Azure Firewall Rule Configuration Modified or Deleted via Activity Logs

title: Azure Firewall Rule Configuration Modified or Deleted via Activity Logs
id: 5a0cffc6-9865-4aad-b08a-cbdfad810aee
status: test
description: This rule identifies Azure Activity Log events where firewall rule configurations are modified or deleted. Such changes can disrupt network access and policy enforcement, making them valuable to attackers seeking to impact connectivity or evade controls. The detection relies on operationName values in Azure Activity Logs covering write and delete operations for firewall policy rule collection groups and rule groups.
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_network_firewall_rule_modified_or_deleted.yml
author: Austin Songer @austinsonger, Huntrule Team
date: 2021-08-08
modified: 2022-08-23
tags:
  - attack.impact
logsource:
  product: azure
  service: activitylogs
detection:
  selection:
    operationName:
      - MICROSOFT.NETWORK/FIREWALLPOLICIES/RULECOLLECTIONGROUPS/WRITE
      - MICROSOFT.NETWORK/FIREWALLPOLICIES/RULECOLLECTIONGROUPS/DELETE
      - MICROSOFT.NETWORK/FIREWALLPOLICIES/RULEGROUPS/WRITE
      - MICROSOFT.NETWORK/FIREWALLPOLICIES/RULEGROUPS/DELETE
  condition: selection
falsepositives:
  - Firewall Rule Configuration 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 Rule Configuration 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: 2a7d64cf-81fa-4daf-ab1b-ab80b789c067
    type: derived