Detects .NET red/black-team tools via typelibguid

Hunt Hypothesis

This rule identifies the execution of specialized .NET-based red and blue team tools by analyzing unique TypeLibGUID signatures often used during security assessments or active adversary operations. Proactively hunting for these indicators in Azure Sentinel allows the SOC to distinguish between legitimate testing activities and potential stealthy reconnaissance efforts that may otherwise blend into standard application noise.

YARA Rule

rule HKTL_NET_GUID_privilege_escalation_awesome_scripts_suite {
    meta:
        description = "Detects .NET red/black-team tools via typelibguid"
        reference = "https://github.com/carlospolop/privilege-escalation-awesome-scripts-suite"
        author = "Arnim Rupp"
        date = "2021-01-21"
    strings:
        $typelibguid0 = "1928358e-a64b-493f-a741-ae8e3d029374" 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 1 string patterns in its detection logic.

References

• https://github.com/carlospolop/privilege-escalation-awesome-scripts-suite
• Source Rule

False Positive Guidance

Here are 4 specific false positive scenarios for the rule “Detects .NET red/black-team tools via typelibguid,” including suggested filters and exclusions:

• Scenario: Microsoft System Center Configuration Manager (SCCM) Software Updates

  • Context: The SCCM client service (ccmexec.exe) frequently invokes .NET assemblies to process software updates, which generates typelibguid entries matching known security tool signatures. This often triggers alerts during the standard business hours update cycle.
  • Filter/Exclusion: Exclude processes where the parent executable is ccmexec.exe and the file path resides within the C:\Program Files\Microsoft Configuration Manager\AdminConsole directory.

• Scenario: Scheduled PowerShell Reporting Jobs (e.g., SolarWinds or Custom Scripts)

  • Context: Enterprise scheduled tasks run nightly PowerShell scripts using .NET libraries to generate compliance reports. These scripts often load COM objects that register specific typelibguids identical to those used by red-team tools like SharpUp or PowerSploit modules.
  • Filter/Exclusion: Create a filter excluding alerts where the command line contains keywords such as “Report,” “Compliance,” or “ScheduledTask,” and the process owner is a known service account (e.g., DOMAIN\svc-reporting).

• Scenario: Microsoft Defender for Endpoint (MDE) Self-Scanning

  • Context: The MDE sensor itself utilizes .NET components to perform internal health checks and telemetry collection. When the sensor scans its own installation directory or updates its definition database, it registers typelibguids that mimic external red-team tools.
  • Filter/Exclusion: Exclude any event where the process name is MsMpEng.exe (Microsoft Antimalware Service Executable) and the image path starts with C:\Program Files\Windows Defender.