Windows Registry: ClickOnce Trust PromptingLevel Set to Enabled for Multiple Locations

Alerts on Enabled ClickOnce trust prompting registry changes for Internet and related locations.

FreeUnreviewedSigmamediumv1

windows-registry-clickonce-trust-promptinglevel-set-to-enabled-for-multiple-loca-ac9159cc

title: "Windows Registry: ClickOnce Trust PromptingLevel Set to Enabled for Multiple Locations"
id: 64f7e309-1d8e-4d1d-aaa5-f57258d186e8
status: test
description: This rule flags registry updates that set the ClickOnce Trust Manager PromptingLevel to Enabled for location-based trust settings such as Internet, LocalIntranet, MyComputer, TrustedSites, and UntrustedSites. Attackers can use this to alter user trust prompts and facilitate installations from different locations, weakening user and security controls. It relies on Windows registry set telemetry matching TargetObject paths under the TrustManager PromptingLevel key and a Details value of Enabled.
references:
  - https://posts.specterops.io/less-smartscreen-more-caffeine-ab-using-clickonce-for-trusted-code-execution-1446ea8051c5
  - https://learn.microsoft.com/en-us/visualstudio/deployment/how-to-configure-the-clickonce-trust-prompt-behavior
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_clickonce_trust_prompt.yml
author: "@SerkinValery, Nasreddine Bencherchali (Nextron Systems), Huntrule Team"
date: 2023-06-12
modified: 2023-08-17
tags:
  - attack.persistence
  - attack.defense-impairment
  - attack.t1112
logsource:
  category: registry_set
  product: windows
detection:
  selection:
    TargetObject|contains: \SOFTWARE\MICROSOFT\.NETFramework\Security\TrustManager\PromptingLevel\
    TargetObject|endswith:
      - \Internet
      - \LocalIntranet
      - \MyComputer
      - \TrustedSites
      - \UntrustedSites
    Details: Enabled
  condition: selection
falsepositives:
  - Legitimate internal requirements.
level: medium
license: DRL-1.1
related:
  - id: ac9159cc-c364-4304-8f0a-d63fc1a0aabb
    type: derived

What it detects

This rule flags registry updates that set the ClickOnce Trust Manager PromptingLevel to Enabled for location-based trust settings such as Internet, LocalIntranet, MyComputer, TrustedSites, and UntrustedSites. Attackers can use this to alter user trust prompts and facilitate installations from different locations, weakening user and security controls. It relies on Windows registry set telemetry matching TargetObject paths under the TrustManager PromptingLevel key and a Details value of Enabled.

Known false positives

Legitimate internal requirements.

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