SUMMON ransomware: what it is and how to remove it
SUMMON ransomware is a file-locking virus that encrypts all personal victim data and generates ransom notes which demand to forward Bitcoins to the assailants for a decryption tool. Also, encrypted files are renamed in a complex manner.
Facts checked October 6, 2026. Removal steps tested on Windows 11 (26H2) and checked against Microsoft's and the browser makers' current documentation. Sections marked as our earlier report are the original text: they describe the threat as it was then and have not been reviewed since. The 2026 status, the removal steps and the questions are current.
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SUMMON ransomware: summary
| Distribution | Spam emails, file-sharing platforms, RDP attacks |
|---|---|
| name | SUMMON ransomware |
| type | Ransomware, cryptovirus, file-locker |
| Appended file extension | Renamed files look like this – [SummonunLock@gmail.com][id=XXXXXXXX]original_filename.SUMMON |
| Ransom note | #ReadThis.HTA, #ReadThis.TXT |
| Criminal contact details | summonunlock@gmail.com, summonunlock@mailfence.com. Two more possible addresses – Dude@mailfence.com, Summon@nuke.africa |
| 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 14 more facts
| Malware removal | Use dependable anti-malware software to remove SUMMON ransomware virus from all infected devices |
|---|---|
| Detection names | No Microsoft detection name is known |
| Encrypted file extension | .summon |
| Decryptor | No free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates |
| Damage | Not recorded in the old report |
| Name | SUMMON ransomware |
| Type | File-encrypting ransomware |
| Symptoms | Files renamed with a new extension and a ransom note left in folders |
| Evidence | 4 write-ups by security sites; no sample analysed yet |
| Encrypted files | .summon |
| Attacker contacts | summonunlock@gmail.com |
| Free decryptor | No free decryptor is known (checked 6 October 2026) |
| First seen | 2 February 2021 |
| Facts checked | 6 October 2026 |
- File extension:
.summon - Note file:
ReadThis.TXT - Contact:
summonunlock@gmail.com
From our report of Feb 2021 · not reviewed since
More from our earlier report on SUMMON ransomware
- Powerful tools like the app should be used to repair any and all system damage that was caused during the encryption
How SUMMON ransomware behaves
From our report of Feb 2021 · not reviewed since
SUMMON ransomware – a cryptovirus developed for Bitcoin extortion
SUMMON ransomware is a file-locking virus that encrypts all personal victim data and generates ransom notes which demand to forward Bitcoins to the assailants for a decryption tool.
Also, encrypted files are renamed in a complex manner. Original filenames are prepended with one of the attackers' email addresses summonunlock@gmail.com along with an appointed victim ID (both in brackets) and then appended with a .SUMMON extension.
If a victim had a file named a.pdf, it would now look like [SummonunLock@gmail.com][id=XXXXXXXX]a.pdf.SUMMON (Xs' stand for user ID). Two ransom notes appear when that's finished, one as a text file #ReadThis.TXT, and one as an HTML document, #ReadThis.HTA.
If you see any symptoms that your device might be infected with SUMMON ransomware virus, please don't panic and make rash decisions. It's not the end of the world. We have searched into the activity of the ransomware and other cybersecurity specialists' research shows that it is possible to remove the threat. This article contains a summary, distribution methods, data recovery options, and removal methods of this computer infection.
Ransomware has been lurking in the shadows of the internet for a long time now, and it won't stop spreading any time soon. There are ransomware families and rogue ransomware.
It can target regular people as well as big corporations. New versions are developed daily. Here are a few examples of the latest ones:
All of them might use different encryption techniques, distinct ransom notes, various appending methods, and extensions. Still, all of their goals are the same - frightening their victims into submitting to the assailants' demands. That's done by using various scare tactics in the ransom notes.
Here's what message developers of SUMMON ransomware send to their victims:
Usually, a few files' free decryption is guaranteed to prove that a necessary decryption tool exists (including SUMMON ransomware virus). Sometimes a video of the decryptor in action is added. Victims are urged not to use any third-party software to unlock the files, as the only way to do that rests in the cybercriminals' hands.
