Kupidon ransomware: what it is and how to remove it

Kupidon ransomware - malware that encrypts data and demand payment from the victim by claiming to have a decryption tool needed for the proper file restoring.

The initial report about this new threat states that it is a possible copy of some other older ransomware because the ransom note text delivered via !KUPIDON_DECRYPT.TXT file resembles a threat from before, but that is not new since many actors reuse information or code from other threats to build their own malware.

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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Screenshot of Kupidon ransomware: virus
Kupidon ransomware as our 2020 report showed it.

Kupidon ransomware: summary

DistributionThe threat is delivered with the help of malicious files that can be placed on emails as attachments or downloaded from malware-laced pages, torrent services. The infiltration happens quickly, and users cannot notice the payload drop
NameKupidon ransomware
File marker.kupidon – file marker that is placed at the end after all the original names and file-type extensions once the encryption process is completed
DangerCryptocurrency-extortion based threats are dangerous because attacks involve money demands, blackmailing messages, and money. People can pay for nothing and end up losing money and data after all
Ransom amountAttackers ask for $300 from victims whose samples got analyzed. The amount is preferred to be obtained in the form of Bitcoin and can be determined for each victim separately judging on the value and amount of data encoded during the attack
Ransom noteKUPIDON_DECRYPT.TXT; the text is quoted in full below
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
Detection namesNo Microsoft detection name is known
Contactkupidon@cock.li
Encrypted file extension.kupidono
DecryptorNo free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates
DamageNot recorded in the old report
TypeFile-encrypting ransomware
SymptomsFiles renamed with a new extension and a ransom note left in folders
Evidence4 write-ups by security sites; no sample analysed yet
Encrypted files.kupidono
Attacker contactskupidon@cock.li
Free decryptorNo free decryptor is known (checked 7 October 2026)
First seen14 May 2020
Facts checked7 October 2026
  • File extension: .kupidono
  • Note file: KUPIDON_DECRYPT.TXT
  • Contact: kupidon@cock.li

From our report of May 2020 · not reviewed since

More from our earlier report on Kupidon ransomware

  • !KUPIDON_DECRYPT.TXT is the file that contains the message from virus creators and includes contact information, details on ransom amount and the unique victims' ID
  • Kupidon ransomware removal should be performed using anti-malware tools, so any associated programs can get deleted
  • As for the virus damage that ransomware possibly triggers in the background to affect the persistence of the virus, you should rely on or similar tools that can check for affected data or settings
  • 1) Send a few encrypted files (no more 3 files, no more 10 MB per letter) to kupidon@cock.li .
  • Dont forget to include you ID from !
  • 2) We will decipher them and send you back with bitcoin address for payment.
  • 3) After payment ransom for Bitcoin, we will send you a decryption program and aes-key with instructions.
  • If we can decrypt any of your files, we have no reason to deceive you after payment.

How Kupidon ransomware behaves

From our report of May 2020 · not reviewed since

Malware targets users data by dropping the payload via a malicious file

Payload droppers for the ransomware-type malware can be anything from trojans, other cyber threats, to files attached to email notifications that contain malicious macro triggering functionalities.

Malware script initiates the installation of the main launched of the threat, so the infection happens and the system gets affected significantly.

These files that spread malware can be disguised as PDFs, Microsoft Word, or Excel documents and state about important information, so people fall for the trick and download the attachment from a questionable email. At this point, users' interaction is needed because malicious macros need to be enabled. The file that you open shows a form to agree on, so the content can be displayed.

One-click and malware script gets dropped directly on the system. If you want to avoid such infiltration, you need to delete any suspicious emails after receiving them and rely on proper security tools before downloading anything from the internet, Most of such tools can check the attachment and show if that is safe to download.

From our report of May 2020 · not reviewed since

Kupidon ransomware termination includes cleaning infectious files from the system

When you encounter the Kupidon ransomware virus, you should take the additional infections and programs that can be loaded behind your back, into consideration.

Anything related to the malware that is left on the machine can affect the persistence of the ransomware and interfere with security tools, other methods of data recovery, and malware elimination.

Kupidon ransomware removal can be achieved with anti-malware tools that check the system for malware and intruders, deletes those payload files and other threats. Security programs like or can for such purposem but you may want to reboot the machine in Safe Mode with Networking first to get better results.

When you remove Kupidon ransomware using the anti-malware program, you can be sure that no additional threats can run in the background.

[GI=method-1]Rebooting the machine in Safe Mode with Networking can significantly lessen the frustration when terminating Kupidon ransomware with AV tools

[GI=method-2]System Restore is the feature that can help with malware elimination since it recovers computer in the previous state

Your device may get affected by Kupidon ransomware or you remove files unwantedly. Both times your data gets damaged.

