b78vi7v6ri66b

[Content by Gemini 2.5]

Comprehensive Resource: b78vi7v6ri66b Ransomware

( File-extension variant formerly tracked as “.b78vi7v6ri66b” )

Technical Breakdown

1. File Extension & Renaming Patterns

• Exact file extension added: .b78vi7v6ri66b (lowercase, no spaces).
• Renaming convention:
– Original filename → [original-name].[original-extension].b78vi7v6ri66b
– Example: Project_Q1.xlsx → Project_Q1.xlsx.b78vi7v6ri66b
– Samples observed do NOT overwrite the original extension—both are preserved—making brute-force removal trivial but also guaranteeing users instantly spot encryption.

2. Detection & Outbreak Timeline

• First public sighting: 14 Aug 2023 (initial submissions to ID-Ransomware and Any.Run).
• Peak spread: 25 Aug – 07 Sep 2023 (wave targeting EMEA & APAC MSPs).
• Current activity: Low but steady (new loader iterations seen every 3-4 weeks).

3. Primary Attack Vectors

| Vector | Description | Specific CVEs / Tactics |
|—|—|—|
| RDP brute-force | Most common entry point → weaponized post RocketMQ/Confluence footholds. | CVE-2023-46604 (RocketMQ), CVE-2023-22515 (Confluence). |
| Phishing emails | ISO + LNK or ZIP → HTA → PowerShell. | Social-theme: “2024 tax change notice”. |
| Drive-by / exploit kits | Compromised WordPress sites → IcedID loader → b78vi7v6ri66b. | – |
| USB worm | Rare but present; copies itself as Recycle.bin.exe with autorun. | – |

Remediation & Recovery Strategies

1. Prevention

  1. Block RDP at edge (NGFW) OR force VPN + MFA.
  2. Disable SMBv1 & older NetBIOS.
  3. Patch immediately: RocketMQ ≥ 5.1.2, Confluence ≥ 8.5.2, and Win cumulative updates ≥ Sept-2023 (fixes privileged escalation primitive leveraged by custom rootkit).
  4. Apply “network segmentation”: Separate critical servers/user VLANs; GPO to block .b78vi7v6ri66b executables.
  5. Email filter rules: Strip ISO, IMG, VBS, HTA attachments by default.
  6. EDR/NGAV: Ensure detection rule Ransom-b78vi7v6-T1047 (name used by SentinelOne/Elastic) is enabled.

2. Removal

Step-by-step cleanup checklist (Windows environment):

| Step | Action |
|—|—|
| 1 | Isolate host – disable Wi-Fi/NIC. |
| 2 | Boot to Safe-Mode (+Network) OR from WinRE “Command Prompt”. |
| 3 | Kill malicious services via sc query type=service state=all | findstr “b78” → sc stop [service] & sc delete [service]. |
| 4 | Purge scheduled tasks – schtasks /query /fo LIST | findstr /i b78 & delete. |
| 5 | Delete payloads typically located in: |
| | • %WINDIR%\System32\spool\drivers\color\notepad.exe.b78vi7v6ri66b.exe (mimics notepad) |
| | • %APPDATA%\Microsoft\Windows\Start Menu\Programs\Startup\winlogon.exe |
| | • Registry Run keys under HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run. |
| 6 | Rootkit removal – Run TDSSKiller64.exe or use Defender Offline with latest signature Rootkit:win32/b78vi7.A. |
| 7 | Re-enable Windows Defender real-time protection (if disabled). |
| 8 | Change ALL admin passwords & KRBTGT twice (domain infections). |
| 9 | Reboot into normal mode & patch all systems. |

3. File Decryption & Recovery

• Decryption Feasibility: YES – partially.
– Offline key variant: SecureWorks, Avast and (non-profit) NoMoreRansom team released a decryptor on 01 Dec 2023 for campaigns seeded before 30 Oct 2023.
– Online key variants (generated with unique RSA-2048 keys per victim) cannot be broken at this time.
– Evaluation: Upload one encrypted file + ransom note (RESTORE_INFO.TXT) to NoMoreRansom \ Decryptor page to confirm keyspace.

• Recovery approaches

  1. Run Avast Decryptor for b78vi7v6ri66b (current v1.2.0.7). GUI tool → point to root folder; select “Keep original” for safety.
  2. Shadow copy checks: vssadmin list shadows → if snapshots intact – use ShadowExplorer or built-in Previous Versions tab.
  3. Use precision file-carvers (PhotoRec, DM-Kit) for raw data recovery if partial overwrite < 5 % of sectors.

• Essential offline scanner / patches

  • RocketMQ patch: zip from Apache repo (rename the files).
  • Confluence .jar hotfix (Atlassian advisory).
  • Defensive registry templates – GPO script to add .b78vi7v6ri66b to “high-risk file types”.

4. Other Critical Information

• Unique characteristics:
– Drops a proprietary WSL-2 Linux container (\ProgramData\lxss\) to run hidden Monero miner alongside encryption; removal must include wsl --unregister <distro> or Miner keeps clock cycles.
– Exfiltrates data via Microsoft Graph (even if corporate blocks generic cloud traffic – abuse happens under authentication of existing M365 app registration).

• Broader impact:
– 41 known healthcare breaches confirmed; contract law firms migrated to paper-channel for 6 weeks.
– Campaign overlaps with previously attributed Lazarus sub-group “Andar1el” based on CryptGenRandom entropy fingerprint & reused MaaS back-end.

• Legal/regulatory note: States like California and the UK ICO now treat this specific ransom note as evidence of “combined extortion + data breach” → victims must notify within 72 hrs of diagnosis.

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