In many cases, that might be true, but agreeing with the assailants' demands is the worse thing any SUMMON ransomware victim can do. The send money motives the cybercriminals to expand their whole illegal operation and funds their research and development. The only way to stop ransomware from spreading is if victims stop paying the ransom.
Therefore, remove SUMMON ransomware from your devices. Please remember to keep the virus databases of either of these apps updated, and they might prevent such mishaps in the future.
Ransomware-type viruses tend to mess with system files and settings, that could lead to various abnormal system behavior. So to finish SUMMON ransomware removal, users will have to use another tool.
- 0l0lqq virus
- URSA virus
- Pola virus
- VashSorena virus.
From our report of Feb 2021 · not reviewed since
Watch out for unsolicited attachments, and hyperlinks in emails
threat actors behind ransomware have many spreading options, including Remote Desktop Protocol attacks, deceptive ads, file-sharing platforms, and so on.
Although, our research suggests that one of the most popular ransomware distribution options is spam emails.
Ransomware payload files can be hidden in either infected email attachments or hyperlinks. Cryptoviruses might be hidden as practically any file type, including .zip, .rar, .xlsm, .exe, .docx, .pdf, etc. As soon as either of the two options are clicked and opened, a virus might find its way onto the device and start encryption.
Users have to be aware that cybercriminals are always on the hunt. Emails that urge users to install software updates, or download a crucial document, are most likely phishing emails. Watch for grammatical mistakes, strange domains, and other irregularities to identify a spam email.
The SUMMON ransomware note
Your SERVER/COMPUTER is encrypted by us !_
Hello Admin/Guest!
=> All your data is encrypted by us ..
=> Your Server Unique ID : [-]
=> Do you want to decrypt your data?
=> To trust us, first send us a 100-200 KB file,
we will decrypt it to build trust for you.
=> What should you do after building trust?
Help
(
All your data is encrypted,
If your data is important and you want to decrypt it,
You must pay the bitcoin amount set by us,
Send a message to our emails first, after pricing, us and your trust,
Do a Google search to buy bitcoins,
For example: "Buy bitcoins in rubles".
After purchasing Bitcoin, you must
transfer the Bitcoin to our wallet,
After payment, the decryption tool will be sent to you
along with how to execute it properly
)
ENCRYPTER@server ~ $ To contact us, first send a message to our first email.
SummonunLock@gmail.com
ENCRYPTER@server # If your email is not answered after 24 hours, our email may be blocked.
So send a message to our second email.
SummonunLock@mailfence.com
King Of Ransom
SUMMON Ran$omW4rE
How to remove SUMMON 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 SUMMON 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
SUMMON ransomware encrypts everything it can reach, including drives and shares you connect later. Cut the network first: cable out, or Wi-Fi off from the taskbar.
Then unplug every USB stick and backup disk and pause cloud sync, so the encrypted versions do not replace your online copies. Do not reconnect any of them until the ransomware is removed from the Windows 11 or Windows 10 PC.
Windows 11: turn off Wi-Fi to take the PC offline. Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 2: Save the ransom note and confirm the family
Copy
ReadThis.TXTand one or two files ending in.summonto a USB stick, and leave the originals where they are.From another device, upload the note and a sample file to ID Ransomware or No More Ransom's Crypto Sheriff, which name the family from the note, the extension and the file structure.
Write down the contact address and your personal ID from the note, because a decryptor or the police may ask for them.
Warning: Never contact the attackers from the infected Windows 11 or Windows 10 PC.
Windows 11: the ransom note and encrypted files to copy for identification. Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 3: Check for a free decryptor
For SUMMON ransomware, no free decryptor is known (checked 6 October 2026). Search the family name in the No More Ransom decryption tools list and in the free decryptors of Emsisoft, Avast and Kaspersky, because new tools appear years after an attack.
Important: Keep the encrypted files even if nothing works today, and do not pay before every free option is ruled out: payment does not guarantee a working key.
Decryptors run on Windows 11 and Windows 10, but only after the ransomware itself is removed.
Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 4: Remove the ransomware before you restore or decrypt
Restoring or decrypting files while SUMMON ransomware still runs lets it encrypt them again. Run a Full scan in Windows Security > Virus & threat protection > Scan options, then the Microsoft Defender Antivirus (offline scan).
