Windows: Suspicious rundll32 Execution of advpack.dll with Ordinal RegisterOCX Calls

Identifies rundll32.exe launching advpack.dll with ordinal-style calls consistent with stealthy OCX registration behavior.

FreeUnreviewedSigmahighv1

windows-suspicious-rundll32-execution-of-advpack-dll-with-ordinal-registerocx-ca-a1473adb

title: "Windows: Suspicious rundll32 Execution of advpack.dll with Ordinal RegisterOCX Calls"
id: 80f3491e-f582-475d-ae79-9dc9291566bb
status: test
description: This rule flags process creation where rundll32.exe is launched with command-line arguments indicating advpack.dll usage and an ordinal-based call pattern. Attackers can use this behavior to stealthily trigger COM/OCX registration via the advpack RegisterOCX function, potentially aiding persistence or execution flow. The detection relies on Windows process creation telemetry, matching rundll32-related image details, advpack string presence, and specific ordinal call indicators in the command line.
references:
  - https://twitter.com/Hexacorn/status/1224848930795552769
  - http://www.hexacorn.com/blog/2020/02/05/stay-positive-lolbins-not/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_rundll32_advpack_obfuscated_ordinal_call.yml
author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2023-05-17
tags:
  - attack.stealth
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith: \rundll32.exe
    - OriginalFileName: RUNDLL32.EXE
    - CommandLine|contains: rundll32
  selection_cli_dll:
    CommandLine|contains: advpack
  selection_cli_ordinal:
    - CommandLine|contains|all:
        - "#+"
        - "12"
    - CommandLine|contains: "#-"
  condition: all of selection_*
falsepositives:
  - Unlikely
level: high
license: DRL-1.1
related:
  - id: a1473adb-5338-4a20-b4c3-126763e2d3d3
    type: derived

What it detects

This rule flags process creation where rundll32.exe is launched with command-line arguments indicating advpack.dll usage and an ordinal-based call pattern. Attackers can use this behavior to stealthily trigger COM/OCX registration via the advpack RegisterOCX function, potentially aiding persistence or execution flow. The detection relies on Windows process creation telemetry, matching rundll32-related image details, advpack string presence, and specific ordinal call indicators in the command line.

Known false positives

Unlikely

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.