Account should have a configured activity log alert for deleting Network Security Group

Warning: This rule will be deprecated 18 December 2023 as part of the update to Azure CIS version 2.0.0

Description

Create an activity log alert for the Delete Network Security Group event.

Rationale

By monitoring for delete betwork security group events, you gain insight into network access changes and may reduce the time it takes to detect suspicious activity.

Remediation

From the console

  1. Navigate to Monitor.

  2. Select Alerts.

  3. Click On New Alert Rule.

  4. Under Scope, click Select resource.

  5. Select the appropriate subscription under Filter by subscription.

  6. Select Network Security Groups under Filter by resource type.

  7. Select All for Filter by location.

  8. Click on the subscription resource from the entries populated under Resource.

  9. Click Done.

  10. Verify that Selection preview shows Network Security Groups and your selected subscription name

  11. Under Condition, click Add Condition.

  12. Select Delete Network Security Group signal.

  13. Click Done.

  14. Under Action group, select Add action groups and either complete the creation process, or select the appropriate action group.

  15. Under Alert rule details, enter Alert rule name and Description.

  16. Select appropriate resource group to save the alert to.

  17. Click on the Enable alert rule upon creation checkbox.

  18. Click Create alert rule.

From the command line

az account get-access-token --query "{subscription:subscription,accessToken:accessToken}" --out tsv | xargs -L1 bash -c 'curl -X PUT -H "Authorization: Bearer $1" -H "Content-Type: application/json" https://management.azure.com/subscriptions/$0/resourceGroups/<Resource_Group_ To_Create_Alert_In>/providers/microsoft.insights/activityLogAlerts/<Unique_Alert _Name>?api-version=2017-04-01 -d@"input.json"'

Where input.json contains the request body JSON data as mentioned below.

{
  "location": "Global",
  "tags": {},
  "properties": {
    "scopes": [
      "/subscriptions/<Subscription_ID>"
    ],
    "enabled": true,
    "condition": {
      "allOf": [
        {
          "containsAny": null,
          "equals": "Administrative",
          "field": "category"
        },
        {
          "containsAny": null,
          "field": "operationName",
          "equals": "Microsoft.Network/networkSecurityGroups/delete"
        }
      ]
    },
    "actions": {
      "actionGroups": [
        {
          "actionGroupId": "/subscriptions/<Subscription_ID>/resourceGroups/<Resource_Group_For_Alert_Gr oup>/providers/microsoft.insights/actionGroups/<Alert_Group>",
          "webhookProperties": null
        }
      ]
    },
  }
}

References

  1. https://azure.microsoft.com/en-us/updates/classic-alerting-monitoring-retirement
  2. https://docs.microsoft.com/en-in/azure/azure-monitor/platform/alerts-activity-log
  3. https://docs.microsoft.com/en-in/rest/api/monitor/activitylogalerts/createorupdate
  4. https://docs.microsoft.com/en-in/rest/api/monitor/activitylogalerts/listbysubscriptionid
  5. https://docs.microsoft.com/en-us/azure/security/benchmarks/security-controls-v2-logging-threat-detection#lt-4-enable-logging-for-azure-resources

CIS Controls

Version 7, 6.3 - Enable Detailed Logging: Enable system logging to include detailed information such as an event source, date, user, timestamp, source addresses, destination addresses, and other useful elements.