1. Executive Summary: The Rust-Based MedusaLocker3 Threat

The ransomware landscape is undergoing a significant architectural shift, with major threat actor groups rewriting their payloads in modern, cross-platform languages. Discovered actively targeting enterprise environments, the MedusaLocker3 (Version 5) ransomware represents a highly sophisticated evolution of the MedusaLocker family. Entirely rewritten in Rust, this variant is designed for maximum execution speed, deep evasion of traditional antivirus signatures, and explicit targeting of critical database infrastructure.

Upon breaching a corporate network, MedusaLocker3 rapidly seeks out Microsoft SQL Server environments. It stops active database services to unlock the files and encrypts mission-critical data, appending the .spider extension followed by a localized numerical identifier (e.g., .spider62). A primary Master Data File originally named inventory.mdf is instantly rendered useless as inventory.mdf.spider62.

Crucially, forensic analysis of the encrypted .spider62 files reveals a distinct cryptographic signature: the malware overwrites the original magic bytes (file headers) with the hex sequence 52 41 57 52 02 02, which translates to ASCII “RAWR”. This header replacement severely complicates standard data recovery efforts. In scenarios where no backups are available, the organization faces a critical extortion event orchestrated via [email protected] and [email protected]. This playbook provides IT administrators, database administrators (DBAs), and incident responders with a clear roadmap to contain the active breach, evaluate the “RAWR” header damage, and navigate the high-stakes extortion threat.

2. Threat Intelligence & Technical Specifications

To successfully counter a MedusaLocker3 deployment, defenders must understand the adversary’s technical footprint. The shift to Rust makes the binary highly resistant to traditional reverse engineering and significantly accelerates the encryption process.

3. Anatomy of a Database Attack (The Kill Chain)

A ransomware infection targeting a database server is rarely accidental; MedusaLocker3 operators specifically hunt for high-value targets to maximize their extortion leverage.

4. The Complete Ransom Note Analysis

During an active incident, the RANSOM_NOTE.html file is a vital piece of forensic evidence. Based on incident response telemetry, below is the reconstructed text typically found in the ransom note left by the MedusaLocker3 operators.

YOUR COMPANY NETWORK HAS BEEN PENETRATED ANY ATTEMPT TO RESTORE YOUR FILES WITH THIRD-PARTY SOFTWARE WILL PERMANENTLY CORRUPT IT. DO NOT MODIFY ENCRYPTED FILES. DO NOT RENAME ENCRYPTED FILES. 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 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: [email protected] [email protected] (To contact us, please create a Proton or Hotmail account. Don’t use Gmail, as your messages will end up in spam.)

5. Phase 1: Detection & Threat Hunting

Security teams must sweep the environment for the .spider extension family, the specific ransom notes, and audit the status of the VSS and SQL services.

Actionable PowerShell Threat Hunt

Deploy this PowerShell script via your centralized management console (e.g., SCCM or EDR Live Response) to audit servers for MedusaLocker3 indicators:

# ==============================================================================
# Decryptors.org Incident Response Script: MedusaLocker3 (.spider) Audit
# Target: Windows Servers / SQL Environments (Run as Administrator)
# ==============================================================================

Write-Host "Starting MedusaLocker3 Network Audit..." -ForegroundColor Cyan

$infectionFound =$false

# 1. Check for encrypted file extensions targeting SQL and user directories
$testPaths = @("C:\Program Files\Microsoft SQL Server", "$env:USERPROFILE\Documents", "D:\Data")

foreach ($path in$testPaths) {
    if (Test-Path $path) {
        # Catching the .spider family (e.g., .spider62)
        $files = Get-ChildItem -Path$path -Filter "*.spider*" -Recurse -ErrorAction SilentlyContinue
        if ($files.Count -gt 0) {
            Write-Warning "[!] CRITICAL: Encrypted .spider files detected in $path"
            $infectionFound =$true
        }
    }
}

# 2. Check for the presence of the specific ransom note
$ransomNotes = Get-ChildItem -Path C:\ -Filter "RANSOM_NOTE.html" -Recurse -Depth 4 -ErrorAction SilentlyContinue

if ($ransomNotes) {
    Write-Warning "[!] CRITICAL: MedusaLocker ransom note (RANSOM_NOTE.html) discovered."
    $infectionFound =$true
}

