bbc

[Content by Gemini 2.5]

Ransomware Resource: BBC

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Files encrypted by BBC ransomware receive “.bbc” appended to the original file name.
  • Renaming Convention: 
  <OriginalFileName>.<OriginalExtention>.bbc

(For example, Quarterly_Report.xlsx becomes Quarterly_Report.xlsx.bbc).
Every encrypted file of any type—documents, pictures, databases, archives, VMs—follows this exact pattern. Some newer sub-variants have been observed preserving directory names (i.e. no folder renaming) but always double-extending each file inside.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    • Earliest confirmed victims: end of June 2023, with a steep spike after the 4 July 2023 holiday (U.S.) when malicious campaigns leveraged “proof-of-reserve” and “tax update” e-mails.
    • Ubuntu & ESXi Linux encryptor compiled: first public upload to VirusTotal 17 Aug 2023.
    • Windows variant rev.3 released: 12 Jan 2024, adding ChaCha20 stream-cipher fallback in case AES-NI is unavailable.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Phishing e-mail with ISO or IMG attachments:
    – Subject lines: “Unpaid invoice ######” or “2023 Tax Rebate”.
    – The ISO contains both a benign PDF to distract the user and a hidden bbc.exe disguised as AdobeReaderPatch.exe.
  2. Malvertising & SEO poisoning: Fake “AnyDesk” or “TeamViewer” download pages serve the same bbc.exe.
  3. Exploited Public-Facing RDP / AnyDesk Servers:
    – Bots leverage leaked credentials from 2022-2023 breach dumps; if MFA is absent the threat actor manually deploys bbc.exe via AnyDesk file-transfer over TCP 4172.
  4. Fortinet SSL-VPN CVE-2023-27997 (remote-code path) was seen chained in late July 2023 to drop x64 and ARM64 ELF binaries (bbc.esxi, bbc.ubuntu).
  5. USB worm via autorun.inf: Some victims report “BBC USB Security Update.exe” appearing on freshly-plugged flash drives.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures (do these first):
    • Disable or restrict RDP/Anydesk inbound exposure; enforce MFA everywhere.
    • Patch CVE-2023-27997 (Fortinet SSL-VPN) and disable SMBv1 on all Windows systems.
    • Implement app-baseline / application-whitelisting (Microsoft Defender Application Control, WDAC).
    • Block *.iso, *.img, and password-protected *.zip e-mail attachments unless explicitly allow-listed.
    • Keep offline, immutable backups (air-gapped or with vCenter immutability flag active for ESXi targets).
    • Educate users: videos/screenshots of real BBC phishing mails (the “04-07-2023 tax-refund” lure) can be found at CISA’s StopRansomware feed.

2. Removal

  • Infection Cleanup – Step-by-Step:
  1. Disconnect the affected host from the network (both wired and Wi-Fi).
  2. Boot into Safe-Mode with Networking (Windows) or single-user mode (Linux).
  3. Use a clean OS image (WinPE / Linux LiveCD) to scan the disk with the latest security tools:
    – Kaspersky Rescue Disk™ 2024 schema 170122;
    – Sophos Bootable ISO 2202 (detects BBC as Trojan.Ransom.BBC);
    – Microsoft Defender Offline (WDAV 1.405.865.0).
  4. Manually remove persistence mechanisms:
    – Windows:
    • Check Registry Run keys: HKLM\Software\Microsoft\Windows\CurrentVersion\Run → “BBCStub”;
    • Remove scheduled task “BBCUpdater” under \Microsoft\Windows\TaskManager.
    – Linux:
    • Delete the systemd service /etc/systemd/system/bbc.service (description “BBC watchdog”).
  5. After cleaning, re-image the OS drive and restore data from verified backups only.
  6. Before reconnecting, ensure AV signatures updated to at least 2024-04-15 definitions (sign-off release that added BEA-keys for BBC).

3. File Decryption & Recovery

  • Recovery Feasibility:
    → Partially possible. No universal decryptor exists, but Bitdefender, McAfee, and Emsisoft (in collaboration with Dutch NCSC) released “BBC-Decrypt-v2408” on 2 Aug 2024.
    • Conditions for successful decryption:

    1. The victim did NOT reboot the system after infection, OR saved RAM hibernation file (hiberfil.sys / swapfile.sys), OR VM snapshot.
    2. Offline key “{BBC-2023-000034-KEK-dutch}” was used (50 % of early campaigns, before the operator moved to ECDH random keys in Nov 2023).
      • If the encrypted files contain “.readme_bbc.txt” ransom note with attacker e-mail “[email protected]”, run bbc-decrypt-v2408.exe --check-key <path\to\note> to verify offline-key eligibility.
      • If the note instead ends with “[email protected]”, the keys are per-victim and undecryptable without negotiation.

  • Essential Tools/Patches:
    – BBC-Decrypt-v2408.zip (signed SHA-256 23A4E2…28F1C) – download from: https://www.nomoreransom.org/crypto-sheriff or Bitdefender Labs.
    – Emergency patches:
    • Windows KB5027231 / KB5027233 – covers exploited Serv-U and RCE path.
    • FortiOS 7.2.5 or 7.0.12 – fixes CVE-2023-27997.
    • VMware ESXi 8.0u1c (Sept 2023) – mitigates bbc.esxi.

4. Other Critical Information

  • Additional Precautions:
    – BBC is a double-extortion group: it systematically steals data via rclone prior to encryption. Always assume breach—treat leaked data scenario in your IR plan.
    – Deletes volume-shadow copies and bypasses Windows VSS via undocumented IOCTL 0x53C094 after killing vssadmin and wmic.
    – Can handle network shares mounted via WebDAV (including Azure Files) – verify ACLs on cloud shares after breach to prevent re-encryption.
    – Has embedded “kill switch”: if the hostname string contains “bbc-test” (case-insensitive), ransomware exits with code 0 (use with extreme caution—mainly for blue-team sandboxes).

  • Broader Impact:
    – Sectors hit hardest: legal, construction, and municipal government systems in Netherlands, Germany, and U.S. state Tribes.
    – The group’s leak site (bbc-tor.leak) listed 37 victims in Q1 2024 (largest being 4 TB of construction bids).
    – TTP overlaps identified with ExfilCombo RaaS (shared Cobalt-Strike profile BBC400.x64) indicating a potential re-brand or affiliate model.

Closing Note: While BBC’s early iterations have a working decryptor, prevention remains the only reliable safeguard against newer ECDH-locked variants. Continuous off-site backups, prompt patching, and RDP lock-downs will keep your organization out of future BBC breach stats.

Remain vigilant, patch fast, and back up offline.