Account should have a configured activity log alert for deleting VMs

azure.activity_log
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Description

Create an activity log alert for the Delete Virtual Machine event.

Rationale

By implementing alerting on significant infrastructure changes in Microsoft Azure, you can detect unauthorized or unwanted activity.

Remediation

From the console

  1. Navigate to Monitor.
  2. Select Activity Logs.
  3. Search the operation name Delete Virtual Machine.
  4. Click On New Alert Rule.
  5. Under Scope, select the Subscription and any Resource Groups that need monitoring.
  6. Configure Action groups if needed.
  7. In Details, provide a descriptive Alert rule name and description.
  8. Go to Tags and enter relevant tags.
  9. Click Review + create.

From the command line

az account get-access-token --query "{subscription:subscription,accessToken:accessToken}" --out tsv | xargs -L1 bash -c 'curl -X PUT -H "AuthorizationBearer $1" -H "Content-Typeapplication/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"'

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

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

Using PowerShell AZ cmdlets:

$ComplianceName = 'Delete Virtual Machine'
$Signal = 'Microsoft.Compute/virtualMachines/delete'
$Category = 'Administrative'
$ResourceGroupName = 'MyResourceGroup'
$actiongroup = (Get-AzActionGroup -Name corenotifications -ResourceGroupName $ResourceGroupName)
$ActionGroupId = (New-Object Microsoft.Azure.Management.Monitor.Models.ActivityLogAlertActionGroup $ActionGroup.Id)
$Subscription = (Get-AzContext).Subscription
$location = 'Global'
$scope = "/subscriptions/$($Subscription.Id)"
$alertName = "$($Subscription.Name) - $($ComplianceName)"
$conditions = @(
  New-AzActivityLogAlertCondition -Field 'category' -Equal $Category
  New-AzActivityLogAlertCondition -Field 'operationName' -Equal $Signal
)
Set-AzActivityLogAlert -Location $location -Name $alertName -ResourceGroupName $ResourceGroupName -Scope $scope -Action $ActionGroupId -Condition $conditions

References

  1. https://docs.microsoft.com/en-us/azure/virtual-machines/windows/overview
  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.