increase the likelihood of identifying the culprits, the agencies need information. In many cases, reports are used primarily for intelligence gathering, trend analysis, and victim support rather than immediate identification of attackers.
Therefore, by reporting the crime, you could help stop the cybercriminal activities and catch the threat actors. Reporting does not guarantee investigation or recovery of data, but it contributes to broader efforts to track ransomware campaigns. Make sure you include all the possible details, including how did you notice the attack, when it happened, etc. Relevant details may also include affected systems, ransom demands, cryptocurrency wallet addresses, and any communication with the attackers. Additionally, providing documents such as ransom notes, encrypted files, or malware executables would be beneficial.
Law enforcement agencies typically deal with online fraud and cybercrime, although it depends on where you live. Here is the list of local authority groups that handle incidents like ransomware attacks, sorted by country:
- USA - Internet Crime Complaint Center IC3
- United Kingdom - ActionFraud
- Canada - Canadian Anti-Fraud Centre
- Australia - ScamWatch
- New Zealand - ConsumerProtection
- Germany - Polizei
- France - Ministère de l'Intérieur
If your country is not listed above, you should contact the local police department or communications center.
From our report of Oct 2021 · not reviewed since
Delete malware from your system
After the ransomware is done with encrypting all files, its main job is done.
Hence, some infections simply self-delete as soon as the data-locking process is complete, although this is not a rule, and some malware continues running in the background due to various reasons.
For example, it might continue locking all the incoming data (if such is placed on the infected PC), or stealing personal information in the background. Besides, malware is commonly spread in bulks, so there might be a dangerous virus installed as well.
Thus, it is vital to use security software to remove the Poison virus from your system, along with any other additional threats. Download , , or another reputable anti-malware and perform a full system scan to eliminate all the malicious components at once.
In fact, security software is your number one weapon against ransomware infections, as it can stop it before it manages to encrypt files. According to Virus Total, this virus can be detected under the following names:
Note: ransomware might tamper with security software and prevent it from working. If that happens, ever to the instructions at the bottom of this post to access Safe Mode and scan the system from there to bypass malware's malicious features.
- Gen:Heur.Ransom.REntS.Gen.1
- Trojan.Ransom.Filecoder
- A Variant Of MSIL/Filecoder.AEN
- Ransom:MSIL/Cryptolocker.PDH!MTB
- Msil.Trojan.Gen.Ejex
- Ransom.FileCryptor, etc.
From our report of Oct 2021 · not reviewed since
Attempt to recover .poison files with these methods
As previously mentioned, sending money to ransomware creators can be risky.
It also motivates them to infect more victims to acquire more money, hence the illegal business prospers. Instead of doing that, you should try using the following methods to recover the locked files. There are two things you should make sure of before proceeding:
During the recovery process listed below, encrypted files might get corrupted permanently, so it is vital to keep them on a separate medium. You can use a USB flash drive or similar external storage device; also, using remote cloud services can also be very convenient - we provide instructions on how to backup files on OneDrive and Google Drive below.
- You scanned your PC with security software and malware is no longer present on it
- You made backups of locked files.
From our report of Oct 2021 · not reviewed since
Use recovery software
- Download .
- Double-click the installer to launch it.
- Follow on-screen instructions to install the software.
- As soon as you press Finish, you can use the app.
- Select Everything or pick individual folders where you want the files to be recovered from.
- Press Next.
- At the bottom, enable Deep scan and pick which Disks you want to be scanned.
- Press Scan and wait till it is complete.
- You can now pick which folders/files to recover - don't forget you also have the option to search by the file name!
- Press Recover to retrieve your files.
From our report of Oct 2021 · not reviewed since
Wait for a decryptor
Most fully-working ransomware use encryption algorithms such as AES or RSA to lock up data securely.
This means that the decryption key can only be retrieved from cybercriminals' servers, although, obviously, they are not willing to give it up for free and ask for money in exchange for it.