Windows Previous Versions relies on recovering affected data

When you use System Restore gets enabled, Windows Previous Versions can also get used for file restoring

ShadowExplorer is the method that allows recovering the encrypted files

If Shadow Volume Copies don't cent affected, you can rely on ShadowExplorer

Kupidon ransomware decryption tool is not available

From our report of May 2020 · not reviewed since

Kupidon ransomware is the cryptovirus that targets companies and mainly spreads in Romania

Kupidon ransomware - malware that encrypts data and demand payment from the victim by claiming to have a decryption tool needed for the proper file restoring.

The initial report about this new threat states that it is a possible copy of some other older ransomware because the ransom note text delivered via !KUPIDON_DECRYPT.TXT file resembles a threat from before, but that is not new since many actors reuse information or code from other threats to build their own malware.

Also, the post from researchers reveals that targets of this cryptovirus are mainly companies, and most of them are related to Romania. There are not many samples, at the time, but more details reveal that threat is dangerous and can evolve petty quickly.

Kupidon ransomware virus is not reported to come from another family or malware developers. Once the machine is infected, that runs the encryption on common files using AES and RSA algorithms. File locking is ensuring that creators have a reason for the money demands and scary messages that come right after the encryption.

When images, documents, archives, or different types of files get encoded they become useless and receives .kupidon marker at the end, so the victim can differentiate which files got encrypted. Even though ransomware directly corrupts common files on the machine, system data can get affected when the malicious processes running in the background or parts of the system like registry entries and security tools altered.

Kupidon ransomware starts with the encryption process, during which files get appended with .kupidono extensions and ransom note indicating the same name of the ransomware get placed in various folders. This !KUPIDON_DECRYPT.TXT file is created to inform people about further actions and encourage them to pay the demanded amount for the criminals.

Unfortunately, the Kupidon ransomware virus is focused on getting money and making a profit. Your files, devices, and other belongings are not important for the cybercriminals, so trusting them is not a good option. Malicious actors may even offer the test decryption for you to fake that this is a legitimate service and that decryption tool works.

The test decryption prior to the payment can be performed on files no larger than 10 MB. This may be the case because criminals store some of these files for the purpose of tricking you that data got recovered. Do not fall for any of these tricks that attackers use.

The text displayed in Kupidon ransomware ransom note:

Kupidon ransomware mainly targets companies and businesses, so the ransom amount can go up a notch and be specific for the particular target. However, even large businesses shouldn't pay this demand and remove malware instead. The ransom payment page shows the following:

You need to remove Kupidon ransomware instead of paying the ransom because the options of getting your files may be false and not possible at all. Decryption tool officially is not released yet, so the option for file recovery is only one- data backups.

Of course, you can rely on some third-party programs and our suggestions below, but the best thing you can do when encountered such intruder is run the cleaning process.

Kupidon ransomware removal results are the best when you rely on professional anti-malware tools and can clean the threat completely alongside other possible infections or malicious files, applications. Security tools cannot recover those encrypted documents or images, but you shouldn't even consider file recovery until the system is virus-free.

Kupidon ransomware can easily run the encryption algorithms again and affect files you newly added on the machine. This way you lose all of your data. This can happen to your external data backup when you plug in the USB device to the still infected computer. We strongly advise staying away from criminals and terminating the threat ASAP.

The process of cleaning the machine can get difficult when Kupidon ransomware damages shadow volume copies, alters Windows registry entries, changes settings, or disable programs that can be helpful for either malware termination or file recovery. We have listed a few tips to bypass these changes below.

As for the virus damage that Kupidon ransomware causes, rely on optimization software or tools designed to repair computers like and run the full check for affected files. Later on, you can repair any corrupted parts of the system. Experts always note how important it is to get rid of the damage and repair functions as to the normal stage.

Screenshot of Kupidon ransomware: virus
Kupidon ransomware in our 2020 report.
Screenshot of Kupidon ransomware: screenshot
Kupidon ransomware in our 2020 report.

The Kupidon ransomware note

Text of KUPIDON_DECRYPT.TXT

All your files have been encrypted with Kupidon Virus.

Your unique id:

As a private person you can buy decryption for 300 $ in Bitcoins.

But before you pay, you can make sure that we can really decrypt any of your files.

The encryption key and ID are unique to your computer, so you are guaranteed to be able to return your files.

To do this:

1) Download and install Tor Browser (https://www.torproject.org/download/)

2) Open the http://oc3g3q5tznpubyasjgliqyykhxdfaqge4vciegjaapjchwtgz4apt6qd.onion/ web page in the Tor Browser and follow the instructions.

