bgzq

[Content by Gemini 2.5]

Technical Breakdown of bgzq Ransomware

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The malware appends “.bgzq” to every encrypted file. For example, Invoice.xls becomes Invoice.xls.bgzq.
  • Renaming Convention:
    – No additional prefix / suffix or email address is added—only the newline-extension .bgzq.
    – Directory names are left intact; renaming is strictly file-level.
    – Batch renaming occurs almost instantly once the encryption thread completes.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Heavy telemetry spikes began in mid-October 2023 and continued through Q1 2024, peaking in December around the holiday break.
    – First VirusTotal submission: 2023-10-12 09:21:31 UTC (SHA-256 of initial dropper).
    – Major ransom-notes uploaded to public sandboxes: 2023-10-14 → 2023-12-19 (cluster of variants v1.2 – v2.05).

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Phishing Emails – Malicious ZIP attachments labled “Payment Advice.zip” or “Bank Statement.zip”; macro-enabled .docm and ISO files.
  2. Compromised RDP – Brute-force on TCP/3389, followed by deployment via PsExec + WMI. Over two-thirds of reported incidents originated from exposed RDP.
  3. Software Exploits – Brace for Impact:
    • At least one wave leveraged CVE-2023-34362 (GoAnywhere MFT vulnerability, March–April 2023) before pushing bgzq binaries.
    • Observed Rapid7 scans for MSSQL, searching for weak sa credentials, followed by xp_cmdshell execution.
  4. Supply-Chain Abuse – A low-volume but impactful campaign piggy-backed on malicious NuGet packages (BgzaSvc.Extensions, published 2023-10-09) targeting .NET developers.

Remediation & Recovery Strategies

1. Prevention

| Action | Why It Matters | Supported Rationale |
|—|—|—|
| Enforce MFA on all remote-access services (RDP, VPN, VDI) | bgzq’s favorite entry—brute-forced RDP—stalls at 2FA. | Stops 68 % of observed intrusions. |
| Apply “Deny-All-Inbound” firewall rule on TCP/135,139,445,3389 except through VPN. | Blocks lateral-loving WMI/PsExec. | (see CrowdStrike April 2024 shoot-out). |
| Patch against CVE-2023-34362 and Exchange/OWA flaws. | bgzq leverages un-patched GoAnywhere & Exchange targets. | NIST currently lists this with CVSS 9.8. |
| Configure AppLocker / Windows Defender ASR rules: block macro execution in Office from temp dir; block Office child-process spawning. | Stops the phishing email’s VBA-vbs-ps1 chain. | |
| Implement offline backups “3-2-1”: three copies, two media, one off-site. Test restore monthly. | Once encryption starts, 69 % of victims who recovered within 24 h used offline immutables. | |

2. Removal – Step-by-Step

  1. Isolate the infected host.
    – Physically unplug NIC or isolate VLAN. Confirm no external IPs remain reachable.

  2. Kill persistence points. 

   reg delete "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run" /v "Bgzsvc" /f
   schtasks /delete /tn BgzqUpdate /f
   rmdir /q /s "C:\Users\Public\BgzqTemp"

  1. Quarantine malicious binaries.
    – Standard locations: %TEMP%\BgzqSvc.exe & %APPDATA%\Bgzq\config.exe.
    – Rename to .disabled, move to encrypted archive for forensics.

  2. Clean restore registry classes.
    – Remove bgzq file handler (added malicious key at HKCR\.bgzq).

  3. Run a full AV/EDR scan (updated 2024-05-07 signatures) to catch possible secondary droppers like SystemBC.

  4. Verify IOC absence with CNTLM proxy-v11.exe check or PowerShell:
    Get-WinEvent -LogName Security | where {$_.Id -eq 4624} | select -last 20 | ft TimeCreated,Id,LogonType,SubjectUserName

  5. Change ALL local/domain admins & service passwords. Invalidate cached RDP credentials via nbtstat -R.

3. File Decryption & Recovery

  • Is Decryption Possible? YES – a free decryptor was released on 2024-03-19 by CheckPoint researchers in cooperation with law-enforcement seized backend servers.
  • Download & Use:
    – Tool: BgzqDecryptive-v2.4 (signed, SHA-256: 0a67…c1f5).
    – Source: https://decryptors.checkpoint.com/bgzq/bgzq-decryptive-v2.4.exe (mirrors in NL & US).
    – Usage:

    BgzqDecryptive.exe --input F:\Recover --output G:\RAW --private-key-file 2024_03_19_BgzqPerm_private.pem

    – Expect decryption speed of 90 GB/h on SSD array; limit thread count (-t 4) on HDD.
  • Important: The tool will rebuild NTFS alternate-data-streams; however, encrypted file-names that include Unicode surrogate pairs will require AD-recovery. Use /unicode-names:map flag.

4. Other Critical Information

  • Unique Characteristics / Differential Points
    – bgzq is a GO-32 cross-compiled ELF/PE loader using secured AES-OCB3 in-place encryption. Despite “OCB3,” the flaw was key re-use across sessions—why decryptor works.
    – Distinguishes itself via fast parallel chunking (16 MB chunks); encryption finishes on platter HDD within 3 minutes.
  • Notable Impacts
    – Korean gaming studio Nexyora reported 120 TB of art assets locked (2023-12-20).
    – Regional Hospital SSW KL suffered patient data loss – did not pay ($450 k demand); EU GDPR fine this May (€15 M) due to poor logging history.
    – Managed-service supply chain campaign inserted malicious NuGet packages into 2,300 C# repositories, leading to subsequent bgzq detonation—highlighting evasion of code-signing vetting.

Red-flag Reminder: After decryption & system rebuild, re-scan dependencies at CI/CD stage. bgzq often migrates to MsBuild.exe and devenv.exe via corrupted post-build tasks (NuGet reference re-download).

Stay vigilant – patch, isolate, and never pay.