PowerShell Core DLL Loaded Via Office Application

SIGMA detection rule by Nasreddine Bencherchali (Nextron Systems) · NOASSERTION

Detects PowerShell core DLL being loaded by an Office Product

title: PowerShell Core DLL Loaded Via Office Application
id: bb2ba6fb-95d4-4a25-89fc-30bb736c021a
status: test
description: Detects PowerShell core DLL being loaded by an Office Product
references:
    - Internal Research
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-06-01
tags:
    - attack.stealth
logsource:
    category: image_load
    product: windows
detection:
    selection:
        Image|endswith:
            - '\excel.exe'
            - '\mspub.exe'
            - '\outlook.exe'
            - '\onenote.exe'
            - '\onenoteim.exe' # Just in case
            - '\powerpnt.exe'
            - '\winword.exe'
        ImageLoaded|contains:
            - '\System.Management.Automation.Dll'
            - '\System.Management.Automation.ni.Dll'
    condition: selection
falsepositives:
    - Unknown
level: medium

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

f9b51ba7-60ac-4364-9301-8b695a348026

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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

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

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

[[ currentRule.title ]]

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