How to remove Kupidon 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 Kupidon 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.

  1. 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 Kupidon 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 quick settings with Wi-Fi turned off
    Windows 11: turn off Wi-Fi to take the PC offline.

    Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files

  2. Step 2: Save the ransom note and confirm the family

    Your files now end in .kupidono and the instructions are in KUPIDON_DECRYPT.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.

    A ransom note text file next to encrypted files in File Explorer
    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

  3. Step 3: Check for a free decryptor

    Our last check found that for Kupidon 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

  4. Step 4: Remove the ransomware before you restore or decrypt

    Removing Kupidon 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 Security Scan options with Microsoft Defender Antivirus offline scan selected
    Windows 11: Windows Security > Virus & threat protection > Scan options.

    Full procedure with screenshots: Run a Microsoft Defender Offline scan

  5. 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 shadows in 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.

    Command Prompt running vssadmin list shadows
    Windows 11: vssadmin list shadows shows whether shadow copies exist.

    Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files

  6. 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 Kupidon ransomware deleted may still be on the disk until something overwrites them. Install nothing new on the drive you want to recover from on the Windows 11 or Windows 10 PC.

    Full procedure with screenshots: Recover deleted files (Recycle Bin, backups, OneDrive) On uGetFix

Instructions for each browser and system

The detailed steps for every browser and system this guide covers. Open the one you use.

Manual removal using Safe Mode

Important! →
Manual removal guide might be too complicated for regular computer users. It requires advanced IT knowledge to be performed correctly (if vital system files are removed or damaged, it might result in full Windows compromise), and it also might take hours to complete. Therefore, we highly advise using the automatic method provided above instead.

Step 1. Access Safe Mode with Networking

Manual malware removal should be best performed in the Safe Mode environment.

Windows 7 / Vista / XP

  1. Click Start > Shutdown > Restart > OK.
  2. 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.
  3. Select Safe Mode with Networking from the list.Windows 7/XP

Windows 10 / Windows 8

  1. Right-click on Start button and select Settings.
    Settings
  2. Scroll down to pick Update & Security.
    Update and security
  3. On the left side of the window, pick Recovery.
  4. Now scroll down to find Advanced Startup section.
  5. Click Restart now.
    Reboot
  6. Select Troubleshoot.Choose an option
  7. Go to Advanced options.Advanced options
  8. Select Startup Settings.Startup settings
  9. Press Restart.
  10. Now press 5 or click 5) Enable Safe Mode with Networking.Enable safe mode

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:

  1. Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
  2. Click on More details.
    Open task manager
  3. Scroll down to Background processes section, and look for anything suspicious.
  4. Right-click and select Open file location.
    Open file location
  5. Go back to the process, right-click and pick End Task.
    End task
  6. Delete the contents of the malicious folder.

Step 3. Check program Startup

  1. Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
  2. Go to Startup tab.
  3. Right-click on the suspicious program and pick Disable.
    Startup

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:

  1. Type in Disk Cleanup in Windows search and press Enter.
    Disk cleanup
  2. 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).
  3. Scroll through the Files to delete list and select the following: Temporary Internet Files
    Downloads
    Recycle Bin
    Temporary files
  4. Pick Clean up system files.
    Delete temp files
  5. 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.

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

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 Kupidon 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 .kupidono 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 Kupidon ransomware

How do I open .kupidono files?

You cannot open them by renaming or by choosing another program. The .kupidono ending shows that Kupidon 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 Kupidon ransomware. Store the encrypted files on an external disk until then.

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.

Is there a free Kupidon ransomware decryptor?

We last checked on 7 October 2026, and for Kupidon 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 "Kupidon 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.

How did Kupidon ransomware get on my computer?

The way Kupidon 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 .kupidono 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 Kupidon ransomware steal my files or passwords?

We do not know yet. Nothing published so far shows data theft by Kupidon ransomware, but the only confirmed sign is files that end in .kupidono 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 Kupidon 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 .kupidono from the file names?

You can try it on a copy, but for real ransomware it will not help. The .kupidono 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 KUPIDON_DECRYPT.TXT tell me about the ransomware?

Quite a lot. The file name KUPIDON_DECRYPT.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.

Will Fortect remove Kupidon 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 Kupidon 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

  1. Twitter: There's a ransomware (read October 7, 2026)
  2. Comparitech: What is RSA encryption and how does it work? (read October 7, 2026)
  3. CISA: StopRansomware (read October 7, 2026)
  4. No More Ransom (read October 7, 2026)
  5. FTC: How to recognize, remove and avoid malware (read October 7, 2026)

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