# 3. Check the status of the Volume Shadow Copy (VSS) Service
try {
    $vssService = Get-Service -Name VSS -ErrorAction SilentlyContinue
    if ($vssService.Status -eq 'Stopped' -and$vssService.StartType -eq 'Disabled') {
        Write-Warning "[!] CRITICAL: Volume Shadow Copy service (VSS) has been explicitly disabled!"
        Write-Warning "This is a primary indicator of defense evasion by the threat actors."
    }
} catch {
    Write-Output "[i] Could not verify VSS service state."
}

if ($infectionFound) {
    Write-Warning ">>> IMMEDIATE SERVER ISOLATION REQUIRED. DO NOT REBOOT. <<<"
} else {
    Write-Output "[i] No immediate signs of MedusaLocker3 infection on this endpoint."
}

7. Phase 3: SQL Server Database Triage & Recovery

Recovering from a database-centric ransomware attack with no available backups requires highly specialized techniques. Standard file recovery does not apply to complex relational databases whose headers have been overwritten with the "RAWR" signature.

Method 1: Forensic Database Repair (Partial Encryption Extraction)

MedusaLocker3 utilizes intermittent encryption for speed. While the header is destroyed (replaced by 52 41 57 52 02 02), the vast majority of the actual table data deep within the multi-gigabyte .mdf file may still be perfectly intact in plaintext.

• Do Not Use Standard Repair Tools: Running standard Windows file repair tools (or `DBCC CHECKDB` on a renamed file) will fail entirely because the SQL engine cannot read the "RAWR" magic bytes.
• Forensic Data Carving: Specialized SQL database repair experts can bypass the encrypted header, scan the raw hexadecimal structure of the file, and extract the unencrypted tables, schemas, and rows directly. This data is then migrated into a clean, newly built database instance. This is often the most cost-effective method when no backups exist.

Method 2: Cryptographic Response & Handling Extortion

If forensic data carving yields insufficient data (e.g., the ransomware encrypted a high percentage of the file blocks), engaging the threat actors is the only remaining option to retrieve the master private session key.

Never negotiate alone. Allow professional incident response firms to handle communication with [email protected]. They will:

• Utilize the "2-3 free test files" offer to definitively prove the attacker holds the working key.
• Negotiate the ransom demand down significantly from the initial asking price.
• Verify the provided decryptor executable in a secure sandbox to ensure it does not contain secondary malware payloads before running it on your cloned data.

8. Phase 4: Post-Incident Hardening & Server Resilience

Surviving a MedusaLocker3 attack without backups is a catastrophic operational event. The response to this infection must serve as a mandate for a comprehensive enterprise security overhaul.

• Eradicate Public RDP Exposure: Remote Desktop Protocol (RDP) must never face the public internet. This is the primary entry point for MedusaLocker affiliates. Access to the environment must require a VPN protected by strict multi-factor authentication (MFA).
• Isolate SQL Servers from the Internet: Database servers should never be directly accessible from the public internet. Ensure port 1433 is blocked at the perimeter firewall.
• Implement Immutable Storage Vaults: You must immediately deploy a modern Veeam 3-2-1-1 backup structure incorporating immutable repositories (such as Linux Hardened Repositories or AWS S3 with Object Lock). Immutable storage guarantees that once backup data is written, it cannot be modified, encrypted, or deleted—even if an attacker explicitly disables the VSS service.
• Deploy Endpoint Detection and Response (EDR): Deploy behavior-based EDR/XDR platforms configured to automatically isolate network adapters on servers that attempt mass file modifications or exhibit lateral movement behaviors.

The MedusaLocker3 (.spider62) ransomware represents a highly destructive, Rust-based threat focused explicitly on critical database infrastructure and defense evasion. Navigating a zero-backup crisis requires a cool head, adherence to strict incident response frameworks, and specialized forensic database triage. Should this playbook highlight gaps in your current defensive posture, treat it as a mandate to immediately overhaul your enterprise IT architecture.