Windows AddInUtil.exe Executed with Suspicious AddInRoot or PipelineRoot Parameters

Alerts on AddInUtil.exe runs using uncommon AddInRoot/PipelineRoot values targeting Temp, Desktop, Downloads, or public user paths.

FreeReviewedSigma · High · v2

Product: windows
Category: process_creation
Author: Nasreddine Bencherchali (Nextron Systems), Michael McKinley (@McKinleyMike), Tony Latteri (@TheLatteri) (SigmaHQ), DRL 1.1
Published: 2023-09-18
Updated: 2026-07-31

Analysis Detection

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218System Binary Proxy Execution
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags process creation events where AddInUtil.exe is executed with command-line parameters specifying AddInRoot or PipelineRoot values that include uncommon, user-writable paths (e.g., AppData\Local\Temp, Desktop, Downloads, Users\Public, Windows\Temp) or dot-based relative roots. Attackers may use AddInUtil.exe to load or point to attacker-controlled Addins.Store payloads by providing atypical root paths. The detection relies on Windows process creation telemetry, specifically the executable name and the full command line and current directory.

Reporting behind it

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Windows AddInUtil.exe Executed with Suspicious AddInRoot or PipelineRoot Parameters

Pivot detection · T1218 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

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

windows-process-creation-addinutil-exe-with-suspicious-addinroot-pipelineroot-pa-631b22a4

title: Windows AddInUtil.exe Executed with Suspicious AddInRoot or PipelineRoot Parameters
id: ceadd7ce-3963-4f89-af48-73e405856ef7
status: test
description: This rule flags process creation events where AddInUtil.exe is executed with command-line parameters specifying AddInRoot or PipelineRoot values that include uncommon, user-writable paths (e.g., AppData\Local\Temp, Desktop, Downloads, Users\Public, Windows\Temp) or dot-based relative roots. Attackers may use AddInUtil.exe to load or point to attacker-controlled Addins.Store payloads by providing atypical root paths. The detection relies on Windows process creation telemetry, specifically the executable name and the full command line and current directory.
references:
  - https://www.blue-prints.blog/content/blog/posts/lolbin/addinutil-lolbas.html
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_addinutil_suspicious_cmdline.yml
author: Nasreddine Bencherchali (Nextron Systems), Michael McKinley (@McKinleyMike), Tony Latteri (@TheLatteri), Huntrule Team
date: 2023-09-18
tags:
  - attack.stealth
  - attack.t1218
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith: \addinutil.exe
    - OriginalFileName: AddInUtil.exe
  selection_susp_1_flags:
    CommandLine|contains:
      - "-AddInRoot:"
      - "-PipelineRoot:"
  selection_susp_1_paths:
    CommandLine|contains:
      - \AppData\Local\Temp\
      - \Desktop\
      - \Downloads\
      - \Users\Public\
      - \Windows\Temp\
  selection_susp_2:
    CommandLine|contains:
      - -AddInRoot:.
      - -AddInRoot:"."
      - -PipelineRoot:.
      - -PipelineRoot:"."
    CurrentDirectory|contains:
      - \AppData\Local\Temp\
      - \Desktop\
      - \Downloads\
      - \Users\Public\
      - \Windows\Temp\
  condition: selection_img and (all of selection_susp_1_* or selection_susp_2)
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: 631b22a4-70f4-4e2f-9ea8-42f84d9df6d8
    type: derived

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