Suspicious Process Creation Via Sysnative Folder (via process_creation)

title: Suspicious Process Creation Via Sysnative Folder (via process_creation)
id: 7ad67724-6ac8-51ab-a724-8b77faf282e1
status: stable
description: This rule detects process creation events that use the Sysnative folder (common for CobaltStrike spawns)
references:
    - https://attack.mitre.org/techniques/T1055/
    - https://thedfirreport.com/2021/08/29/cobalt-strike-a-defenders-guide/
author: Huntrule Team
date: 2026-01-21
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1055
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        - CommandLine|contains: ':\Windows\Sysnative\'
        - Image|contains: ':\Windows\Sysnative\'
    filter_main_ngen:
        Image|contains:
            - 'C:\Windows\Microsoft.NET\Framework64\v'
            - 'C:\Windows\Microsoft.NET\Framework\v'
            - 'C:\Windows\Microsoft.NET\FrameworkArm\v'
            - 'C:\Windows\Microsoft.NET\FrameworkArm64\v'
        Image|endswith: '\ngen.exe'
        CommandLine|contains: 'install'
    filter_optional_xampp:
        CommandLine|contains|all:
            - '"C:\Windows\sysnative\cmd.exe"'
            - '\xampp\'
            - '\catalina_start.bat'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: medium