cve-2025-49666 detection rule

[17patmaks]

Summary of the Pull Request

This PR adds a new Sigma detection rule for CVE-2025-49666, a critical heap-based buffer overflow vulnerability in the Windows Setup and Boot Event Collection (SBEC) service. The vulnerability allows authenticated attackers to achieve remote code execution with SYSTEM-level privileges.

The rule detects exploitation attempts by monitoring for:

• Suspicious child processes (cmd.exe, powershell.exe, script interpreters) spawned by svchost.exe with references to the SBEC service
• Windows Error Reporting crash indicators related to SBEC service exploitation

This detection focuses on process creation events and can identify both successful exploitation (malicious process spawning) and failed attempts (service crashes).

Changelog

new: CVE-2025-49666 Windows SBEC Service Exploitation Detection

Example Log Event

Successful Exploitation - Suspicious Child Process:

EventID: 4688 (Process Creation)
ParentImage: C:\Windows\System32\svchost.exe
Image: C:\Windows\System32\cmd.exe
CommandLine: cmd.exe /c whoami sbsvc

Failed Exploitation - Crash Indicator:

EventID: 4688 (Process Creation)
Image: C:\Windows\System32\WerFault.exe
CommandLine: C:\Windows\system32\WerFault.exe -u -p 1234 -s 567 sbsvc.dll

Fixed Issues

N/A - This is a new rule, not fixing existing issues.

SigmaHQ Rule Creation Conventions

• If your PR adds new rules, please consider following and applying these conventions

• Followed naming conventions (cve_2025_49666_detection.yml)

• Included required fields (title, id, status, description, author, date, logsource, detection, level)

• Used appropriate MITRE ATT&CK tags (T1190, T1203)

• Documented false positives

• Added relevant references to official sources

• Rule tested and validated locally

[swachchhanda000]

Hi @17patmaks,

Thanks for the submission. However, before we proceed with review, could you please share any reference on cve-2025-49666, such as how is it exploited, poc code or detection opportunity or EVTX logs? This will help us better understand how you arrived at this detection logic. I wasn’t able to find much information from the references used in the rule or in the description.

[17patmaks]

CVE-2025-49666 has limited public information.

Additional References

• NVD: https://nvd.nist.gov/vuln/detail/CVE-2025
• Zero Day Initiative: https://www.zerodayinitiative.com/blog/2025/7/8/the-july-2025-security-update-review (Listed as "Windows Server Setup and Boot Event Collection RCE"

Since no POC or EVTX logs exist for CVE-2025-49666, I modeled this detection after CVE-2024-38063 which does have similar characteristics:

• Both are Windows kernel-level RCE vulnerabilities
• Both allow authenticated remote code execution
• Both result in SYSTEM-level privileges

Post-exploitation pattern: After successful RCE in Windows services, attackers consistently spawn shells (cmd.exe, powershell.exe) or script interpreters (wscript/cscript) from svchost.exe to establish initial access and download additional payloads. This pattern is documented across CVE-2024-38063 and similar Windows service RCE vulnerabilities.

Splunk's Windows Service Spawned Shell detection uses the same process pattern: https://research.splunk.com/endpoint/d8120352-3b62-4e3c-8cb6-7b47584dd5e8/

The CommandLine|contains: 'sbsvc' filter reduces false positives by focusing specifically on SBEC-related activity.

This is an inferential detection based on exploitation patterns rather than observed CVE-2025-49666 attacks.

[17patmaks]

Hi @swachchhanda000

Thank you for the feedback, I hope the explanation I provided helps with understanding the methodology behind this detection. I have also fixed the indentation errors were present.