The MedusaLocker (.friends) Ransomware: A Definitive Forensic Recovery Guide

In our recovery lab today at Lockbit Decryptor, we isolated the MedusaLocker ransomware strain, identified by the variable .friends extension (e.g., .friends24, .friends50, .friends60) and the How_to_back_files.html note. Our forensic analysis confirms this is a sophisticated, enterprise-targeting ransomware operation. This strain employs a robust hybrid cryptosystem. Critically, our analysis indicates that this variant correctly implements the cryptographic primitives, and no known offline key vulnerabilities exist. Therefore, independent decryption without the actors’ private key is infeasible.

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EMERGENCY TRIAGE (THE GOLDEN HOUR)

If you encounter the .friends extension, execute these four protocols immediately to limit the blast radius:

1. Network Segmentation (TCP 445/3389): Immediately sever all SMB and RDP connections. Isolate affected VLANs at the switch level to prevent lateral movement and stop the encryption process on uninfected segments.
2. Hypervisor Isolation (Suspend VMs): For VMware ESXi and Hyper-V environments, suspend—do not power off—running virtual machines. This preserves the volatile memory state, allowing for the capture of raw memory dumps which may contain encryption keys.
3. Credential Flush (AD Reset): Assume total identity compromise. Force a password reset for all Domain Admin and Service accounts immediately, and revoke any persistent Kerberos tickets to block attacker re-entry.
4. Backup Air-Gapping: Physically disconnect or logically isolate all backup repositories (NAS, SAN, Tape). Verify that your offline snapshots are intact and have not been deleted or tampered with by the pre-encryption scripts.

Also read: The NBLock Black Ransomware Decryption: A Definitive Forensic Recovery Guide

THREAT PROFILE & FORENSICS

Technical Specifications:

File Extension Example: 1.jpg.friends24

Persistence Markers:

• Windows Services: Establishes persistence via a newly-installed service with a randomized name, executing the payload located in %ProgramData%.
• Scheduled Tasks: Utilizes schtasks.exe to create a task triggered by user logon, enhancing persistence across endpoint restarts.
• Virtualization Artifacts: The MedusaLocker source code includes modules for targeting ESXi, encrypting VMs stored on attached datastores.

Ransom Note Text:

Your personal ID:
-
YOUR COMPANY NETWORK HAS BEEN PENETRATED
Your files are safe! Only modified.(RSA+AES)
ANY ATTEMPT TO RESTORE YOUR FILES WITH THIRD-PARTY SOFTWARE WILL PERMANENTLY CORRUPT IT. DO NOT MODIFY ENCRYPTED FILES. DO NOT RENAME ENCRYPTED FILES.
No software available on internet can help you. We are the only ones able to solve your problem. We gathered highly confidential/personal data. These data are currently stored on a private server. This server will be immediately destroyed after your payment. If you decide to not pay, we will not release your data to public or re-seller. So you can expect your data to be publicly available in the near future.. We only seek money and our goal is not to damage your reputation or prevent your business from running. You will can send us 2-3 non-important files and we will decrypt it for free to prove we are able to give your files back.

Contact us for price and get decryption software.
email:

recovery1@salamati.vip

recovery1@amniyat.xyz

* To contact us, create a new free email account on the site: protonmail.com

IF YOU DON'T CONTACT US WITHIN 72 HOURS, PRICE WILL BE HIGHER.

* Tor-chat to always be in touch:

MATHEMATICAL VULNERABILITY ANALYSIS

MedusaLocker employs a cryptographically sound hybrid system. Per-file data is encrypted using AES-256 in CBC mode. The symmetric key $K_s$ is then wrapped using the actors’ RSA-2048 public key.

$$Ciphertext, IV = Enc_{AES-256-CBC}(K_s, P)$$
$$Wrapped_Key = Enc_{RSA-PKCS#1v1.5}(PK_{attacker}, K_s)$$

Cryptographic Implementation Assessment:
Our laboratory’s analysis concludes that no known implementation flaw exists in this MedusaLocker variant’s cryptographic construction. The use of a unique, random IV for each file and the robust AES-CBC mode eliminate common attack vectors. The RSA padding scheme, while older, is implemented correctly. The only path to decryption is possession of the unique, per-victim RSA private key held exclusively by the attackers. Therefore, decryption without actor cooperation is, with current technology, impossible.

IT ADMIN TOOLKIT (POWERSHELL AUDIT)

Deploy this script to conduct a thorough sweep for MedusaLocker-related IOCs across your fleet.

# Lockbit Decryptor Audit Script for MedusaLocker Variant
Write-Host "Initiating forensic sweep for MedusaLocker IOCs..." -ForegroundColor DarkBlue

# 1. Detect Files with the .friends* Extension
Get-ChildItem -Path C:\ -Recurse -Include "*.friends*" -ErrorAction SilentlyContinue -Depth 3 | 
    Group-Object { $_.Extension } | 
    Where-Object { $_.Count -gt 5 } | 
    ForEach-Object { Write-Host "Potential MedusaLocker Cluster Detected: '$($_.Name)' affecting $($_.Count) files." }

# 2. Locate Ransom Notes
Get-ChildItem -Path C:\ -Filter 'How_to_back_files.html' -Recurse -Force -ErrorAction SilentlyContinue -Depth 3 | 
Select-Object -First 100 FullName, LastWriteTimeUtc

# 3. Check for Persistence via Newly Created Services
Get-CimInstance -ClassName Win32_Service | Where-Object { 
    ($_.StartTime -gt (Get-Date).AddDays(-3)) -and 
    ($_.StartName -eq 'LocalSystem') -and 
    ($_.PathName -match '%ProgramData%')
} | Select-Object Name, DisplayName, PathName, StartMode

RECOVERY PATHWAYS & CTA

Strategic Recovery Roadmap:

• Backup Restoration (The Only Viable Path): Your only reliable path to recovery is restoring from verified, offline, immutable backups that were created prior to the infection window. All other options are non-viable.
• Data Breach Validation & Containment: The actors claim to have stolen data. Our forensic services can analyze network logs and system artifacts to validate or refute this claim, which is critical for regulatory and legal reporting obligations and for informing your stakeholders.
• Ignore the Actors’ Negotiations: Engaging with the provided Tor site or email address is a high-risk financial transaction with no guarantee of receiving a functional decryptor.
• FINAL RECOMMENDATION: Do not attempt to reboot the servers, negotiate with the actors, or use third-party “recovery” services. The only sound course of action is to accept the data loss on the infected systems and execute a comprehensive restoration from your secure backups. Contact Lockbit Decryptor for assistance with forensic preservation, data exfiltration analysis, and to be placed on a notification list should a future decryption solution become available.

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