1. Executive Summary: The Betelgeuse Threat

The ransomware landscape is heavily dominated by Ransomware-as-a-Service (RaaS) syndicates that constantly rebrand and iterate their malware to evade detection. Discovered by security researchers during recent telemetry analysis, the Betelgeuse ransomware is a highly destructive, newly identified variant operating under the infamous MedusaLocker umbrella. Much like its namesake—a massive red supergiant star—when Betelgeuse goes supernova inside an enterprise environment, the resulting collateral damage is vast and catastrophic.

Upon successfully breaching a corporate network, the Betelgeuse variant rapidly traverses local drives, mapped network shares, and centralized Storage Area Networks (SANs). It encrypts mission-critical data utilizing a complex, military-grade cryptographic algorithm. It visibly alters the environment by appending the .betelgeuse extension, followed by a specific numeric suffix (e.g., .betelgeuse35) to all impacted files. A critical system file originally named accounting_database.sql is instantly rendered useless as accounting_database.sql.betelgeuse35.

However, the encryption of internal files is only the final payload. Betelgeuse operates on a strict double-extortion model. Threat actors quietly exfiltrate vast quantities of internal, confidential, and proprietary business data to their private servers before deploying the encryption locker. They enforce a rigid 72-hour countdown to contact them before the ransom price increases. If payment is ultimately refused, they explicitly threaten to release the exfiltrated dataset to the public or sell it to data brokers, transforming an IT outage into a legally reportable data breach and compliance catastrophe.

This exhaustive, enterprise-grade playbook provides IT administrators, network engineers, and incident responders with a clear, actionable roadmap. Based on the NIST Incident Response framework, this guide details how to execute immediate containment, hunt for the remaining payload, navigate the extortion window, and execute a systemic recovery operation.

2. Threat Intelligence & MITRE ATT&CK Matrix

To successfully counter a ransomware deployment, defenders must understand the adversary’s technical footprint and operational methodology. Betelgeuse behaves identically to older MedusaLocker variants (like Developer, Gotcha, and Friends), relying heavily on stealth during the lateral movement phase and prioritizing the destruction of backups.

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

A ransomware infection is never a singular event; it is the culmination of a sophisticated kill chain. Understanding this progression is vital for identifying the initial point of compromise and closing the security gaps in your architecture.

1. Initial Compromise: MedusaLocker affiliates often gain entry through compromised credentials purchased from Initial Access Brokers (IABs) on the dark web, or via highly targeted spear-phishing campaigns delivering weaponized Microsoft Office documents, ZIP archives, or PDFs.
2. Lateral Movement & Reconnaissance: Once a single endpoint is breached, the malware remains dormant. The attackers manually explore the network, dumping credentials using tools like Mimikatz or Cobalt Strike, and mapping the Active Directory structure to identify Domain Controllers and centralized file servers.
3. Data Exfiltration (The Extortion Setup): Before any files are locked, the attackers identify sensitive directories—HR records, financial ledgers, client databases, and proprietary source code. This data is silently pushed to a private external server. This is the leverage they use for their extortion timeline.
4. Execution & Backup Destruction: Upon acquiring Domain Admin privileges, the threat actors deploy the ransomware payload globally (often via Group Policy or PsExec). Simultaneously, scripts are executed to wipe local backups and delete Volume Shadow Copies via vssadmin.exe, ensuring that standard IT recovery procedures are completely paralyzed.

4. The Complete Ransom Note Analysis

During an active incident, the RANSOM_NOTE.html file is a vital piece of forensic evidence. It provides the unique personal ID, the TOR negotiation portal, and the specific email addresses required by incident responders. Below is the complete text of the Betelgeuse HTML ransom note.

Your personal ID: – 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. 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 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] (For communication, create a Proton mail, Hotmail mail or Outlook) Tor chat address: – ATTENTION! All recovery offers on various websites are scams. You can only recover using the contacts in this note. Do not use any other platforms or messengers to recover your files; you can only do so by contacting the contacts in this note. Beware of middlemen, they come to us with your files, decrypt them and show themselves as if they decrypted them, take your money and disappear without giving you the tool! IF YOU DON’T CONTACT US WITHIN 72 HOURS, PRICE WILL BE HIGHER.

5. Phase 1: Detection & Threat Hunting

Upon discovering the .betelgeuse extension, rapid network-wide detection is required to identify all compromised assets and locate the initial payload. Security teams must sweep the environment to root out the executables.

Actionable PowerShell Threat Hunt

Deploy this PowerShell script via your centralized management console (e.g., SCCM, PDQ Deploy, or EDR Live Response) to audit endpoints for Betelgeuse indicators, including the destruction of shadow copies and the presence of the ransom notes:

# ==============================================================================
# Decryptors.org Incident Response Script: Betelgeuse Audit
# Target: Windows Endpoints (Run as Administrator)
# ==============================================================================

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

# 1. Check for encrypted file extensions in critical user directories
$testPaths = @("$env:USERPROFILE\Documents", "$env:USERPROFILE\Desktop", "C:\Data")
$infectionFound = $false

foreach ($path in $testPaths) {
    if (Test-Path $path) {
        # Using wildcard to catch .betelgeuse35, .betelgeuse10, etc.
        $encryptedFiles = Get-ChildItem -Path $path -Filter "*.betelgeuse*" -Recurse -ErrorAction SilentlyContinue
        if ($encryptedFiles.Count -gt 0) {
            Write-Warning "[!] CRITICAL: Encrypted .betelgeuse files detected in $path"
            $infectionFound = $true
        }
    }
}

