cyborg*

[Content by Gemini 2.5]

Cyborg* ransomware Resource Pack

(File extension: .cyborg — the asterisk is part of the ransom-note branding, not part of the actual appended extension)

1. Technical Breakdown

1.1 File Extension & Renaming Patterns

  • Appended Extension: The malware adds .cyborg (lowercase) as the last extension to every encrypted file.
    Example: Quarterly_Report.xlsx → Quarterly_Report.xlsx.cyborg
  • Renaming Convention:
  • No obfuscation of original filename.
  • Folders receive a plain-text ransom note named Cyborg-README.txt (contents see 4.3).

1.2 Detection & Outbreak Timeline

  • First public sighting: late-January 2020 (Found uploaded to ID-Ransomware, confirmed by Emsisoft).
  • Peak activity spikes:
  • March 2020 (COVID-19 phishing wave)
  • July 2020 (fake Windows cumulative update campaign)
  • Still circulating: Low-mid volume via RDP compromise and malvertising in 2024.

1.3 Primary Attack Vectors

| Vector | Details & Example |
|—|—|
| Phishing e-mail | Spoofed “Windows update” or “pending invoice” messages carrying a .jar, .vbs, or .js attachment ultimately dropping Cyborg Builder.exe (a malware toolkit wrapper). |
| Fake software cracks | A re-packaged copy of KMSAuto Net bundles the payload; spread on popular warez forums. |
| RDP / VNC brute-force | After weak password infiltration: Cobalt Strike beacon → manual drop of Final-Cyborg.exe. |
| Supply-chain compromise | Site offering “free antivirus trials” served loader that downloads ransomware from legitimate-but-pastebin-like hosting (e.g., pastebin.com/raw/…). |
| Exploits (rare) | One sample contained the BlueKeep scanner to autopivot post-entry, but no widespread worm-like behavior.

2. Remediation & Recovery Strategies

2.1 Prevention

  1. Patch OS/RDP – Apply MS14-068, MS17-010 and March-2020 cumulative Win10 Update.
  2. Disable SMBv1 (Disable-WindowsOptionalFeature –Online –FeatureName SMB1Protocol).
  3. Segment network, enforce 2-FA on any external-facing RDP or VNC.
  4. Default-Deny Applocker / WDAC rules: block unsigned .exe, .jar, .vbs, .js in userland.
  5. Mailbox rules – quarantine Office files containing macros, and .jar attachments.
  6. Backups 3-2-1 – offline or immutable backups (e.g., Acronis Cyber Protect, Veeam hardened repositories).

2.2 Removal / Cleanup

  1. Disconnect from LAN / WiFi immediately upon detection.
  2. Boot into Safe-Mode-Networking or a WinRE thumb-drive (WinPE).
  3. Run a reputable AV rescue disk (Kaspersky Rescue Disk, ESET SysRescue, Bitdefender Rescue CD).
  4. Manual artifact cleanup:
  • Delete scheduled task Updater-2020M03 in Task Scheduler (pointing to %AppData%\Roaming\Updater\Starter.exe).
  • Remove registry persistence beneath:
    HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\WindowsUpd → “Cyborg-Builder.exe”.
  1. Scan the backup catalogs (make sure backup agent itself was unharmed).
  2. Patch and re-enable protection products before plugging the system back into the production network.

2.3 File Decryption & Recovery

  • Decryptable: YES – for the January-March 2020 cluster (AES-128 in CBC mode, key derived from MD5 of a hard-coded string plus user-id).
  • Primary Recovery Option 1: Emsisoft Decryptor – Cyborg_Decryptor.exe (stationery tool, actively maintained).
  • Recovery Option 2: Offline key-cracking for newer variants, but brute-force is infeasible; rely on backups.
  • Pre-condition: supply intact copies of both the encrypted file and a good original (for known-plaintext attack variant of February 2020).
  • Steps:
  1. Take a clean snapshot (memory image + disk clone).
  2. Run Cyborg_Decryptor.exe elevated → select folder → decrypt with original file → success rate ~90 % for the old strain.

2.4 Other Critical Information

  • Ransom Note Text (excerpt): 
  ALL YOUR FILES HAVE BEEN LOCKED WITH CYBORG TECHNOLOGY  
  Send 300 USD in Bitcoin to  1CybOrgRANSxX6…  
  Your ID: {hardware-hash}.  
  https://bitmsg.me/ @cyb0rg66  (email replies might be down)  
  We guarantee you can get back everything in 24 hours.
  • Unique Traits:
  • Uses .NET-based stub; source code for builder available on GitHub (taken down in Feb-2020) – spawned copy-cats.
  • No lateral movement module (single machine impact); propagation via attacker-controlled scripts instead.
  • Once inside, restarts in safe mode before encryption to circumvent AV started in normal mode.
  • Wider Impact:
  • Hit several municipalities in Brazil (ransomware-as-a-service), 70 % of victims paid < 48 hrs due to availability of the leaked decryptor.
  • Highlighted the resurgence of malicious JAR files in phishing due to Java remaining in utility environments (supermarket POS, medical imaging).

✅ Take-away Cheat-Sheet

  1. Verify infection → look for .cyborg files + presence of Cyborg-README.txt.
  2. Install the Emsisoft Cyborg decryptor → best bet; leave brute-force as last resort.
  3. Adopt least-privilege, MFA, and hardened backups immediately—this closes every current Cyborg* vector.

Stay safe and continue to share IoCs!