If the ransomware blocks Windows Security, start Safe Mode with Networking and scan from there. Some families install a password stealer as well, so let both scans finish on Windows 11 or Windows 10.
Windows 11: Windows Security > Virus & threat protection > Scan options. Full procedure with screenshots: Run a Microsoft Defender Offline scan
Step 5: Look for shadow copies of the files
Open Command Prompt as administrator and run
vssadmin list shadows. If it lists copies dated before the attack, right-click a folder with encrypted files in File Explorer, choose Properties > Previous Versions, and open or restore a version from before that date.ShadowExplorer, a free tool, shows the same copies when the tab is empty or hidden. Most current families delete shadow copies, so an empty list is normal, but the check takes two minutes on Windows 11 or Windows 10.
Windows 11: vssadmin list shadows shows whether shadow copies exist. Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files
Step 6: Restore the files from a backup or recover deleted originals
Restore from an external backup, File History or OneDrive's version history, choosing a date before the attack. Connect the backup drive only after the scans are clean, or the ransomware encrypts it too.
If there is no backup, file recovery software can sometimes find the deleted originals, because some ransomware writes an encrypted copy and deletes the original file.
Stop writing to the drive and try recovery on Windows 11 or Windows 10 before new files overwrite the space.
Full procedure with screenshots: Recover deleted files (Recycle Bin, backups, OneDrive) On uGetFix
Instructions for each browser and system
The detailed steps for every browser and system this guide covers. Open the one you use.
Manual removal using Safe Mode
Important! →
Manual removal guide might be too complicated for regular computer users. It requires advanced IT knowledge to be performed correctly (if vital system files are removed or damaged, it might result in full Windows compromise), and it also might take hours to complete. Therefore, we highly advise using the automatic method provided above instead.
Step 1. Access Safe Mode with Networking
Manual malware removal should be best performed in the Safe Mode environment.
Windows 7 / Vista / XP
- Click Start > Shutdown > Restart > OK.
- When your computer becomes active, start pressing F8 button (if that does not work, try F2, F12, Del, etc. - it all depends on your motherboard model) multiple times until you see the Advanced Boot Options window.
- Select Safe Mode with Networking from the list.
Windows 10 / Windows 8
- Right-click on Start button and select Settings.
- Scroll down to pick Update & Security.
- On the left side of the window, pick Recovery.
- Now scroll down to find Advanced Startup section.
- Click Restart now.
- Select Troubleshoot.
- Go to Advanced options.
- Select Startup Settings.
- Press Restart.
- Now press 5 or click 5) Enable Safe Mode with Networking.
Step 2. Shut down suspicious processes
Windows Task Manager is a useful tool that shows all the processes running in the background. If malware is running a process, you need to shut it down:
- Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
- Click on More details.
- Scroll down to Background processes section, and look for anything suspicious.
- Right-click and select Open file location.
- Go back to the process, right-click and pick End Task.
- Delete the contents of the malicious folder.
Step 3. Check program Startup
- Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
- Go to Startup tab.
- Right-click on the suspicious program and pick Disable.
Step 4. Delete virus files
Malware-related files can be found in various places within your computer. Here are instructions that could help you find them:
- Type in Disk Cleanup in Windows search and press Enter.
- Select the drive you want to clean (C: is your main drive by default and is likely to be the one that has malicious files in).
- Scroll through the Files to delete list and select the following:
Temporary Internet Files
Downloads
Recycle Bin
Temporary files - Pick Clean up system files.
- You can also look for other malicious files hidden in the following folders (type these entries in Windows Search and press Enter):
%AppData%
%LocalAppData%
%ProgramData%
%WinDir%
After you are finished, reboot the PC in normal mode.
From our report of Feb 2021 · not reviewed since
Instructions for SUMMON file virus removal from Windows computers
If you got your device infected with SUMMON ransomware virus, it's your anti-malware software fault, not yours.
The main thing is not to panic. Don't even look at the ransom note. Download and install professional anti-malware tools such as and that will help you eliminate this threat.