Luckily, some ransomware is far from perfect and has bugs within their encryption process, which allows security experts to create a working decryption tool, providing it for victims for free.
Alternatively, law enforcement has previously seized the servers of malware authors, which allowed them to release keys to the public. Thus, use the following links to find a decryption tool, although you should keep in mind that it might take time before a working one is available, if at all.
- No More Ransom Project
- Free Ransomware Decryption Tools from Emsisoft
From our report of Oct 2021 · not reviewed since
Take care of your system health
Regardless of whether the above methods helped you to restore files or not, you should not neglect your Windows system.
After malware infection, it might start malfunctioning - crashing, lagging, fail to launch applications, returning errors, and much more. Thus, we strongly recommend you follow the below instructions to repair your system instead of reinstalling it altogether.
By employing this tool, you would not have to worry about future computer issues, as most of them could be fixed quickly by performing a full system scan at any time. Most importantly, you could avoid the tedious process of Windows reinstallation in case things go very wrong due to one reason or another.
- Download
- Click on the ReimageRepair.exe
- If User Account Control (UAC) shows up, select Yes
- Press Install and wait till the program finishes the installation process
- The analysis of your machine will begin immediately
- Once complete, check the results - they will be listed in the Summary
- You can now click on each of the issues and fix them manually
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
Poison ransomware could only hurt the files that had no second copy, and the signs (files that end in .poison and no longer open) 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.
Stream videos without limitations, no matter where you are
There are multiple parties that could find out almost anything about you by checking your online activity.
While this is highly unlikely, advertisers and tech companies are constantly tracking you online. The first step to privacy should be a secure browser that focuses on tracker reduction to a minimum.
Even if you employ a secure browser, you will not be able to access websites that are restricted due to local government laws or other reasons. In other words, you may not be able to stream Disney+ or US-based Netflix in some countries. To bypass these restrictions, you can employ a powerful VPN, which provides dedicated servers for torrenting and streaming, not slowing you down in the process.
Data backups are important - recover your lost files
Ransomware is one of the biggest threats to personal data.
Once it is executed on a machine, it launches a sophisticated encryption algorithm that locks all your files, although it does not destroy them. The most common misconception is that anti-malware software can return files to their previous states. This is not true, however, and data remains locked after the malicious payload is deleted.
While regular data backups are the only secure method to recover your files after a ransomware attack, tools such as can also be effective and restore at least some of your lost data.
Questions about Poison ransomware
How do I open .poison files?
You cannot open them by renaming or by choosing another program. The .poison ending shows that Poison 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 Poison ransomware. Store the encrypted files on an external disk until then.
Is there a free Poison ransomware decryptor?
We last checked on 7 October 2026, and for Poison 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 "Poison 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.
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 Poison ransomware get on my computer?
The way Poison 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 .poison 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 Poison ransomware steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by Poison ransomware, but the only confirmed sign is files that end in .poison 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 Poison 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 .poison from the file names?
You can try it on a copy, but for real ransomware it will not help. The .poison 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.
What does the name Ransom:MSIL/Cryptolocker.PDH!MTB tell me?
Microsoft builds names in a fixed order:
- category
- then platform
- then family
- sometimes followed by a variant letter
- a suffix
The category is the most useful part for you. Trojan, Backdoor and PWS mean real malware that can download more, give remote access or steal passwords. PUA means unwanted software.
Ransom means ransomware. Suffixes such as !ml or !MTB mean the detection came from machine learning or behaviour analysis. Search for the family part of Ransom:MSIL/Cryptolocker.PDH!MTB together with the word Microsoft to find its entry in Microsoft's security encyclopedia.
Will Fortect remove Poison 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 Poison 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
- Dieviren: Dieviren (read October 7, 2026)
- Virus Total: 15464657cfae95a326426093c9e12daab54bd9f61c3bc63a2cf5abe975a0e278 (read October 7, 2026)
- Wikipedia: Software bug (read October 7, 2026)
- CISA: StopRansomware (read October 7, 2026)
- No More Ransom (read October 7, 2026)