Arena ransomware: what it is and how to remove it
Arena ransomware is a file-encrypting virus that is associated with the Dharma ransomware family. Ransomware usually gets inside the system via malicious email and starts data encryption.
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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Arena ransomware: summary
| Name | Arena ransomware |
|---|---|
| Type | File-locking virus, crypto-malware |
| File extension | .arena appended to each of the personal files |
| Ransom note | FILES ENCRYPTED.txt and a pop-up window titled Macgregor@aolonline.top |
| Detection | TR/Dropper.Gen, Trojan.Ransom.Crysis.E, Ransom-Dharma!F315C5467A60, Ransom.Win32.CRYSIS.SM, W32.Ransom.Gen, etc. More on Virus Total; no Microsoft detection name is known for this name |
| Malware removal | Use reputable anti-malware software to eliminate the virus |
| 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 12 more facts
| Contact | sindragosa@bigmir.net, chivas@aolonline.top, macgregor@aolonline.top |
|---|---|
| Encrypted file extension | .arena |
| 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 and a ransom note left in folders |
| Evidence | 6 write-ups by security sites; no sample analysed yet |
| Encrypted files | .arena |
| Attacker contacts | sindragosa@bigmir.net |
| Free decryptor | No free decryptor is known (checked 6 October 2026) |
| First seen | 11 June 2021 |
| Facts checked | 6 October 2026 |
What to search your PC and browser for
- File extension:
.arena - Note file:
_HELP_INSTRUCTION.TXT - Contact:
sindragosa@bigmir.net
The Arena ransomware note
all your data has been locked us
You want to return?
write email sindragosa@bigmir.net
How to remove Arena 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 Arena 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
Arena 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
_HELP_INSTRUCTION.TXTand one or two files ending in.arenato 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 Arena 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 Arena 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.
Repair damaged system components
Once a computer is infected with malware, its system is changed to operate differently. For example, an infection can alter the Windows registry database, damage vital bootup and other sections, delete or corrupt DLL files, etc. Once a system file is damaged by malware, antivirus software is not capable of doing anything about it, leaving it just the way it is. Consequently, users might experience performance, stability, and usability issues, to the point where a full Windows reinstall is required.
Therefore, we highly recommend using a one-of-a-kind, patented technology of repair. Not only can it fix virus damage after the infection, but it is also capable of removing malware that has already broken into the system thanks to several engines used by the program. Besides, the application is also capable of fixing various Windows-related issues that are not caused by malware infections, for example, Blue Screen errors, freezes, registry errors, damaged DLLs, etc.
- Download the application by clicking on the link above
- 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
- If you see many problems that you find difficult to fix, we recommend you purchase the license and fix them automatically.
By employing , 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.
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.
Important steps to take before you begin malware removal
File encryption is one component of a ransomware infection, which may also include credential theft, persistence mechanisms, and lateral movement. However, it is important to understand that malware may perform various changes within a Windows operating system, including persistence, scheduled tasks, registry modifications, and security feature tampering.
IMPORTANT for those without backups! →
If you attempt to use security or recovery software immediately, you might permanently damage your files, and even a working decryptor then would not be able to save them.
Before you proceed with the removal instructions below, you should copy the encrypted files onto a separate medium, such as USB flash drive or SSD, and then disconnect them from your computer. The storage device should remain disconnected after copying to prevent accidental modification or deletion. Encrypted data itself does not contain active malicious code, but only the encrypted files—not executables or scripts—should be transferred.
The instructions below might initially seem overwhelming and complicated, but they are not difficult to understand as long as you follow each step in the appropriate order. This comprehensive free guide will help you to handle the malware removal and data recovery process correctly.
If you have any questions, comments, or are having troubles with following the instructions, please do not hesitate to contact us via the Ask Us section.
IMPORTANT! →
It is vital to eliminate malware infection from the computer fully before starting the data recovery process, otherwise ransomware might re-encrypt retrieved files from backups repeatedly.
Restore files using data recovery software
Since many users do not prepare proper data backups prior to being attacked by ransomware, they might often lose access to their files permanently. Paying criminals is also very risky, as they might not fulfill the promises and never send back the required decryption tool.
While this might sound terrible, not all is lost - data recovery software might be able to help you in some situations (it highly depends on the encryption algorithm used, whether ransomware managed to complete the programmed tasks, etc.). Since there are thousands of different ransomware strains, it is immediately impossible to tell whether third-party software will work for you.
Therefore, we suggest trying regardless of which ransomware attacked your computer. Before you begin, several pointers are important while dealing with this situation:
- Since the encrypted data on your computer might permanently be damaged by security or data recovery software, you should first make backups of it - use a USB flash drive or another storage.
- Only attempt to recover your files using this method after you perform a scan with anti-malware software.
Install data 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.
Find a working decryptor for your files
File encryption is a process that is similar to applying a password to a particular file or folder. However, from a technical point of view, encryption is fundamentally different due to its complexity. By using encryption, threat actors use a unique set of alphanumeric characters as a password that can not easily be deciphered if the process is performed correctly.
