Potential Binary Or Script Dropper Via PowerShell

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

Detects PowerShell creating a binary executable or a script file.

title: Potential Binary Or Script Dropper Via PowerShell
id: 7047d730-036f-4f40-b9d8-1c63e36d5e62
status: test
description: Detects PowerShell creating a binary executable or a script file.
references:
    - https://www.zscaler.com/blogs/security-research/onenote-growing-threat-malware-distribution
author: frack113, Nasreddine Bencherchali (Nextron Systems)
date: 2023-03-17
modified: 2025-07-04
tags:
    - attack.persistence
logsource:
    product: windows
    category: file_event
detection:
    selection:
        Image|endswith:
            - '\powershell.exe'
            - '\powershell_ise.exe'
            - '\pwsh.exe'
        TargetFilename|endswith:
            - '.bat'
            - '.chm'
            - '.cmd'
            - '.com'
            - '.dll'
            - '.exe'
            - '.hta'
            - '.jar'
            - '.js'
            - '.ocx'
            - '.scr'
            - '.sys'
            - '.vbe'
            - '.vbs'
            - '.wsf'
    filter_main_user_temp:
        TargetFilename|startswith: 'C:\Users\'
        TargetFilename|contains: '\AppData\Local\Temp\'
        TargetFilename|endswith:
            - '.dll'
            - '.exe'
    filter_main_other_temp:
        # Example: C:\Windows\Temp\0DA9758B-4649-4969-9409-5CBDF193FB53\TransmogProvider.dll
        TargetFilename|startswith:
            - 'C:\Windows\Temp\'
            - 'C:\Windows\SystemTemp\'
        TargetFilename|endswith:
            - '.dll'
            - '.exe'
    filter_main_powershell_module:
        TargetFilename|startswith: 'C:\Users\'
        TargetFilename|contains: '\WindowsPowerShell\Modules\' # C:\Users\xxxx\Documents\WindowsPowerShell\Modules\powershell-yaml\0.4.12\lib\net47\PowerShellYamlSerializer.dll
        TargetFilename|endswith: '.dll'
    filter_main_nuget:
        TargetFilename|startswith: 'C:\Program Files\PackageManagement\ProviderAssemblies\nuget\'
        TargetFilename|endswith: '\Microsoft.PackageManagement.NuGetProvider.dll'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - False positives will differ depending on the environment and scripts used. Apply additional filters accordingly.
level: medium
regression_tests_path: regression_data/rules/windows/file/file_event/file_event_win_powershell_drop_binary_or_script/info.yml

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

5f479383-0d99-46e1-b426-2f5d4fb4b586

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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.

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Format & documentation suggestions

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