Rundll32 with Suspicious Process Lineage

SIGMA detection rule by RedCanary, Sigma formatting by Micah Babinski · GPL-3.0

As is the case with most techniques in this report, it's critical that you are able to take stock of what is normal in your environment if you hope to be able to identify what isn't. In the context of Rundll32, you’ll want to monitor for executions of rundll32.exe from unusual parent processes, and the following pseudo-analytic—based on an amalgamation of Red Canary detection logic—should help security teams do just that. Part of the RedCanary 2024 Threat Detection Report.

title: Rundll32 with Suspicious Process Lineage
id: 5025ecc7-1efd-41de-aee2-38f4b9d8d281
status: experimental
description: |
    As is the case with most techniques in this report, it's critical that 
    you are able to take stock of what is normal in your environment if you 
    hope to be able to identify what isn't. In the context of Rundll32, you’ll 
    want to monitor for executions of rundll32.exe from unusual parent processes, 
    and the following pseudo-analytic—based on an amalgamation of Red Canary 
    detection logic—should help security teams do just that. Part of the RedCanary 
    2024 Threat Detection Report.
references:
    - https://redcanary.com/threat-detection-report/techniques/rundll32/
author: RedCanary, Sigma formatting by Micah Babinski
date: 2024/03/21
tags:
    - attack.defense_evasion
    - attack.t1218
    - attack.t1218.011
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith:
            - '\winword.exe'
            - '\excel.exe'
            - '\msaccess.exe'
            - '\lsass.exe'
            - '\taskeng.exe'
            - '\winlogon.exe'
            - '\schtasks.exe'
            - '\regsvr32.exe'
            - '\wmiprvse.exe'
            - '\wsmprovhost.exe'
        Image|endswith: '\rundll32.exe'
    condition: selection
falsepositives:
    - Unknown
level: low

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794ffb98-2993-43cb-89a9-c632e399f171

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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.

Rejected pattern present

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Format & documentation suggestions

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