Azure Activity Logs: Virtual Network Modified or Deleted

title: "Azure Activity Logs: Virtual Network Modified or Deleted"
id: 18f17db3-299f-4d96-9cdb-882bd6c5b06f
status: test
description: This rule flags Azure Activity Log events where a Virtual Network or Virtual Network Gateway operation is either written or deleted. Such actions can disrupt connectivity and expose an environment to availability and impact risks, whether changes are malicious or accidental. It relies on the Activity Logs operationName prefixes for Microsoft Network Virtual Network and Virtual Network Gateways, and operationName suffixes indicating WRITE or DELETE.
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_virtual_network_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|startswith:
      - MICROSOFT.NETWORK/VIRTUALNETWORKGATEWAYS/
      - MICROSOFT.NETWORK/VIRTUALNETWORKS/
    operationName|endswith:
      - /WRITE
      - /DELETE
  condition: selection
falsepositives:
  - Virtual Network 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.
  - Virtual Network 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: bcfcc962-0e4a-4fd9-84bb-a833e672df3f
    type: derived