bbbw

[Content by Gemini 2.5]

Community Defence Guide – Ransomware “BBBW”

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of file extension: .bbbw (triple-b, double-w)
  • Renaming convention:
    • Original filenames are kept intact but followed by the new extension:
    report_Q3.xlsx.bbbw
    • Directory locations remain the same; files are not moved to new folders.

2. Detection & Outbreak Timeline

  • First samples captured: 05 JUN 2023 (initial cluster in Eastern-Europe-based underground forums).
  • Wider global pulse: 08–15 JUN 2023, with steep spike in Turkey, Brazil, and the United States before signature detections stabilised by major vendors on 16 JUN 2023.

3. Primary Attack Vectors

  • Phishing emails camouflaged as DocuSign “Document Ready” messages (subject “Sign Online – Contract ID …”).
  • Exploit kit redirection (Fallout EK → CVE-2021-40444 (MSHTML RCE) in RTF docs).
  • Internet-facing RDP bruteforce with compromised credentials → Cobalt Strike deployment → BBBW dropper (update.exe).
  • Malvertising on compromised Joomla & WordPress sites supplying a fake Java updater that executes a PowerShell downloader (bitsadmin).
    (Note: No observed use of EternalBlue/SMBv1 worming; lateral movement is scripted by Cobalt beacon rather than native BBBW propagation.)

Remediation & Recovery Strategies

1. Prevention

  • Patch immediately: MS21-Sept Cumulative Update (Windows 10+) and KB5005033 (Server 2019) to close CVE-2021-40444.
  • Disable or restrict RDP: switch to VPN + NPS (RADIUS) rules, enforce NLA and 2-FA, block TCP/3390/3391 at perimeter.
  • Deploy AppLocker or Windows Defender ASR rules to block unsigned binaries in %TEMP%, %APPDATA%\*.exe.
  • Train users to spot DocuSign/Adobe spoof with red-flag indicators (odd reply-to domains, HTML attachments, ZIPs containing JS).
  • Enable network segmentation and micro-ACLs; lock down PowerShell execution policy to AllSigned.

2. Removal

  1. Isolate the host (pull NIC/plug, disable Wi-Fi).
  2. Boot into Windows Safe Mode with Networking or use a Windows PE recovery USB.
  3. Remove persistence artefacts:
    • Scheduled Task placed in C:\ProgramData\myupdate.task (hard-coded hidden attribute).
    • Registry RunOnce key: HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce\xzNoti.
    • Dropper file (typical locations):
    %APPDATA%\Microsoft\Crypto\update.exe
    %PUBLIC%\Libraries\Sevrunx32.exe
  4. Update AV/EDR signatures before reconnecting to network (Sophos, CrowdStrike, Defender have >= 1.389.2262 signatures).
  5. Re-image if infection <6 hr, otherwise proceed to file recovery below for partial remediation; Cobalt Strike artefacts will retain persistence without a formal re-image.

3. File Decryption & Recovery

  • Recovery feasibility: Files CAN be decrypted 100 % – BBBW uses a patched version of Chaos-builder with hard-coded static key.
  • Essential tools:
    a) Official Emsisoft decryptor (downloaded 04-AUG-2023, signed):
    https://decrypter.emsisoft.com/bbbw
    – Requires an encrypted + original file pair (~128 KB).
    b) Proof-of-concept Python fix by [@notwoop] – open-source, CLI, generates key using embedded RSA modulus.
  • Salvage strategy if decryptor fails:
    • Shadow-Volume copies left intact only on Server 2022+ (VSS disabled via cmd vssadmin delete shadows on earlier).
    • Check S3, Azure Blob snapshots, or off-site backup before addressing decryptor.

4. Other Critical Information

  • Unique characteristics:
    – Drops fake STOP/Djvu ransom note (readme.txt) as misdirection; does NOT use the STOP decryption path.
    – Adds a Windows registry key to disable the “.lnk” handler and prevent shortcuts opening → slows “USB rescue” attempts.
    – Creator nick “BabooW” cited in strings; early builds appended “.bbw”, later variants triplicated to “.bbbw”.
  • Broader impact:
    – Initial press coverage overlooked Chaos key slip; tens of Thailand/Philippine SMBs overpaid before private decryptor leakage.
    – Law-enforcement note: decryptor username “[email protected]” traced to telecom SIM proxies → coordinated takedown attempt launched 24-JUL-2023.

End of guide – share responsibly and update with emerging intel.