huntrule

Azure Firewall Created, Modified, or Deleted via Activity Log

Alerts on Azure Firewall write or delete events in Azure Activity Logs, signaling potential defense impairment.

FreeReviewedSigma · Medium · v5
Product
azure
Service
activitylogs
Author
Austin Songer @austinsonger (SigmaHQ), DRL 1.1
Published
2021-08-08
Updated
2026-07-31
AnalysisDetection
title: Azure Firewall Created, Modified, or Deleted via Activity Log
id: 348c9da1-06a5-4024-ad91-655ad81cc9bc
status: test
description: This rule flags activity log events where an Azure Firewall resource is written or deleted. Adversaries can impair defenses by changing firewall rules or removing the firewall entirely, so these actions warrant investigation. Detection relies on Azure Activity Logs operationName values for MICROSOFT.NETWORK/AZUREFIREWALLS/WRITE and MICROSOFT.NETWORK/AZUREFIREWALLS/DELETE, which indicate firewall configuration changes or deletion.
references:
  - https://learn.microsoft.com/en-us/azure/role-based-access-control/resource-provider-operations
  - https://github.com/SigmaHQ/sigma/blob/master/rules/cloud/azure/activity_logs/azure_firewall_modified_or_deleted.yml
author: Austin Songer @austinsonger, Huntrule Team
date: 2021-08-08
modified: 2022-08-23
tags:
  - attack.impact
  - attack.defense-impairment
  - attack.t1686.001
logsource:
  product: azure
  service: activitylogs
detection:
  selection:
    operationName:
      - MICROSOFT.NETWORK/AZUREFIREWALLS/WRITE
      - MICROSOFT.NETWORK/AZUREFIREWALLS/DELETE
  condition: selection
falsepositives:
  - Firewall being modified or deleted may be performed by a system administrator. Verify whether the user identity, user agent, and/or hostname should be making changes in your environment.
  - Firewall modified or deleted from unfamiliar users should be investigated. If known behavior is causing false positives, it can be exempted from the rule.
level: medium
license: DRL-1.1
related:
  - id: 512cf937-ea9b-4332-939c-4c2c94baadcd
    type: derived