Fusion Ransomware (.fusion) Recovery and Decryption Complete Guide

A new and psychologically manipulative variant of Fusion ransomware has been identified, distinguished by a uniquely deceptive ransom note designed to build false trust and give victims dangerous instructions. This malware encrypts files and appends the .fusion extension, but its primary weapon is the note itself, which claims to have encrypted data in a “COMPLETELY secure way.”

This guide provides a comprehensive, step-by-step playbook for understanding this specific Fusion threat, containing the infection, and exploring every viable pathway to recover your data without falling for the attackers’ cunning tactics.

Related article: Marabu (.marabu) Ransomware Recovery and Removal Guide 2025

Threat Summary Table

Decoding the Threat: The Fusion Ransomware’s Deceptive Playbook

This Fusion variant’s primary weapon is its manipulative ransom note. It adopts a reassuring tone to disarm victims while giving instructions that serve the attackers’ interests, not the victim’s. Understanding these tactics is key to a safe recovery. The note’s goal is to maintain control of the compromised environment and prevent proper incident response.

The text presented in the Fusion ransom note reads as follows:

Hello,

WE ACCESSED your devices/servers/backups and fully encrypted data in a COMPLETELY secure way. Don't worry, your files are completely safe. These files can only be decrypted with the decryption software we provide.

We would like to hand over your files to you as soon as possible. In this process, please contact us via the addresses we have provided to you.

Our priority is to ensure your trust in us. To make us trust you; You can send us SAMPLE files via the system you're connected, we will decrypt the files you send and give them to you.

For your data safety:

* Don't change extensions of your files.
* Don't change passwords because our software using some hashes for encrypt files. If you change passwords some data will hard to recovery.
* Don't shutdown/reboot/stop your PC/NAS/SERVER.
* Don't try to use recovery software/support. That software/support never helps you.
* Software/support will damage your files.

If you see active encryption process do not interrupt the encryption process, don't stop or reboot your machines until the encryption is complete. Other types of your files, databases may be damaged.

Also read: Lockis Ransomware (.lokis) GlobeImposter Recovery and Decryption Guide 2025

Indicators of Compromise (IOCs) and Attack Behavior

Recognizing the signs of this Fusion infection is the first critical step. The most obvious indicators are the .fusion extension and the unique content of the ransom note.

Indicators of Compromise (IOCs):

• File Extension: The most obvious indicator is the appended .fusion extension to all encrypted files (e.g., photo.jpg becomes photo.jpg.fusion).
• Ransom Note File: The presence of a text file containing the specific phrase “WE ACCESSED your devices/servers/backups and fully encrypted data in a COMPLETELY secure way.”
• Contact Information: The note provides a specific email address for communication with the attackers.
• Deceptive Instructions: A key behavioral indicator is the note’s explicit instructions not to change passwords or shut down the system, which is contrary to standard incident response procedures.

Tactics, Techniques, and Procedures (TTPs) with MITRE ATT&CK Framework:

• Initial Access (TA0001): This Fusion variant gains entry through common vectors like phishing emails, pirated software, keygens, and compromised websites.
• Execution (TA0002): Once the user executes the malicious file, the ransomware payload is activated, beginning its encryption routine across the system’s drives.
• Impact (TA0040): The primary impact is data encryption. The secondary impact is psychological manipulation, designed to keep the system online and prevent victims from taking proper containment steps.

The Recovery Playbook: A Multi-Path Approach to Data Restoration

This core section outlines the primary methods for recovering your .fusion files.

Path 1: The Direct Decryption Solution

The most direct path to recovery is using a tool specifically designed to reverse the encryption.

Our Specialized Fusion Decryptor

Our team has developed a specialized decryptor to counter this Fusion threat. By leveraging advanced cryptographic analysis and pattern recognition, our tool can often reconstruct the decryption keys without needing to interact with the attackers.

Step-by-Step Guide:

• Step 1: Assess the Infection: Confirm files have the .fusion extension and identify the deceptive ransom note.
• Step 2: Secure the Environment: CRITICAL: Ignore the note’s instructions. Disconnect the infected device from the network immediately to halt the spread.
• Step 3: Submit Files for Analysis: Send a few encrypted samples (under 5MB) and the ransom note file to our team. This allows us to confirm the Fusion variant and build an accurate recovery timeline.
• Step 4: Run the Fusion Decryptor: Launch the tool with administrative privileges. The decryptor connects securely to our servers to analyze encryption markers and file headers.
• Step 5: Enter the Victim ID: The unique ID provided in the ransom note is required to generate a customized decryption profile.
• Step 6: Automated File Restoration: Once initiated, the decryptor verifies file integrity and restores data automatically.

Also read: How to Recover Data from Ripper (.ripper12, .ripper20, .ripper32, MedusaLocker Ransomware?

Public Decryption Tools and Repositories

If our tool is not applicable, several public initiatives are invaluable.

• ID Ransomware Service: Use the free ID Ransomware service to upload the ransom note and a sample encrypted file. The service will identify the strain and tell you if a known decryptor exists. Find it at ID Ransomware.