It's worth mentioning that SUMMON ransomware removal won't decrypt your files. There could be third-party tools that you could try (displayed at the bottom of this page). If none of them work, extract all essential files to an external storage device and wait for a public decryption key or tool to be made available.
Use the aforementioned tools to remove SUMMON ransomware from the infected device automatically. Once that's done, run a full system scan with the app to fix any system irregularities, such as corrupted registry and other core settings/files. If left unattended, these changes might result in crashes, freezes, BSoD, and other system issues.
[GI=method-1]If virus prevents from opening anti-malware solutions, you can do that in Safe Mode with Networking
[GI=method-2]Removing file-locking parasites with System Restore
This app might help restore .SUMMON extension files.
Restoring files with Windows Previous Version
This powerful feature might allow victims to recover .SUMMON extension files one at a time.
Using Shadow Explorer to retrieve old files
Decryption for SUMMON ransomware is not created
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 SUMMON 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 .summon and no longer open.
Setting it up step by step: 3-2-1 backups on Windows 11 and 10.
Access your website securely from any location
When you work on the domain, site, blog, or different project that requires constant management, content creation, or coding, you may need to connect to the server and content management service more often. The best solution for creating a tighter network could be a dedicated/fixed IP address.
If you make your IP address static and set to your device, you can connect to the CMS from any location and do not create any additional issues for the server or network manager that needs to monitor connections and activities. VPN software providers like can help you with such settings and offer the option to control the online reputation and manage projects easily from any part of the world.
Recover files after data-affecting malware attacks
While much of the data can be accidentally deleted due to various reasons, malware is one of the main culprits that can cause loss of pictures, documents, videos, and other important files.
More serious malware infections lead to significant data loss when your documents, system files, and images get encrypted. In particular, ransomware is is a type of malware that focuses on such functions, so your files become useless without an ability to access them.
Even though there is little to no possibility to recover after file-locking threats, some applications have features for data recovery in the system. In some cases, can also help to recover at least some portion of your data after data-locking virus infection or general cyber infection.
Questions about SUMMON ransomware
How do I open .summon files?
You cannot open them by renaming or with another program, because the content of files ending in .summon 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.
Should I pay the ransom in ReadThis.TXT?
Not before you have tried everything else. Identify the family from ReadThis.TXT and one encrypted file, check No More Ransom for a free decryptor, and look for clean copies in OneDrive, backups and Previous Versions.
Paying funds further attacks, may be illegal if the group is sanctioned, and is no promise of a working key: many victims get partial or broken decryption. If you consider paying for business-critical data, involve the police and a professional incident responder first, and never pay through intermediaries who promise their own decryption.
Did SUMMON ransomware steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by SUMMON ransomware, but the only confirmed sign is files that end in .summon 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 there a free SUMMON ransomware decryptor?
We last checked on 6 October 2026, and for SUMMON 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 "SUMMON 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.
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 SUMMON ransomware get on my computer?
The way SUMMON 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 .summon 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 SUMMON ransomware the same as other ransomware with a similar name?
Not necessarily. Ransomware names come from the file extension, the note or a word in the code, so unrelated families often end up with similar names, and one family can appear under several names. The difference matters: a decryptor or advice for one family does not fit another and can damage files.
Compare the ending added to your files and the exact name of the note with the summary table at the top of this guide, then upload the note and one encrypted file to ID Ransomware from a clean device. If the result names another family, follow the guide for that family instead.
Can I delete ReadThis.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. ReadThis.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.
My files got .summon overnight. What happened?
Ransomware often runs at night or when the PC is idle, so the encryption finishes before anyone notices. It usually entered earlier through a cracked program, a fake installer, an e-mail attachment or remote desktop with a weak password.
The .summon extension marks every file it reached. Start by disconnecting the PC from the network, then identify the family from the ransom note and one encrypted file, check for a decryptor, and look for copies in backups and OneDrive before you consider anything else.
Will Fortect remove SUMMON 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 SUMMON 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
- Medium: Ransomware encryption techniques (read October 6, 2026)
- Virusai: Virusai (read October 6, 2026)
- CISA: StopRansomware (read October 6, 2026)
- No More Ransom (read October 6, 2026)
- FTC: How to recognize, remove and avoid malware (read October 6, 2026)