Ensure a 'Diagnostic Setting' exists for Subscription Activity Logs

Overview

Enable Diagnostic settings for exporting activity logs.

Diagnostic settings are available for each individual resource within a subscription. You should configure settings for all appropriate resources in your environment.

Rationale

A diagnostic setting controls how a diagnostic log is exported. By default, logs are retained only for 90 days. Diagnostic settings should be defined so that logs can be exported and stored longer to analyze security activities within an Azure subscription.

Remediation guidance

Remediate from Azure Portal

To enable Diagnostic Settings on a subscription:

Go to Monitor
Click on Activity log
Click on Export Activity Logs
Click + Add diagnostic setting
Enter a Diagnostic setting name
Select Categories for the diagnostic setting
Select the appropriate Destination details (this may be Log Analytics, Storage Account, Event Hub, or Partner solution)
Click Save

Remediate from Azure CLI

To configure Diagnostic Settings on a subscription:

az monitor diagnostic-settings subscription create --subscription <subscription id> --name <diagnostic settings name> --location <location> <[--event-hub <event hub ID> --event-hub-auth-rule <event hub auth rule ID>] [--storage-account <storage account ID>] [--workspace <log analytics workspace ID>] --logs "" (e.g. [{category:Security,enabled:true},{category:Administrative,enabled:true},{category:Alert,enabled:true},{category:Policy,enabled:true}])

Remediate from PowerShell

To configure Diagnostic Settings on a subscription:

$logCategories = @();
$logCategories += New-AzDiagnosticSettingSubscriptionLogSettingsObject -Category Administrative -Enabled $true
$logCategories += New-AzDiagnosticSettingSubscriptionLogSettingsObject -Category Security -Enabled $true
$logCategories += New-AzDiagnosticSettingSubscriptionLogSettingsObject -Category Alert -Enabled $true
$logCategories += New-AzDiagnosticSettingSubscriptionLogSettingsObject -Category Policy -Enabled $true

New-AzSubscriptionDiagnosticSetting -SubscriptionId <subscription ID> -Name  <[-EventHubAuthorizationRule <event hub auth rule ID> -EventHubName <event hub name>] [-StorageAccountId <storage account ID>] [-WorkSpaceId <log analytics workspace ID>] [-MarketplacePartner ID <full ARM Marketplace resource ID>]> -Log $logCategories

Multiple Remediation Paths

Azure

SERVICE-WIDE (RECOMMENDED when many resources are affected): Assign Azure Policy initiatives at management group/subscription scope and trigger remediation tasks.

az policy assignment create --name <assignment-name> --scope /subscriptions/<subscription-id> --policy-set-definition <initiative-id>
az policy remediation create --name <remediation-name> --policy-assignment <assignment-id>

ASSET-LEVEL: Apply the resource-specific remediation steps above to the listed non-compliant resources.

PREVENTIVE: Embed Azure Policy checks into landing zones and IaC workflows to block or auto-remediate drift.

References for Service-Wide Patterns

Azure Policy overview: https://learn.microsoft.com/en-us/azure/governance/policy/overview
Azure Policy remediation: https://learn.microsoft.com/en-us/azure/governance/policy/how-to/remediate-resources
Azure Policy initiative structure: https://learn.microsoft.com/en-us/azure/governance/policy/concepts/initiative-definition-structure

Operational Rollout Workflow

Use this sequence to reduce risk and avoid repeated drift.

1. Contain at Service-Wide Scope First (Recommended)

Azure: assign policy initiatives at management group/subscription scope and run remediation tasks.

az policy assignment create --name <assignment-name> --scope /subscriptions/<subscription-id> --policy-set-definition <initiative-id>
az policy remediation create --name <remediation-name> --policy-assignment <assignment-id>

2. Remediate Existing Affected Assets

Execute the control-specific Console/CLI steps documented above for each flagged resource.
Prioritize internet-exposed and production assets first.

3. Validate and Prevent Recurrence

Re-scan after each remediation batch.
Track exceptions with owner and expiry date.
Add preventive checks in IaC/CI pipelines.

Query logic

These are the stored checks tied to this control.

Azure subscriptions without diagnostic settings

Connectors

Microsoft Azure

Covered asset types

SubscriptionDiagnosticSettings

Expected check: eq []

{
  subscriptionDiagnosticSettings(
    where: {
      OR: [
        { logSettings_SOME: null }
        {
          logSettings_SOME: {
            category_IN: ["Administrative", "Alert", "Policy", "Security"]
            enabled: false
          }
        }
      ]
    }
  ) {
    ...AssetFragment
  }
}