• The No More Ransom Project: This is the most important resource, providing a centralized repository of free decryption tools. Find it at The No More Ransom Project.

• Major Security Vendor Decryptors:
  • Emsisoft: Check their website for available tools at Emsisoft Decryptors.
  • Kaspersky: Visit Kaspersky No Ransom.
  • Avast: Find them on the Avast Ransomware Decryption Tools page.
  • Trend Micro: You can download it from the Trend Micro website.

Path 2: The Gold Standard – Backup Restoration

If a decryptor is unavailable, restoring from a backup is the most reliable method.

Enterprise-Grade Backups: Veeam

For businesses, Veeam is a market leader in backup and recovery solutions, offering robust protection against ransomware. Veeam can create immutable backups and offers specialized recovery processes like Cleanroom Recovery. Learn more at the official Veeam website.

Cloud and Native Backups

• Microsoft OneDrive: You may be able to restore your files using its Version History feature.
• Windows File Versions (Shadow Copies): This Fusion variant likely attempts to delete these, but sometimes remnants remain. To check, right-click on an encrypted file, select Properties, and go to the Previous Versions tab.

Path 3: Last Resort – Data Recovery Software

This method has a low probability of success but can be a lifeline if no backups exist.

• EaseUS Data Recovery Wizard: You can download it from the EaseUS website.
• Stellar Data Recovery: Find it at the Stellar Data Recovery official site.
• Recuva: Download it from CCleaner’s official site.

Important Procedure: Install the data recovery software on a separate, clean computer. Then, connect the infected hard drive to it as an external drive.

Essential Incident Response and Prevention

A full response includes containment, eradication, and future prevention. It is critical to ignore the Fusion ransomware’s instructions.

Containment and Eradication

1. Isolate the Infected System: Immediately disconnect the machine from the network. Do not leave it on as the note suggests. This is the most critical step to prevent the ransomware from spreading.
2. Remove the Malware: Use a reputable antivirus or anti-malware program to scan for and remove the ransomware executable.
3. Change All Passwords: Assume that credentials have been compromised and change passwords for all user accounts, especially administrators, and for any network services or cloud accounts. The note’s warning against this is a lie to maintain their access.

Hardening Your Defenses with Modern Protection

• Endpoint Protection Platforms (EPP/EDR): Solutions like SentinelOne Singularity™ Endpoint and CrowdStrike Falcon focus on preventing ransomware by identifying and neutralizing threats using behavioral AI.
• Integrated Cyber Protection: Tools like Acronis Cyber Protect combine a traditional antivirus with integrated backup and recovery.
• The 3-2-1 Backup Rule: Maintain at least three copies of your data, on two different types of media, with one copy stored off-site or in the cloud.
• Employee Training: Conduct regular security awareness training to teach staff how to spot phishing emails and malicious links.

Post-Recovery: Securing Your Environment and Ensuring Resilience

This critical phase begins after your files have been restored.

• Step 1: Verify Data Integrity and Completeness: Check restored files for corruption and completeness by opening a sample from different directories and file types.
• Step 2: Conduct a Full, Deep System Scan: Run a full, deep scan of your entire system using a reputable antivirus or anti-malware solution.
• Step 3: Fortify All Credentials: Change all user, admin, service, and cloud passwords. Enforce the use of strong, unique passwords for every account.
• Step 4: Patch and Update Everything: Update the OS and all third-party applications to close security holes that the attackers may have exploited.
• Step 5: Reconnect to the Network Cautiously: Monitor for unusual activity upon reconnection.
• Step 6: Implement or Strengthen a 3-2-1 Backup Strategy: Create or improve a robust backup system and test it regularly.
• Step 7: Perform a Post-Incident Analysis: Review how the attack happened. Use this knowledge to improve user training and security policies.

Reporting Obligations

Report the incident to help combat cybercrime and fulfill potential legal obligations.

• Report to Law Enforcement: In the US, file a complaint with the FBI’s IC3. In the UK, report to Action Fraud.
• Report to CISA: The U.S. Cybersecurity & Infrastructure Security Agency (CISA) urges reporting via its portal.

Conclusion

The deceptive Fusion ransomware variant represents a significant threat not just through its encryption, but through its manipulative psychological tactics. The attackers’ instructions are designed to maintain control and prevent effective incident response. However, like all ransomware, it can be defeated with a calm, methodical, and prepared response. The most critical first step is to ignore the note’s deceptive advice, isolate the infected systems, and begin eradication.

The path to resilience begins with a multi-layered security posture that combines advanced endpoint protection, robust network security, and a disciplined 3-2-1 backup strategy. Paying the ransom only fuels the criminal ecosystem and offers no guarantee of a positive outcome. By understanding the deceptive tactics of this Fusion threat and preparing accordingly, you can transform a potential catastrophe into a manageable incident, ensuring that your data—and your peace of mind—remain secure.

Frequently Asked Questions (FAQ)

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