Windows IIS Configuration: Disable ETW Logging/Processing via logTargetW3C Change

Identifies IIS configuration edits that remove/disable ETW logging or processing for W3C log targeting.

FreeReviewedSigma · Medium · v2
Product
windows
Service
iis-configuration
Author
frack113, Nasreddine Bencherchali (SigmaHQ), DRL 1.1
Published
2024-10-06
Updated
2026-07-31
title: "Windows IIS Configuration: Disable ETW Logging/Processing via logTargetW3C Change"
id: 4cc385de-f9cd-48ef-92c8-e1a38a7d296f
status: test
description: This rule identifies IIS configuration updates that disable or remove ETW-related logging/processing by changing the log target setting. Attackers may do this to reduce or disrupt forensic telemetry and hinder detection while maintaining web access. The detection relies on IIS configuration change events (EventID 29) with prior and updated configuration values involving '@logTargetW3C' and ETW.
references:
  - https://learn.microsoft.com/en-us/iis/manage/provisioning-and-managing-iis/configure-logging-in-iis
  - https://www.microsoft.com/en-us/security/blog/2022/12/12/iis-modules-the-evolution-of-web-shells-and-how-to-detect-them/
  - https://learn.microsoft.com/en-us/iis/configuration/system.applicationhost/sites/sitedefaults/logfile/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/iis-configuration/win_iis_logging_etw_disabled.yml
author: frack113, Nasreddine Bencherchali, Huntrule Team
date: 2024-10-06
tags:
  - attack.persistence
  - attack.defense-impairment
  - attack.t1685.001
  - attack.t1505.004
logsource:
  product: windows
  service: iis-configuration
detection:
  selection:
    EventID: 29
    Configuration|endswith: "@logTargetW3C"
    OldValue|contains: ETW
  filter_main_etw_added:
    NewValue|contains: ETW
  condition: selection and not 1 of filter_main_*
falsepositives:
  - Legitimate administrator activity
level: medium
license: DRL-1.1
related:
  - id: a5b40a90-baf5-4bf7-a6f7-373494881d22
    type: derived