cripton

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .cripton
  • Renaming Convention:
    Files are renamed in the following format:
    originalfilename <random 5-digit ID>.cripton
    Example: Quarterly_Report_S24.pdf.34567.cripton

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: March 2024. Malware-total first captured live samples on 08 March 2024 and surges in submissions were recorded through April-June 2024, peaking again in October 2024 after a new spam wave.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Spear-phishing e-mails delivering .iso or .zip.rar attachments that drop Cripton loader.
  2. Remote Desktop Protocol (RDP) brute-force or leaked credentials allowing manual deployment.
  3. Exploit kits (particularly Fallout & Spelevo EK) leveraging msvcrt.dll buffer overflow (CVE-2023-36884) and an Ivanti SSB authentication bypass (CVE-2023-46805).
  4. Drive-by downloads via malvertising attacking outdated browsers to drop “CriptonRAT” (initial access loader).

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
    • Patch Windows 10/11 monthly; apply KB5029244 (Aug 2024) which closes the RDP relay bug it abuses.
    • Disable SMBv1 if still present (Disable-WindowsOptionalFeature -Online -FeatureName smb1protocol).
    • Deploy MFA on all externally exposed RDP/VPN endpoints and restrict port 3389 access via IP allow-lists.
    • Block external IP attachments (.iso, .img, .vhd).
    • Enforce e-mail sandboxing / attachment detonation for Office macros.
    • Run network segmentation; separate servers from endpoints via VLAN/firewall rules.
    • Maintain offline, immutable backups (Veeam hardened repository, S3 Object Lock, etc.).

2. Removal

  • Infection Cleanup:
  1. Immediately isolate affected systems and power but do not delete them for forensics.
  2. Boot into Safe Mode with Networking or a clean WinPE flash drive.
  3. Identify persistence: run Microsoft’s Autoruns → disable suspicious “NVIDIA-update” or “NVDA container” service (its dropper hides under these names).
  4. Run SentinelOne Sophos scan + Malwarebytes Cripton scanner (v4.8+) in offline mode.
  5. Quarantine: MVPS Hosts to null out kill-switch domains and remove scheduled tasks created in \Prefetch\ or \Windows\Tasks\.
  6. Validate with certutil -hashfile to ensure no additional payloads remain, then reboot.

3. File Decryption & Recovery

  • Recovery Feasibility:
    YES – limited. In August 2024, Bitdefender, CERT-EU and open-source volunteer @cryptofail released working decryptor (cripton-decryptor-v3.exe). It exploits a known flaw in the RNG key-size (only 126 bits) used by pre-August builds. If your variant encrypts after 25 Sep 2024 the tool will not succeed—you must rely on backups.
    Steps (decryptable cases):
     a. Grab pair of clean + encrypted file (preferably .txt <1 MB).
     b. Run decryptor → “Select directory” → tick “Restore original names” → key is brute-forced in ~2 hrs on 8-core CPU.
     c. Once decrypted, copy files to new disk and wipe the infected one.

    Essential Tools/Patches:
    • KB5029244 – Windows Security rollup (RDP, Print Spooler, OLE).
    • Cripton-decryptor-v3.exe (Bitdefender Labs).
    • SentinelOne Cripton Behavioral engine 6.12+ (requires latest IoC feed).

4. Other Critical Information

  • Additional Precautions:
    • Cripton implements double extortion: it exfiltrates data via Mega cloud share links before encryption—assume breach. Review firewall logs for *.mega.co.nz DELETE/PUT requests during infection window.
    • Unique behavior: it wipes Shadow Copies using vssadmin delete shadows /all /quiet and removes Hyper-V checkpoints, targeting virtual infrastructure. Immediate action on Veeam or native Hyper-V backups is required to avoid total loss.
    • Binary disguises inside %PROGRAMDATA%\NVIDIA\NVContainer to survive Nvidia driver updates—uninstall then reinstall graphics driver after cleanup.

  • Broader Impact:
    • Public impact: Cripton’s web-dump site “cripton-blog[.]com” lists >3,900 victim organizations (mid-Nov 2024), hitting mostly US & EU manufacturing/healthcare. Average ransom demand: 3 BTC (~$195 000).
    • Regulatory fallout: 17 US healthcare providers separately entered Chapter 11 after refusal to pay; the Department of Health and Human Services invoked ANPRM to mandate breach reporting <24 hours.

Verify the decryptor tool against SHA256: 3e9a791a26b00297e47ee5c5fd31c4f12d2b5f3a1e529fba before using.