Control: 5.2.6 Ensure that Activity Log Alert exists for Delete Network Security Group Rule

Description

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

Monitoring for Delete Network Security Group Rule events gives insight into network access changes and may reduce the time it takes to detect suspicious activity.

Remediation

From Console

1. Login to Azure Monitor console
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 Policy Assignment 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. Verify Selection preview shows All Policy assignment (policyAssignments) and your selected subscription name
10. Click Done
11. Under Condition section click Add Condition
12. Select Delete Network Security Group Rule signal
13. Click Done
14. Under Action group in Actions section, select Add action groups and complete creation process or select 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. Check Enable alert rule upon creation checkbox
18. Click Create alert rule

From Command Line

Use the below command to create an Activity Log Alert for Create or Update Network Security Groups

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_ToCreate_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,
              "equals":"Microsoft.Network/networkSecurityGroups/securityRules/delete",
              "field":"operationName"
           }
        ]
     },
     "actions":{
        "actionGroups":[
           {
              "actionGroupId":"/subscriptions/<Subscription_ID>/resourceGroups/<Resource_Group_For_Alert_Group>/providers/microsoft.insights/actionGroups/<Alert_Group>",
              "webhookProperties":null
           }
        ]
     }
  }
}

Configurable Parameters for command line:

<Resource_Group_To Create_Alert_In> <Unique_Alert_Name>

Configurable Parameters for input.json:

<Subscription_ID> in scopes
<Subscription_ID> in actionGroupId
<Resource_Group_For_Alert_Group> in actionGroupId
<Alert_Group> in actionGroupId