There are several algorithms that can be used to lock data (whether for good or bad reasons); for example, AES uses the symmetric method of encryption, meaning that the key used to lock and unlock files is the same. Unfortunately, it is only accessible to the attackers who hold it on a remote server - they ask for a payment in exchange for it. This simple principle is what allows ransomware authors to prosper in this illegal business.
While many high-profile ransomware strains such as Djvu or Dharma use immaculate encryption methods, there are plenty of failures that can be observed within the code of some novice malware developers. For example, the keys could be stored locally, which would allow users to regain access to their files without paying. In some cases, ransomware does not even encrypt files due to bugs, although victims might believe the opposite due to the ransom note that shows up right after the infection and data encryption is completed.
Therefore, regardless of which crypto-malware affects your files, you should try to find the relevant decryptor if such exists. Security researchers are in a constant battle against cybercriminals. In some cases, they manage to create a working decryption tool that would allow victims to recover files for free.
Once you have identified which ransomware you are affected by, you should check the following links for a decryptor:
- No More Ransom Project
- Free Ransomware Decryptors by Kaspersky
- Free Ransomware Decryption Tools from Emsisoft
- Avast decryptors
If you can't find a decryptor that works for you, you should try the alternative methods we list below. Additionally, it is worth mentioning that it sometimes takes years for a working decryption tool to be developed, so there are always hopes for the future.
Create data backups to avoid file loss in the future
Scan your system with anti-malware
If you are a victim of ransomware, you should employ anti-malware software for its removal. Some ransomware can self-destruct after the file encryption process is finished. Even in such cases, malware might leave various data-stealing modules or could operate in conjunction with other malicious programs on your device.
or can detect and eliminate all ransomware-related files, additional modules, along with other viruses that could be hiding on your system. The security software is really easy to use and does not require any prior IT knowledge to succeed in the malware removal process.
From our report of Jun 2021 · not reviewed since
Authors of Arena virus promise to decrypt files as soon as victims pay the ransom
Arena ransomware is a file-encrypting virus that is associated with the Dharma ransomware family.
Ransomware usually gets inside the system via malicious email and starts data encryption. Once this procedure is over, all files are locked with .id- .sindragosa@bigmir.net].arena file extension.
Following data encryption, the ransomware creates a FILES ENCRYPTED.txt document. It's a ransom note that provides information about data encryption. According to the crooks, the only data decryption option - paying the ransom . However, paying them might lead to money loss, so it is not recommended by security experts.
The message says that users have to contact cyber criminals:
Hackers obviously want the victim to buy Bitcoins and transfer them to their Bitcoin wallet address. Once it's done, the decryption key should be delivered to the victim. Unfortunately, the Zondervirus.nl team says that criminals cannot be trusted, so after paying the ransom, you might be left out with piles of encrypted files and no ways to decipher them.
Indeed, we receive victims' reports that hackers demanded even more money and did not receive a promised decryptor.
Warning: Therefore, do not pay the ransom no matter how important your files are to you.
From our report of Jun 2021 · not reviewed since
Hackers behind ransomware might scam you
Recently, we received information from a computer user who suffered from a virus attack.
After contacting developers via sindragosa@bigmir.net, he was asked to pay 500 euros for data recovery, but criminals asked to transfer the same sum of money two more times. However, after spending 1500 euros, a victim did not receive a decryption key.
Therefore, we want to warn that this malware is created only for swindling the money from the computer users. Instead of keeping their promise, hackers demand to pay for more money and leave you without a possibility to decrypt files. Thus, do not waste your time and money dealing with cyber criminals.
Instead of paying the ransom, concentrate on Arena ransomware removal. We strongly recommend using anti-malware tools to complete the task, as it is the easiest and safest way to eliminate the ransomware.
Ransomware removal is a complicated task that can be completed by advanced IT experts and malware analysts only, so you shouldn't attempt to remove the virus on your own.
Otherwise, such attempts can cause even more damage to your computer or convert your data into useless space-taking junk. To remove the virus, prepare your PC by rebooting it into Safe Mode with Networking (see instructions provided below) and use a software like or to identify and eliminate the threat.
From our report of Jun 2021 · not reviewed since
CryptoMix Arena malware's relation with Crysis ransomware group
The beginning of the new academic year supposedly brought new inspiration to malware developers as well.
Interestingly, this time, the developers of two well-known malware families – Crysis/Dharma and CryptoMix – presented quite a riddle for IT researchers.
They introduced the two latest versions of their root viruses. However, both of them append .arena file extension. Nonetheless, despite this feature, it is possible to tell a difference.
Crysis variant will attach .id- . .arena form of attachment. The CryptoMix version renames the file with a hexadecimal string containing the same extension.
The contact information is also different. Crysis variant indicates chivas@aolonline.top and macgregor@aolonline.top email addresses for contact information while CryptoMix variant presents ms.heisenberg@aol.com. What is more, the latest version is also much bothersome than the previous editions. It is programmed to delete shadow volume copies.
