doctorhelp

[Content by Gemini 2.5]

Technical Breakdown of doctorhelp Ransomware:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .doctorhelp

  • Renaming Convention:
    After encryption, every file acquires the following structure:
    originalfilename.ext.original-extension.doctorhelp

    Examples:

  • Presentation.pptx → Presentation.pptx.doctorhelp

  • financials2024.xlsx → financials2024.xlsx.doctorhelp
    The malware also places a new file called README_DECRYPT-ID-<random-8-digits>.txt or doctorhelp.hta in every affected folder, on the desktop, and in every drive’s root.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First submissions to ID-Ransomware appeared on 20 March 2024; most rapid spread was observed between 21-25 March 2024, especially in Latin America and Eastern Europe.
    Malpedia & VirusTotal clusters show activity continuing through April 2024 with daily, iterative packing layers used to evade detection signatures.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Exploitation of Vulnerable VPN Gateways – Active exploitation of CVE-2023-46805, CVE-2024-21887 (Ivanti Connect Secure) and CVE-2023-34362 (MOVEit Transfer).
  2. Phishing E-mails – Attachments named “Scan_Invoice_[date].html.zip” that load a remote HTA (via mshta.exe).
  3. Weak or Leaked RDP Credentials – Attacks on TCP/3389 exposed to the Internet; routinely brute-forced with existing credential dumps.
  4. Exploit Kits via Adware Bundles – Trojanized free software installers that sideload the malware using living-off-the-land binaries (WMIC, rundll32.exe).
  5. SMBv1 & EternalBlue as Fallback – Where enabled, lateral movement uses the original NSA EternalBlue exploit for MS17-010 (chains the ransomware across domain-joined hosts in minutes).

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
  • Patch aggressively: Immediately upgrade or temporarily disable all Ivanti, MOVEit and RDP hosts until patched (check vendor advisories dated January-April 2024).
  • Disable SMBv1 via Policy / Registry; enforce SMB signature on servers and workstations.
  • E-mail & Browser Hardening: Use S/MIME or SPF+DKIM+DMARC, allowed-script-execution policies, and disable HTA/MHTML document execution in Windows.
  • Multi-Factor Authentication (MFA): Enforce on VPN, Remote Desktop Gateway (RDG), and privileged accounts.
  • Zero-Trust Network Access (ZTNA): Require device compliance before internal network access.
  • Backups: Follow 3-2-1 rule (3 copies, 2 media types, 1 offline), test restores quarterly.

2. Removal

  1. Isolate the compromised machine from the network (physically unplug or disable Wi-Fi).
  2. Identify Indicators:
  • Registry persistence under:
    HKCU\Software\Microsoft\Windows\CurrentVersion\Run → "doctorhelp"="C:\Users\<name>\AppData\Roaming\systemfile.exe"
  • Scheduled task WindowsSystemHealthCheck runs every 10 minutes from %APPDATA%\systemfile.exe.
  1. Boot into Safe Mode with Networking.
  2. Use a reputable anti-malware tool (Malwarebytes 2024 ThreatDown or Bitdefender). Ensure database version ≥ 1.0.104952 (contains doctorhelp sigs).
  3. Delete malicious entries and binaries, then reboot normally.
  4. Re-image if necessary—the malware drops Cobalt-Strike beacons and Mimikatz forks in memory.

3. File Decryption & Recovery

  • Recovery Feasibility: At the time of writing (mid-2024), there is no public decryption tool.
  • Recommended Steps:
  1. Verify backups (offline, immutable) first.
  2. Check ID-Ransomware weekly for new decryptors (some families receive exploits after law-enforcement server seizures).
  3. Do NOT re-use CUDA or SHA-based brute-forcers—doctorhelp uses a cryptographically secure Curve25519+ChaCha20 construction.
  4. If no backup: retain encrypted files, collect ransom notes (README_DECRYPT-ID-*.txt) and report to law enforcement for future key releases.

4. Other Critical Information

  • Unique Characteristics:
    – doctorhelp includes a Chat-over-Tor live support panel reachable via the Tor Browser (doctor2helpdhyea65.onion) which impersonates customer support to haggle ransoms.
    – Employs Windows Restart Manager APIs to terminate databases (SQL Server, MySQL) and Windows services listed in svcstop.txt inside its resource section.
    – Double-extortion: Before encryption it exfiltrates up to 2 GB via MegaSync and FTP; data is leaked on the BreachForge clearnet mirror if payment is not received within 14 days.
  • Broader Impact:
    – Hit at least 42 healthcare institutions in Colombia and Brazil by mid-April 2024, directly affecting diagnostic imaging and patient records.
    – US-CERT released Alert AA24-103A warning specifically against doctorhelp.

Bottom line: Doctorhelp is aggressively updated, doubles as an extortion group, and currently has no decryptor. Patch systems fervently, isolate backups, and assume credential or VPN compromise until proven otherwise.