Detects .NET red/black-team tools via name

Hunt Hypothesis

This detection identifies the execution of known .NET-based Red and Blue team utility names to distinguish legitimate security operations from potential adversary tooling that mimics these signatures. Proactive hunting for this behavior in Azure Sentinel is essential to validate authorized activities and uncover stealthy threat actors leveraging familiar .NET tools to evade initial detection mechanisms.

YARA Rule

rule HKTL_NET_NAME_SharpWatchdogs {
    meta:
        description = "Detects .NET red/black-team tools via name"
        reference = "https://github.com/RITRedteam/SharpWatchdogs"
        author = "Arnim Rupp"
        date = "2021-01-22"
    strings:
        $name = "SharpWatchdogs" ascii wide
        $compile = "AssemblyTitle" ascii wide
    condition:
        (uint16(0) == 0x5A4D and uint32(uint32(0x3C)) == 0x00004550) and all 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/RITRedteam/SharpWatchdogs
• Source Rule

False Positive Guidance

Here are 5 specific false positive scenarios for the rule “Detects .NET red/blue-team tools via name”, including suggested filters and exclusions:

• Scenario: Automated Compliance Scanning by Admin

  • Context: The internal compliance team runs a scheduled nightly job using Microsoft Defender for Identity or Qualys Cloud Agent (built on .NET) to scan endpoint configurations. These agents often execute binaries with names like ComplianceScan.exe or AgentService.exe, which match the rule’s signature for red/blue team tools.
  • Filter/Exclusion: Exclude processes where the parent process is a known service host (svchost.exe) or a specific scheduled task ID (e.g., \Microsoft\Windows\Defender Identity\ComplianceScan). Alternatively, filter based on the ImageFileName containing “Qualys” or “Defender”.

• Scenario: Development Environment Deployment

  • Context: The DevOps team utilizes Octopus Deploy or Azure DevOps Agents to deploy .NET applications. During deployment, these agents execute tooling binaries such as Octo.exe or VstsTaskAgent.exe, which are often categorized under the same naming convention as security testing tools in the rule logic.
  • Filter/Exclusion: Create an exclusion list for specific hostnames belonging to the CI/CD infrastructure (e.g., *-build-server-01, *-deploy-agent). Additionally, filter out events where the process path contains \Program Files\Octopus Deploy\ or \Azure DevOps Agent\.

• Scenario: Internal Patch Management Execution

  • Context: The IT Operations team uses PDQ Inventory (a .NET-based tool) to push patches and inventory updates. When PDQ runs its agent or installer, it launches PdqAgent.exe or `Pd