# 2. Check for the presence of the specific ransom note
$ransomNote = Get-ChildItem -Path C:\ -Filter "RANSOM_NOTE.html" -Recurse -Depth 3 -ErrorAction SilentlyContinue

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

# 3. Check for suspicious VSS (Volume Shadow Copy) deletion events
try {
    $vssEvents = Get-WinEvent -LogName System -MaxEvents 200 -ErrorAction Stop | 
                 Where-Object {$_.Id -eq 7036 -and $_.Message -match "Volume Shadow Copy"}
    
    if ($vssEvents) {
        Write-Warning "[!] Warning: Shadow Copy service modifications detected in recent logs."
        Write-Warning "Threat actors likely executed VSS deletion commands to destroy local backups."
    }
} catch {
    Write-Output "[i] Could not parse Event Logs or no logs found."
}

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

7. Phase 3: Tiered Recovery & Decryption Strategies

Once absolute containment is verified and the initial access vector (such as compromised VPN credentials or a malicious payload drop) has been definitively patched, the organization can transition to the recovery phase. This must be executed with extreme caution.

Method 1: The Gold Standard - Restoring from Immutable Backups

The only mathematically guaranteed method for overcoming a Betelgeuse attack is a full architectural restoration from verified, immutable, or completely air-gapped backups.

• The "Clean Room" Rebuild: You cannot simply run an antivirus scan, delete the .betelgeuse files, and assume the server is safe. Threat actors leave persistent, hidden backdoors (such as Cobalt Strike beacons, scheduled tasks, or disguised remote monitoring tools). Affected hard drives must be entirely formatted. Perform a bare-metal OS reinstallation on all impacted hosts.
• Active Directory Cleansing & Credential Rotation: Assume all Active Directory credentials, including Domain Admins, are compromised. Force a global password reset for all users and service accounts. Crucially, reset the krbtgt account password twice to invalidate any Golden Tickets the attackers may have forged. Audit AD for any recently created, unauthorized administrator accounts.
• Sequenced Restoration: Follow a strict cross-platform recovery map. Restore Domain Controllers first in an isolated, firewalled VLAN to establish clean DNS and authentication. Once identity management is stable, restore critical database servers, and finally, end-user file shares.

Method 2: Cryptographic Response & Handling Extortion

If your organization lacks immutable backups, the situation is incredibly severe. Betelgeuse utilizes robust cryptography, meaning brute-forcing the encryption key is mathematically impossible with current technology without the attacker's private key.

The ransom note makes a very specific point to warn against "middlemen" who claim they can decrypt your files, stating they simply take your money, pay the hackers, and disappear. This is a half-truth designed by the hackers to ensure they get paid directly. While there are scam artists online, legitimate incident response firms negotiate on your behalf to lower the ransom significantly, ensure the safe transfer of decryption tools, and verify that the provided decryptor doesn't contain secondary malware.

If a legitimate decryptor becomes available through security research, or if an extortion payment is facilitated as a last resort to prevent the data leak, you must follow a strict, isolated automated decryption workflow:

1. Never decrypt on production hardware. The decryption tool provided by the threat actor may be bundled with secondary malware, data stealers, or logic bombs designed to trigger weeks later.
2. Clone the encrypted drives using professional forensic imaging software.
3. Mount the cloned drives on an isolated, air-gapped forensic workstation.
4. Run the decryption utility against the clone, never the original encrypted files.
5. Verify the file integrity of the decrypted data.
6. Scan the decrypted files with multiple next-generation EDR engines before moving them back to the newly rebuilt production environment.

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

Surviving a Betelgeuse attack is a grueling operational challenge. The response to the infection must serve as a catalyst for a comprehensive, zero-trust enterprise security overhaul. The ultimate goal is to move your IT environment from a reactive, vulnerable posture to a proactive, resilient architecture that can withstand future intrusions.

• Implement Immutable Storage Vaults: A modern Veeam 3-2-1-1 backup structure is strictly mandatory. You must incorporate immutable repositories (such as Linux Hardened Repositories, AWS S3 with Object Lock, or specific immutable SAN configurations). Immutable storage guarantees that once backup data is written, it cannot be modified, encrypted, or deleted for a specified retention period—even by a threat actor who has successfully stolen Domain Admin credentials and is actively executing VSS deletion scripts.
• Eradicate Public RDP & Enforce MFA: Remote Desktop Protocol (RDP) must never face the public internet. Access to the environment must require a VPN protected by strict multi-factor authentication (MFA), followed by a connection through a hardened jump-box or Privileged Access Management (PAM) solution. Ensure MFA is also enforced on all webmail and cloud-facing administrative portals.
• Deploy Endpoint Detection and Response (EDR): Legacy signature-based antivirus is entirely blind to modern, fileless ransomware techniques and credential dumping tools like Mimikatz. Deploy behavior-based EDR/XDR platforms configured to automatically isolate network adapters on hosts that attempt mass file modifications, execute suspicious commands, or exhibit lateral movement behaviors.
• Enforce the Principle of Least Privilege (PoLP) and Network Segmentation: Regular users must not have local administrator rights on their workstations. Furthermore, service accounts should be heavily restricted and denied interactive logon rights. Segment your network so that if an attacker compromises a standard user account via a phishing email, they are physically and logically blocked from traversing the network to reach critical financial databases or backup servers.

The Betelgeuse variant of MedusaLocker represents a highly sophisticated, financially motivated threat employing ruthless psychological extortion. Navigating this crisis requires a cool head, adherence to strict incident response frameworks, and a methodical approach to containment. Should this playbook highlight gaps in your current defensive posture, treat it as a mandate to immediately overhaul your enterprise IT infrastructure.