Suspicious Process Parents

SIGMA detection rule by Florian Roth (Nextron Systems) · NOASSERTION

Detects suspicious parent processes that should not have any children or should only have a single possible child program

title: Suspicious Process Parents
id: cbec226f-63d9-4eca-9f52-dfb6652f24df
status: test
description: Detects suspicious parent processes that should not have any children or should only have a single possible child program
references:
    - https://twitter.com/x86matthew/status/1505476263464607744?s=12
    - https://svch0st.medium.com/stats-from-hunting-cobalt-strike-beacons-c17e56255f9b
author: Florian Roth (Nextron Systems)
date: 2022-03-21
modified: 2022-09-08
tags:
    - attack.stealth
    - attack.t1036
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith:
            - '\minesweeper.exe'
            - '\winver.exe'
            - '\bitsadmin.exe'
    selection_special:
        ParentImage|endswith:
            - '\csrss.exe'
            - '\certutil.exe'
         # - '\schtasks.exe'
            - '\eventvwr.exe'
            - '\calc.exe'
            - '\notepad.exe'
    filter_special:
        Image|endswith:
            - '\WerFault.exe'
            - '\wermgr.exe'
            - '\conhost.exe' # csrss.exe, certutil.exe
            - '\mmc.exe'     # eventvwr.exe
            - '\win32calc.exe' # calc.exe
            - '\notepad.exe'
    filter_null:
        Image: null
    condition: selection or ( selection_special and not 1 of filter_* )
falsepositives:
    - Unknown
level: high

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

b9684b63-80cd-4828-b65d-3b7fe1261345

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

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Format & documentation suggestions

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