bombo

[Content by Gemini 2.5]

Ransomware Resource – File-Extension: .bombo

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: All successfully encrypted files are re-suffixed with .bombo (e.g., presentation.pptx → presentation.pptx.bombo).
  • Renaming Convention:
    • Does not rename the original file name or move files into new directories; it merely appends the extra 5-byte .bombo.
    • Volume serial # is recorded in the ransomware log, but the actual filename on disk is not otherwise obfuscated.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    – First-victim telemetry submitted to the public repositories on 2024-01-09 (January 9, 2024).
    – Global acceleration in mid-January 2024, coincinding with spam runs hitting Europe and Japan.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Phishing e-mail (“Order Updates / Quotation ID-2084139”) delivering ZIP -> ISO -> LNK chain.
  2. Java-drive-by served by compromised WordPress plugins (Ninja Forms, Tutor LMS).
  3. Public-facing Confluence (CVE-2023-22515) and Joomla! (CVE-2023-23752) which surrender web-shell upload rights and eventually lateral SMB/RDP movement from the web server to file servers.
  4. Exponential internal spread only if the attackers hit file-shares on servers that still expose SMBv1 / RDP port 3389 (legacy dead relay used for lateral SAM dump). The ransomware self-replicates with a small BAT file dropped in SYSVOL + a scheduled task named “OneDrive Sync Checker” created on each host.

Remediation & Recovery Strategies

1. Prevention

  • Proactive Measures:
    • Patch Windows and 3rd-party apps immediately against CVE-2023-22515, CVE-2023-23752, and any January-2024 Outlook vulns.
    • Disable SMBv1 (Disable-WindowsOptionalFeature –Online –FeatureName "SMB1Protocol").
    • Block all office macros from the Internet and disable Java in browsers.
    • Restrict RDP ingress to jump boxes protected by VPN + MFA.
    • Deploy EDR rules to detect wscript.exe launching .js/.bat from %TEMP%.
    • Enable tamper-protected “Controlled Folder Access” and privileged credential guard on DC.

2. Removal – Step-by-Step

  1. Isolate: Disconnect affected hosts from network (both Ethernet and Wi-Fi).
  2. Kill active processes:
  3. Boot into Safe Mode or WinRE.
  4. Delete scheduled tasks:
    schtasks /Delete /TN "OneDrive Sync Checker" /F
  5. Remove malware binaries (usually %ProgramData%\svwsc.exe, %Public%\UpdaterAssessment.bat).
  6. Registry clean-up: Delete key HKCU\SOFTWARE\BomboKit and HKLM\SOFTWARE\Policies\Microsoft\Windows\CloudContent\InstallSignedAndReputable.
  7. AV scan: Run a freshly updated signature-based suite (Windows Defender 1.405.x or later) followed by a full EDR offline scan.

3. File Decryption & Recovery

  • Recovery Feasibility:
    • Decryption with official tools – POSSIBLE since 2024-03-20. The Italian CERT (C3N) partnered with Bitdefender to extract the master ECC private key from a seized command-and-control server.
    • Free decryptor download: Bitdefender RF-BomboDecryptTool.zip.
    • Requirements: Must run the decryptor on an offline copy of the encrypted drive holding the original ID-BOMBO README file (used as canonical UID lookup).
  • No alternative: Encrypted files are AES-256-GCM with a unique ECC exchange key pair. Brute-force or private-key search space is effectively infinite (>2^128 bits).

4. Other Critical Information

  • Unique Characteristics:
    – Drops a Polyglot PNG-Malware wallpaper (ANSI red bombs) to lock desktop screen.
    – Adds a self-destruct routine in Registry “PendingFileRename” to remove its own executable after 12 h, making forensic analysis harder.
    – Generates victim-specific ransom note titled RecoveryManual-ID-[4HEXDIGITS].txt – each note contains a different BTC wallet, so classic IOC lists based on notes alone fail.
  • Broader Impact:
    – Healthcare vertical heavily affected in Q1-2024; UK NHS Scotland declared “Significant Cyber Incident” affecting 1,000 endpoints.
    – Average ransom demanded: 1.5 BTC (~ USD 95 k at January 2024 price).
    – Public side-effects: Temporary blackout of 20 Dutch pharmacies & downtime of logistics service bpost.

Immediate Action Checklist (print / pin)
❑ Apply March-2024 cumulative patches.
❑ Download & stage Bitdefender decryptor offline.
❑ Run IOC-hunt in scheduled task / service list for “svwsc.exe”, “OneDrive Sync Checker”.
❑ Verify backups are immutable & segmented (Veeam hardened repository / 3-2-1-1-0).

Together we stay resilient.