Besides the users' interface, the Crysis variant also launches the FILES ENCRYPTED.txt file with a brief note to contact the perpetrator. The rival version uses the _HELP_INSTRUCTION.TXT file to output ransom-demanding messages.
At the moment, there is no decryption available for both versions. You can restore the data with the assistance of backups . Whether you are infected with the Dharma variant or CryptoMix one, remove it and only then proceed to the data recovery procedure.
From our report of Jun 2021 · not reviewed since
Ransomware might attack from malicious email attachment
The infamous ransomware family is known to be distributed via malicious emails that deliver deceiving messages with a file attached to them.
Once the victim opens the infected file, Dharma roots into the computer system and destroys victim's files using a sophisticated encryption.
This procedure can be reversed, sadly, only using a decryption key. Without the decryption key, there is no way to restore files.
You shouldn't blame cyber security experts for not creating a decryption tool - encryption is an extremely secure method to protect files, so there is no wonder why it is used to keep military-grade secrets private. Usually, the one who encrypts files is the only one who knows how to decrypt them.
However, variants of Dharma ransomware can infiltrate your system alongside illegal downloads such as software cracks or with the help of exploit kits placed on compromised websites.
To protect your PC, use anti-malware software, create a backup and do not forget to get those software updates on time. You shouldn't delay Windows updates, no matter how annoying they might seem to you.
From our report of Jun 2021 · not reviewed since
Ransomware elimination steps
We have prepared a guide on how to remove Arena virus securely.
The first thing that you need to do is to choose the software you're going to use for removing the virus. Our recommendation is , and .
Please use trustworthy software for ransomware removal.
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
Arena ransomware could only hurt the files that had no second copy, and the signs (files that end in .arena 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.
Protect your privacy - employ a VPN
There are several ways how to make your online time more private - you can access an incognito tab.
However, there is no secret that even in this mode, you are tracked for advertising purposes. There is a way to add an extra layer of protection and create a completely anonymous web browsing practice with the help of VPN. This software reroutes traffic through different servers, thus leaving your IP address and geolocation in disguise.
Besides, it is based on a strict no-log policy, meaning that no data will be recorded, leaked, and available for both first and third parties. The combination of a secure web browser and VPN will let you browse the Internet without a feeling of being spied or targeted by criminals.
No backups? No problem. Use a data recovery tool
If you wonder how data loss can occur, you should not look any further for answers - human errors, malware attacks, hardware failures, power cuts, natural disasters, or even simple negligence.
In some cases, lost files are extremely important, and many straight out panic when such an unfortunate course of events happen. Due to this, you should always ensure that you prepare proper data backups on a regular basis.
If you were caught by surprise and did not have any backups to restore your files from, not everything is lost. is one of the leading file recovery solutions you can find on the market - it is likely to restore even lost emails or data located on an external device.
Questions about Arena ransomware
Is there a decryptor for .arena files?
That depends on the family behind the .arena extension, which this guide cannot confirm yet from the reports alone. Check No More Ransom and ID Ransomware with your ransom note and one encrypted file; they list families with free tools.
If none exists today, keep the encrypted files and a copy of the note on a separate drive, because decryptors are sometimes published months later after flaws are found or servers are seized. Never buy a decryptor from a website that is not the security company that made it.
Should I pay the ransom in _HELP_INSTRUCTION.TXT?
Not before you have tried everything else. Identify the family from _HELP_INSTRUCTION.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.
How do I open .arena files?
You cannot open them by renaming or by choosing another program. The .arena ending shows that Arena 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 Arena ransomware. Store the encrypted files on an external disk until then.
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 Arena ransomware get on my computer?
The way Arena 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 .arena 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 Arena ransomware steal my files or passwords?
We do not know yet. Nothing published so far shows data theft by Arena ransomware, but the only confirmed sign is files that end in .arena 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 Arena 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.
What does _HELP_INSTRUCTION.TXT tell me about the ransomware?
Quite a lot. The file name _HELP_INSTRUCTION.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 .arena spread to my other drives?
It can. Ransomware encrypts every drive and network share it can reach while it runs, so external disks, USB sticks and shared folders connected during the attack may also have files ending in .arena. Disconnect everything now, then check each device from a clean computer.
Do not plug a backup drive into the infected PC until the ransomware has been removed with an offline scan. Cloud folders such as OneDrive sync the encrypted versions, but they keep earlier versions you can usually restore.
Will Fortect remove Arena 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 Arena 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
- The Guardian - Technology: Don't pay WannaCry demands, cybersecurity experts say (read October 6, 2026)
- The Guardian - Technology: Hackers who targeted Ukraine clean out bitcoin ransom wallet (read October 6, 2026)
- ZonderVirus: ZonderVirus (read October 6, 2026)
- TecoReviews: The Importance of Plan B: Why Data Backups are Necessary (read October 6, 2026)
- CISA: StopRansomware (read October 6, 2026)