PowerShell Write-EventLog Usage

SIGMA detection rule by Nasreddine Bencherchali (Nextron Systems) · GPL-2.0

Detects usage of the "Write-EventLog" cmdlet with 'RawData' flag. The cmdlet can be levreage to write malicious payloads to the EventLog and then retrieve them later for later use

title: PowerShell Write-EventLog Usage
id: 777d9383-7a6f-f82a-d22e-2f05f433bc9b
related:
    - id: 35f41cd7-c98e-469f-8a02-ec4ba0cc7a7e
      type: derived
status: test
description: Detects usage of the "Write-EventLog" cmdlet with 'RawData' flag. The cmdlet can be levreage to write malicious payloads to the EventLog and then retrieve them later for later use
references:
    - https://www.blackhillsinfosec.com/windows-event-logs-for-red-teams/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-08-16
tags:
    - attack.defense-impairment
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    ps_script:
        EventID: 4104
        Channel:
            - Microsoft-Windows-PowerShell/Operational
            - PowerShellCore/Operational
    selection:
        ScriptBlockText|contains|all:
            - Write-EventLog
            - '-RawData '
    condition: ps_script and selection
falsepositives:
    - Legitimate applications writing events via this cmdlet. Investigate alerts to determine if the action is benign
level: medium
ruletype: Sigma

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

3d74ac3b-8078-4ddc-982e-0f4f76367386

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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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