basilisque locker

[Content by Gemini 2.5]

Comprehensive Resource: BASTILISQUE LOCKER Ransomware

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .basilisque
  • Renaming Convention: Victim files are renamed using the pattern [original_filename][original_extension].basilisque.
    Example: Budget2024.xlsx becomes Budget2024.xlsx.basilisque.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First sightings of Basilisque Locker occurred in mid–late Q2 2023, with active campaigns reported through the rest of 2023 and fresh outbreaks in early 2024.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Exploited Internet-Facing RDP: Uses validated guessed or brute-forced credentials over port 3389/TCP.
  2. Phishing E-mails with Malicious Macro Documents (.docm): Lure victims with “shipping notice,” “invoice,” or “quarterly report” attachments.
  3. Cobalt Strike Beacon Injection: After initial foothold, lateral movement and privilege escalation leverage Cobalt Strike tools delivered over SMB on ports 445/TCP and 139/TCP.
  4. Exploit of Vulnerabilities:
    • Fortinet FortiOS SSL-VPN (CVE-2022-42475)
    • Microsoft Exchange ProxyLogon (CVE-2021-26855)
    • Confluence OGNL Injection (CVE-2022-26134)

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
  1. Block TCP 3389 (RDP) on the edge unless absolutely required; mandate VPN + MFA.
  2. Disable Office macros from the internet via Group Policy.
  3. Use AppLocker or Windows Defender AV exclusions only after careful risk analysis.
  4. Patch CVE-2022-42475, CVE-2021-26855, CVE-2022-26134 before exposure.
  5. Enforce strong, unique passwords and enable MFA for all external services.
  6. Deploy network segmentation—limit SMB access between user broadcast domains.

2. Removal

  • Infection Cleanup (Step-by-Step):
  1. Isolate: Immediately disconnect affected hosts from network via firewall ACLs or physical pull.
  2. Identify and Kill Processes:
    • Check for basilisque_runner.exe, basilisque_service.exe, or beacon.exe.
    • Use Microsoft Sysinternals Process Explorer to locate and terminate with elevated privileges.
  3. Delete Persistence:
    • schtasks /delete /TN "BasilisqueUpdate"
    • Inspect HKLM\Software\Microsoft\Windows\CurrentVersion\Run and remove basilisque.exe or similar.
  4. Boot from Trusted Media: Use a live Linux distro (e.g., Trinity Rescue Kit) or WDO (Windows Defender Offline) to prevent self-protection by the malware.
  5. Run Endpoint Scanners:
    • Microsoft Defender offline scan (latest signatures).
    • ESET Online Scanner / Kaspersky Rescue Disk.
  6. Review Credentials: Assume compromise and reset domain admin, local admin, and service account passwords.

3. File Decryption & Recovery

  • Recovery Feasibility: As of 1 June 2024, NO free decryptor exists. The threat actor claims AES-256 with RSA-2048 key wrapping; no private key leaks have surfaced.
  • Non-Decryptable Filename(s): Files bearing .basilisque extension cannot currently be restored offline without the actor’s key.
  • Essential Tools/Patches:
  • Kape Kansa WIN-Forestrings for evidence collection before rebuild.
  • Sophos Central Intercept X or CrowdStrike Falcon with behavioral protection modules.
  • FortiOS 7.4.0 patch or latest stable version to close SSL-VPN gaps.
  • Exchange CU14 for ProxyLogon fixes.

4. Other Critical Information

  • Unique Characteristics:
  1. Multithreaded Encryption: Uses all logical cores in parallel, reducing encryption window to minutes on both SSDs and HDDs.
  2. Post-Encryption Reboot Abuse: Executes a forced reboot via Windows Error Recovery (shutdown /r /t 0) once all reachable volumes are encrypted, increasing psychological pressure.
  3. PRIORITY LIST: Targets C-level home directory and accounting sub-folders first using NTFS ACL enumeration, speeding up extortion leverage.
  • Broader Impact:
  • Organizations in manufacturing, healthcare, and financial services have seen both operational downtime (due to encrypted ERP/SAP systems) and reputation loss (due to stolen exfiltrated data dumps).
  • Average ransom demand is 4–7 BTC (~US$175 k–300 k), but threat actors also threaten to auction data on Tor marketplace “Emerald-Wall” if non-payment leads beyond two weeks.

Quick Action Checklist

  1. ✅ Confirm extension is .basilisque.
  2. ✅ Isolate hosts & networks.
  3. ✅ Search the No More Ransom portal for new decryptors.
  4. ✅ Preserve forensic evidence (RAM dumps, $MFT, Windows event logs) before formatting—data may aid CERT/LE collaboration.
  5. ✅ Use your incident response playbook to decide on ransom direction or full-rebuild strategy.

Stay vigilant—sign up with your national CERT and ransomware-specific threat-ops communities to watch for any upcoming private-key leaks or new decryptors targeting Basilisque Locker.