Potential Rundll32 Execution With DLL Stored In ADS — Sigma Rule

Rule metadata and linked tags

Author: Harjot Singh, '@cyb3rjy0t'. Source status: test; severity: high. Source dates: 2023-01-21 / 2026-03-16.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 79c31422095b2d77939530abcbf60c3c0b64cd6dfc6eef1a16f3150f79f8fa8a

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Potential Rundll32 Execution With DLL Stored In ADS
id: 9248c7e1-2bf3-4661-a22c-600a8040b446
status: test
description: Detects execution of rundll32 where the DLL being called is stored in an Alternate Data Stream (ADS).
references:
    - https://lolbas-project.github.io/lolbas/Binaries/Rundll32
author: Harjot Singh, '@cyb3rjy0t'
date: 2023-01-21
modified: 2026-03-16
tags:
    - attack.stealth
    - attack.t1564.004
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\rundll32.exe'
        - OriginalFileName: 'RUNDLL32.EXE'
    selection_cli:
        # Example:
        #   rundll32 "C:\ads\file.txt:ADSDLL.dll",DllMain
        # Note: This doesn't cover the use case where a full path for the DLL isn't used. As it requires a more expensive regex
        CommandLine|re: '[Rr][Uu][Nn][Dd][Ll][Ll]32(?:\.[Ee][Xx][Ee])? \S+?\w:\S+?:'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://lolbas-project.github.io/lolbas/Binaries/Rundll32