Windows Processes Suspicious Parent Directory

SIGMA detection rule by vburov · NOASSERTION

Detect suspicious parent processes of well-known Windows processes

title: Windows Processes Suspicious Parent Directory
id: 96036718-71cc-4027-a538-d1587e0006a7
status: test
description: Detect suspicious parent processes of well-known Windows processes
references:
    - https://web.archive.org/web/20180718061628/https://securitybytes.io/blue-team-fundamentals-part-two-windows-processes-759fe15965e2
    - https://www.carbonblack.com/2014/06/10/screenshot-demo-hunt-evil-faster-than-ever-with-carbon-black/
    - https://www.13cubed.com/downloads/windows_process_genealogy_v2.pdf
author: vburov
date: 2019-02-23
modified: 2025-03-06
tags:
    - attack.stealth
    - attack.t1036.003
    - attack.t1036.005
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\svchost.exe'
            - '\taskhost.exe'
            - '\lsm.exe'
            - '\lsass.exe'
            - '\services.exe'
            - '\lsaiso.exe'
            - '\csrss.exe'
            - '\wininit.exe'
            - '\winlogon.exe'
    filter_sys:
        - ParentImage|endswith:
              - '\SavService.exe'
              - '\ngen.exe'
        - ParentImage|contains:
              - '\System32\'
              - '\SysWOW64\'
    filter_msmpeng:
        ParentImage|contains:
            - '\Windows Defender\'
            - '\Microsoft Security Client\'
        ParentImage|endswith: '\MsMpEng.exe'
    filter_null:
        - ParentImage: null
        - ParentImage:
              - ''
              - '-'
    condition: selection and not 1 of filter_*
falsepositives:
    - Some security products seem to spawn these
level: low

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Executable code, not a declarative rule

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