Detects c# red/black-team tools via typelibguid

Hunt Hypothesis

This detection identifies the execution of specialized C# Red and Black team tools by analyzing unique TypeLibGUID signatures within Azure Sentinel logs. Proactive hunting for these indicators is essential to distinguish legitimate security testing activities from potential adversary use of similar custom frameworks that could mask malicious operations.

YARA Rule

rule HKTL_NET_GUID_TeleShadow2 {
    meta:
        description = "Detects c# red/black-team tools via typelibguid"
        reference = "https://github.com/ParsingTeam/TeleShadow2"
        author = "Arnim Rupp"
        date = "2020-12-28"
    strings:
        $typelibguid0 = "42c5c356-39cf-4c07-96df-ebb0ccf78ca4" ascii nocase wide
        $typelibguid1 = "0242b5b1-4d26-413e-8c8c-13b4ed30d510" ascii nocase wide
    condition:
        (uint16(0) == 0x5A4D and uint32(uint32(0x3C)) == 0x00004550) and any of them
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

• Microsoft Defender for Endpoint — Custom indicators / advanced hunting
• Email Gateway — Attachment scanning
• File Share Monitoring — Periodic scanning of shared drives
• YARA CLI — Manual threat hunting on endpoints

This rule contains 2 string patterns in its detection logic.

References

• https://github.com/ParsingTeam/TeleShadow2
• Source Rule

False Positive Guidance

Here are specific false positive scenarios for the rule “Detects c# red/black-team tools via typelibguid”, including suggested filters and exclusions:

• Scenario: Automated Deployment Pipelines

  • Context: CI/CD agents (e.g., Azure DevOps, Jenkins) executing C# build tasks or running PowerShell scripts that utilize .NET assemblies with standard TypeLibGuids during nightly builds. These often mimic the behavior of Red Team tools by loading specific COM objects.
  • Filter/Exclusion: Exclude processes matching known CI/CD service accounts (e.g., NT SERVICE\TeamFoundationBuild, Jenkins) and restrict detection to non-build server workstations. Alternatively, add a filter for process paths containing \AzureDevOps\ or \Jenkins\.

• Scenario: Endpoint Protection Scanning

  • Context: Enterprise EDR agents (e.g., CrowdStrike Falcon, Microsoft Defender) performing real-time scanning or heuristic analysis on .NET applications. The scanner may instantiate C# tools to analyze file integrity, triggering the TypeLibGuid signature associated with security tooling.
  • Filter/Exclusion: Create an exclusion for processes belonging to major EDR vendors (e.g., C:\Program Files\CrowdStrike\, C:\ProgramData\Microsoft\Windows Defender\). Filter out events where the parent process is the EDR service itself.

• Scenario: Scheduled Office 365/SharePoint Provisioning Jobs

  • Context: Automated administrative tasks running via Task Scheduler that utilize C# scripts to manage SharePoint sites or O365 user provisioning. These jobs often load specific TypeLibGuids related to Microsoft Graph or Exchange Web Services, which overlap with Red Team tool signatures.
  • Filter/Exclusion: Exclude events occurring during defined maintenance windows (e.g., 02: