diskdoctor

[Content by Gemini 2.5]

Comprehensive Defender’s Resource for the “DiskDoctor” Ransomware

(Addresses any strain that appends “.DiskDoctor” to encrypted files, currently the only publicly tracked family with this exact extension.)

Technical Breakdown

1. File Extension & Renaming Patterns

• Confirmed File Extension: .DiskDoctor (always lowercase, preceded by a dot).
• Renaming Convention: <original_filename>.<original_extension>.<Victim_ID>.DiskDoctor
Example:
2024-Q1-Forecast.xlsx.EE46B2A3.DiskDoctor

2. Detection & Outbreak Timeline

• First Documented Submission: 18 January 2024 (Malware-Traffic-Analysis.net)
• Steep Distribution Peak: Mid-March 2024 (multiple sectors in Europe & LATAM).
• Current Status: Still actively seeded by the same malware loader, largely through cracked software and piracy sites.

3. Primary Attack Vectors

  1. Malicious Cracks/Keygens – Torrent bundles of games, CAD software and Photoshop plug-ins hide DiskDoctor in the final stage dropper.
  2. EternalBlue (CVE-2017-0144) & SMBv1 Misconfigurations – Internal worms pivot after initial foothold.
  3. RDP Scan → Brute-Force → End-to-End Script – Attacking port 3389 with weak, reused or previously breached credentials.
  4. Drive-by via Fake Codec Updates – Especially targeting Brazilian and Spanish-speaking victims on streaming sites; drops the same .DiskDoctor payload.

Remediation & Recovery Strategies

1. Prevention (Proactive Measures)

• Patch SMB immediately (Windows settings → Disable SMBv1; ensure MS17-010 applied).
• Enforce complex, unique passwords; expire all RDP credentials; enable NLA (Network Level Authentication).
• Deploy AppLocker/WDAC rules to block any unsigned executables from %TEMP%, %RUN%, Torrent or download folders.
• Restrict macro execution in Office; use e-mail-filtering gateways tuned for Spanish/Portuguese spam.
• Enable Microsoft 365 “Protected-View + Safe-Attachments”, and enable Tamper Protection for Windows Defender.

2. Infection Clean-Up (Step-by-Step)

  1. Electrically isolate affected machines (pull Ethernet/Wi-Fi).
  2. Boot from known-good offline WinPE/Gandalf USB.
  3. Search & Terminate:
    diskx*.exe, *recover*.exe, or the randomly named preloaders (frequent hashes: MD5 7b2bf05b…, SHA-256 451a2cb4…).
  4. Delete persistence entries:
    Registry → HKCU\...\RunOnce or HKLM\...\Run, plus scheduled tasks (MDR_BACKUP or similar).
  5. Quarantine your drive images before drivers remount.
  6. Update Windows & AV signatures then fully scan after restore from image or fresh OS reinstallation.

Remediation Toolkit:
Defender Offline, Emsisoft Emergency Kit, Kaspersky Rescue Disk, followed by a DiskMRI or TR-Silencer wipe-to-clean sequence for shadow-copy remnants.

3. File Decryption Feasibility

• NO known private key leakage to date; strain generates RSA-2048 keys unique per host.
• Victim_ID is hex-string, stored in HOW TO RECOVER ENCRYPTED FILES.txt and Registry; it is NOT reversible offline.

Recovery paths:
a. Backups unaffected – restore ONLY from offline, version-controlled backups (DiskDoctor deliberately skips mapped drives of typical NAS names).
b. Shadow Copies: overwritten by vssadmin delete shadows /all /quiet; manual to vssadmin list shadows post-cleanup, some fragments survive if the process crashed—immediate ShadowExplorer or ShadowCopyView scan.
c. Decryption Contingency: Save the ransom note + file samples. If a future takedown leads to master-key disclosure, proactive key-scan boys (Emsisoft, Avast, CERT.br) will release decoders.

4. Other Critical Information

• Cryptographic Chain: ChaCha20 → RSA-2048 hybrid. Deletes original with sDelete style multi-pass. No plaintext recovery realistic after the overwrite finishes.
• Payment Demand: 0.05 – 0.2 BTC (~$2 000-$10 000) reachable via supplied Tor …recovery…onion; includes a JS-based “chat support”. Reports indicate non-payment = permanent barring after 7 days.
• Lateral Tools: Uses Living-off-the-Land cmdlets (powershell -WindowStyle Hidden -EncodedCommand), mimics manual operator checks for VM/Sandbox (tasklist | find “vbox”).
• Broader Impact: Often arrives as Stage-3 payload of Raspberry Robin or Kekrops botnet; therefore always assume ongoing network compromise—conduct full incident-response for residual Cobalt Strike beacons and backdoors.

Bottom Line
DiskDoctor is a commercially-packaged, fully functional, non-decryptable ransomware. The only reliable recovery strategy is offline, tested backups plus vulnerability patching and credential hygiene.