Potential Persistence Via PowerShell User Profile Using Add-Content

SIGMA detection rule by frack113, Nasreddine Bencherchali (Nextron Systems) · NOASSERTION

Detects calls to "Add-Content" cmdlet in order to modify the content of the user profile and potentially adding suspicious commands for persistence

title: Potential Persistence Via PowerShell User Profile Using Add-Content
id: 05b3e303-faf0-4f4a-9b30-46cc13e69152
status: test
description: Detects calls to "Add-Content" cmdlet in order to modify the content of the user profile and potentially adding suspicious commands for persistence
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1546.013/T1546.013.md
author: frack113, Nasreddine Bencherchali (Nextron Systems)
date: 2021-08-18
modified: 2023-05-04
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.t1546.013
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection_add:
        ScriptBlockText|contains: 'Add-Content $profile'
    selection_options:
        ScriptBlockText|contains:
            # Note: You can add more suspicious values
            - '-Value "IEX '
            - '-Value "Invoke-Expression'
            - '-Value "Invoke-WebRequest'
            - '-Value "Start-Process'
            - "-Value 'IEX "
            - "-Value 'Invoke-Expression"
            - "-Value 'Invoke-WebRequest"
            - "-Value 'Start-Process"
    condition: all of selection_*
falsepositives:
    - Legitimate administration and tuning scripts that aim to add functionality to a user PowerShell session
level: medium

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

4ac07b94-1105-4757-abe4-cd8280b59fc4

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

[[ currentRule.title ]]

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