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Enable Microsoft Defender for Cloud for App Service Instances

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Risk Level: High (not acceptable risk)
Rule ID: SecurityCenter-033

Ensure that Microsoft Defender for Cloud is enabled for the Microsoft Azure App Service instances. Turning on Defender for Cloud enables threat detection for Azure App Service, providing threat intelligence, anomaly detection, and behavior analytics.

This rule resolution is part of the Conformity Security & Compliance tool for Azure.

Security

By default, Microsoft Defender for Cloud is not enabled for your App Service instances. Enabling the Defender security service for App Service instances allows for advanced security defense using threat detection capabilities provided by Microsoft Security Response Center.


Audit

To determine if the Microsoft Defender for Cloud security service is enabled for your App Service instances, perform the following operations:

Using Azure Portal

01 Sign in to the Microsoft Azure Portal.

02 Navigate to Microsoft Defender for Cloud blade at https://portal.azure.com/#blade/Microsoft_Azure_Security/SecurityMenuBlade/0.

03 In the main navigation panel, under Management, choose Environment settings.

04 Click on the name (link) of the Azure subscription that you want to examine.

05 In the navigation panel, under Settings, choose Defender plans to access the Defender for Cloud pricing plans available for the selected subscription.

06 On the Defender plans page, check the Defender for Cloud pricing plan status available for the App Service resource type, listed in the Plan column. If the pricing plan status for App Service is set to Off, Microsoft Defender for Cloud is not enabled for the Azure App Service instances available in the selected subscription.

07 Repeat step no. 4 – 6 for each Microsoft Azure subscription available within your cloud account.

Using Azure CLI

01 Run account get-access-token command (Windows/macOS/Linux) with custom query filters to describe the name of the Defender for Cloud pricing plan configured for the App Service instances available within the current subscription:

az account get-access-token
  --query "{subscription:subscription,accessToken:accessToken}"
  --out tsv | xargs -L1 bash -c 'curl -X GET -H "Authorization: Bearer $1" -H "Content-Type: application/json" https://management.azure.com/subscriptions/$0/providers/Microsoft.Security/pricings?api-version=2018-06-01' | jq '.|.value[] | select(.name=="AppServices")'|jq '.properties.pricingTier'

02 The command output should return the name of the configured pricing tier:

"Free"

If the account get-access-token command output does not return "Standard" for the name of the pricing tier, Microsoft Defender for Cloud is not enabled for the Azure App Service instances deployed within the current subscription.

03 Repeat steps no. 1 and 2 for each Microsoft Azure subscription available in your cloud account.

Remediation / Resolution

To enable Microsoft Defender for Cloud for your Azure App Service instances, perform the following operations:

Note: Turning on Defender for Cloud for the specified resource type (i.e. App Service instances) incurs an additional cost per resource.

Using Azure Portal

01 Sign in to the Microsoft Azure Portal.

02 Navigate to Microsoft Defender for Cloud blade at https://portal.azure.com/#blade/Microsoft_Azure_Security/SecurityMenuBlade/0.

03 In the main navigation panel, under Management, choose Environment settings.

04 Click on the name (link) of the Azure subscription that you want to access.

05 In the navigation panel, under Settings, choose Defender plans to access the Defender for Cloud pricing plans available for the selected subscription.

06 On the Defender plans configuration page, under Microsoft Defender for, choose On for the App Service pricing plan listed in the Plan column, to enable Microsoft Defender for Cloud for Azure App Service instances. Choose Save from the top menu to apply the changes.

07 Repeat step no. 4 – 6 for each Microsoft Azure subscription available within your cloud account.

Using Azure CLI

01 Define the configuration parameters for the account get-access-token command, where the "pricingTier" parameter value is set to "Standard" to turn on the Defender for Cloud pricing plan for App Service instances. Save the configuration document to a JSON file named enable-defender-for-app-services.json and replace the highlighted details, i.e. <azure-subscription-id>, with your own Azure account subscription ID:

{
  "id": "/subscriptions/<azure-subscription-id>/providers/Microsoft.Security/pricings/AppServices",
  "name": "AppServices",
  "type": "Microsoft.Security/pricings",
  "properties": {
    "pricingTier": "Standard"
  }
}

02 Run account get-access-token command (Windows/macOS/Linux) using the configuration document defined at the previous step (i.e. enable-defender-for-app-services.json file), to enable Microsoft Defender for Cloud for the Azure App Service instances deployed in the selected subscription:

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/providers/Microsoft.Security/pricings/AppServices?api-version=2018-06-01 -d@"enable-defender-for-app-services.json"'

03 The command output should return the information available for the enabled pricing tier:

{
  "id": "/subscriptions/abcd1234-abcd-1234-abcd-1234abcd1234/providers/Microsoft.Security/pricings/AppServices",
  "name": "AppServices",
  "type": "Microsoft.Security/pricings",
  "properties": {
    "pricingTier": "Standard",
    "freeTrialRemainingTime": "PT0S"
  }
}

04 Repeat steps no. 1 – 3 for each Microsoft Azure subscription available in your cloud account.

References

Publication date Feb 19, 2022