bbbr

[Content by Gemini 2.5]

BBBR Ransomware – Community-Friendly Defense & Recovery Guide

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension:
    .bbbr – added after the original file extension (e.g., Balance-Sheet.xlsx.bbbr).

  • Renaming Convention:
    The malware keeps the original filename + extension unchanged and concatenates “.bbbr” as a final suffix. Directory contents therefore still reveal what each file was before encryption.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    First samples were uploaded to public malware repositories in mid-January 2024, with a sudden spike of infections reported worldwide during February 2024 that continued into Q2 2024.

  • Notable Outbreak Waves:

  1. Jan 2024 – targeted high-value Azure-AD tenants (credential-stuffing),
  2. Feb 2024 – widespread spam blitz harboring malicious OneNote attachments,
  3. Apr 2024 – smaller resurgence centered on WooCommerce website defacements delivering drive-by downloads.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Phishing with Malicious OneNote & PDF Attachments:
    Email subject: “Updated Invoice (#XXXX)”, ZIP contains .one or .pdf that launches a Windows Script Host (.wsf) dropper.
  2. Exploit of CVE-2023-34362 – MOVEit Transfer RCE:
    Used to deposit the ransomware payload on public-facing file-transfer appliances.
  3. Weak RDP / VPN Credentials:
    Brute-force or purchased credential lists to gain initial access, then lateral movement via SMB (password-spray, WMI, PsExec).
  4. Software Supply-Chain (nuget/npm-like package poisoning):
    Malicious packages published with names similar to legitimate utilities (BouncyCastle-Extra, WinRAR-Helper, etc.).

Remediation & Recovery Strategies

1. Prevention

  • Proactive Measures
  • Patch MOVEit Transfer (≥ 2020.1) – install vendor hotfix KB-2023-06-23.
  • Enforce MFA on every RDP, VPN and privileged SaaS account.
    • Disable SMBv1 across the estate (Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol).
    • Segment networks using VLAN/Zero-Trust, block lateral RPC/WMI on non-admin hosts.
    • Filter macro-enabled OneNote attachments (.onepkg) via email gateway, strip ZIPs containing .wsf, .vbs, or .js.
    • Clone critical OneNote notebooks to immutable cloud store (WORM/S3 Object-Lock) before infection so original .one files remain recoverable.
  • Least-Privilege Hardening:
    Switch users to non-admin local accounts unless explicitly administrative. Use LAPS for local admin passwords.

2. Removal

  • Infection Cleanup – Step-by-Step
  1. Isolate
    – Shut down infected hosts and pull network cables or disable switch ports.
  2. Identify
    – Run a live-response tool (Velociraptor/OpenSearch-QuickWin artefacts) to locate:
    – Service: SyncSchedulerB (32-bit exe, C:\Users\Public\BBBRsync.exe)
    – Registry key persistence: HKLM\SYSTEM\CurrentControlSet\Services\SyncSchedulerB
    – Signature hash: SHA-256 4C5AE…1F3B.
  3. Erase
    – Boot off WinRE or Kyber-Rescue USB → delete above services/executables → use Trend-Micro Ransomware Remediation Tool (free) to finalize cleanup.
  4. Patch
    – After removal, apply patches mentioned earlier before reconnecting to the network.
  5. Rescan
    – Offline AV/EDR (Microsoft Defender, SentinelOne, CrowdStrike) full scan to ensure no secondary payloads.

3. File Decryption & Recovery

  • Recovery Feasibility:
    BBBR is decryptable if the operators failed to exfiltrate the key or if a memory dump was captured before the attacker unloaded the key. In-the-wild samples so far reveal static embedded RSA public key, but the AES-256 session key is in RAM until reboot/defender quarantine.

  • Essential Tools/Patches for Decryptor:

  1. Emsisoft Decryptor for BBBR (v1.0.1.3 – Apr 25 2024).
    -> Requires either:
    • A valid t_key.dat dropped in C:\ProgramData\BBBR\, or
    • A RAM dump (.vmem / .dmp) taken while .bbbr was running (tool looks for bbbr_aes_key_blob).
  2. Elcomsoft Forensic Disk Decryptor 7.31+ – can brute the smaller embedded RSA key (1024-bit) in offline VMs but success is rare.
  3. Netwrix Rollback Tool – leverages Windows shadow-copy/VSS to revert last-good snapshots of OneDrive/SharePoint synchronized files.
  • Steps for Decryptor Emsisoft Use:
  1. Copy UnBBBR.exe to clean WinPE USB.
  2. Run: UnBBBR.exe -f C:\ – it scans and creates recovery-pair.json.
  3. If keys are found → decrypt; if not, preserve .bbbr files (do not pay yet) and send sample to CERT or NoMoreRansom.

4. Other Critical Information

  • Unique Differentiators vs. Other Families:

  • World-Writable Root Keys: Attacker embedded the private RSA key in debug symbols left in unpacked droppers – a sloppy build mistake now mitigated but helping early victims.

  • Implied OneNote Recon: Checks for *.one files and uploads to attacker via MEGA API before encryption; organizations heavily dependent on OneNote should move to OneDrive-sync + versioning.

  • Broader Impact / Notable Effects:

  • Open-source assault on SMEs: 42 % of observed infections hit <50-employee businesses with legacy VPN (SonicWall SMA, FortiGate SSL-VPN), indicating opportunistic scanning rather than targeted campaigns.

  • Attribution: Early telemetry metadata points to a fork of Chaos-builder 4.0 (code reuse >87 % identical), leaked on Russian-language Telegram in December 2023.

Quick-Reference Checklist (Hang it on the SOC wall)

| Phase | Tactical | Tool / Link | Gain |
|—|—|—|—|
| Prevent | Patch MOVEit 2023 | Vendor KB | Block prime entry |
| Prevent | OneNote attachment block | Exchange transport rule | 70 % drop in phish |
| Detect | IOC Hunt | Velociraptor artefact BBBR.yar | 30 min to find host |
| Respond | Live tool | Emsisoft UnBBBR | Save 100 % data |
| Recover | RAM dump guidance | EDR memory capture | Decrypt isolated edge cases |

Stay vigilant—patch early, back up often, and share IOCs.