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Detection rules › Sigma

Potential Binary Or Script Dropper Via PowerShell

Status
test
Severity
medium
Log source
product windows, category file_event
Author
frack113, Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects PowerShell creating a binary executable or a script file.

MITRE ATT&CK coverage

TacticTechniques
PersistenceNo specific technique

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

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

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_main_*

Stage 1: selection

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'

Stage 2: not filter_main_*

filter_main_user_temp:
    TargetFilename|startswith: 'C:\Users\'
    TargetFilename|contains: '\AppData\Local\Temp\'
    TargetFilename|endswith:
        - '.dll'
        - '.exe'
filter_main_other_temp:
    TargetFilename|startswith:
        - 'C:\Windows\Temp\'
        - 'C:\Windows\SystemTemp\'
    TargetFilename|endswith:
        - '.dll'
        - '.exe'
filter_main_powershell_module:
    TargetFilename|startswith: 'C:\Users\'
    TargetFilename|contains: '\WindowsPowerShell\Modules\'
    TargetFilename|endswith: '.dll'
filter_main_nuget:
    TargetFilename|startswith: 'C:\Program Files\PackageManagement\ProviderAssemblies\nuget\'
    TargetFilename|endswith: '\Microsoft.PackageManagement.NuGetProvider.dll'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
TargetFilenameends_with.dll
TargetFilenameends_with.exe
TargetFilenamestarts_withC:\Windows\SystemTemp\
TargetFilenamestarts_withC:\Windows\Temp\
TargetFilenameends_with.dll
TargetFilenameends_with.exe
TargetFilenamematch\AppData\Local\Temp\
TargetFilenamestarts_withC:\Users\
TargetFilenameends_with.dll
TargetFilenamematch\WindowsPowerShell\Modules\
TargetFilenamestarts_withC:\Users\
TargetFilenameends_with\Microsoft.PackageManagement.NuGetProvider.dll
TargetFilenamestarts_withC:\Program Files\PackageManagement\ProviderAssemblies\nuget\

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Imageends_with
  • \powershell.exe corpus 182 (sigma 182)
  • \powershell_ise.exe corpus 41 (sigma 41)
  • \pwsh.exe corpus 168 (sigma 168)
TargetFilenameends_with
  • .bat corpus 17 (sigma 17)
  • .chm corpus 3 (sigma 3)
  • .cmd corpus 8 (sigma 8)
  • .com corpus 3 (sigma 3)
  • .dll corpus 23 (sigma 23)
  • .exe corpus 21 (sigma 20, splunk 1)
  • .hta corpus 13 (sigma 13)
  • .jar corpus 2 (sigma 2)
  • .js corpus 9 (sigma 9)
  • .ocx corpus 3 (sigma 3)
  • .scr corpus 8 (sigma 8)
  • .sys corpus 6 (sigma 6)
  • .vbe corpus 15 (sigma 15)
  • .vbs corpus 18 (sigma 18)
  • .wsf corpus 7 (sigma 7)