Suspicious Powershell Cmdlets

SIGMA detection rule by Micah Babinski · GPL-3.0

Looks for look for cmdlets, methods, and switches that may indicate malicious activity. Inspired by the 2022 Red Canary Threat Detection report.

title: Suspicious Powershell Cmdlets
id: b3dfac86-1056-4b6b-9c67-db4a10a9e812
status: experimental
description: Looks for look for cmdlets, methods, and switches that may indicate malicious
    activity. Inspired by the 2022 Red Canary Threat Detection report.
references:
    - https://redcanary.com/threat-detection-report/techniques/powershell/
author: Micah Babinski
date: 2022/11/03
tags:
    - attack.execution
    - attack.t1059
    - attack.t1059.001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\powershell.exe'
        CommandLine|contains|windash:
            - '-nop'
            - '-noni'
            - 'invoke-expression'
            - 'iex'
            - 'downloadstring'
            - 'downloadfile'
            - 'downloadata'
    condition: selection
falsepositives:
    - Unknown
level: high

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

68851b82-442c-4061-a73c-1f941eb574b0

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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

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.

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What do these messages mean?

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

[[ currentRule.title ]]

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