Sigma rule: Process Creation Using Sysnative Folder

Rule

Title

Process Creation Using Sysnative Folder

Status

test

Level

medium

Author

Max Altgelt (Nextron Systems)

Date

2022-08-23

Modified

2025-10-08

File

rules/windows/process_creation/proc_creation_win_susp_sysnative.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects process creation events that use the Sysnative folder (common for CobaltStrike spawns)

Log source

product

windows

category

process_creation

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_*

False positives (as the rule lists them)

• Unknown

Tags

• attack.privilege-escalation
• attack.stealth
• attack.t1055

MITRE ATT&CK ids this rule names

• T1055

References

• https://thedfirreport.com/2021/08/29/cobalt-strike-a-defenders-guide/

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_susp_sysnative.yml