Detection rules › Sigma
Potential Rundll32 Execution With DLL Stored In ADS
Detects execution of rundll32 where the DLL being called is stored in an Alternate Data Stream (ADS).
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 1: Process creation |
Rule body
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
Stages and Predicates
Stage 0: condition
all of selection_*Stage 1: selection_img
selection_img:
- Image|endswith: '\rundll32.exe'
- OriginalFileName: 'RUNDLL32.EXE'
Stage 2: selection_cli
selection_cli:
CommandLine|re: '[Rr][Uu][Nn][Dd][Ll][Ll]32(?:\.[Ee][Xx][Ee])? \S+?\w:\S+?:'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
CommandLine | regex_match |
| field:"CommandLine" kind:regex_match value:"[Rr][Uu][Nn][Dd][Ll][Ll]32(?:.[Ee][Xx][Ee])? \S+?\w:\S+?:" |
Image | ends_with |
| field:"Image" kind:ends_with value:"\rundll32.exe" |
OriginalFileName | eq |
| field:"OriginalFileName" kind:eq value:"RUNDLL32.EXE" |