9.1 Ensure 'HTTPS Only' is set to 'On'

Information

Azure App Service allows apps to run under both HTTP and HTTPS by default. Apps can be accessed by anyone using non-secure HTTP links by default. Non-secure HTTP requests can be restricted and all HTTP requests redirected to the secure HTTPS port. It is recommended to enforce HTTPS-only traffic.

Rationale:

Enabling HTTPS-only traffic will redirect all non-secure HTTP requests to HTTPS ports. HTTPS uses the TLS/SSL protocol to provide a secure connection which is both encrypted and authenticated. It is therefore important to support HTTPS for the security benefits.

Impact:

When it is enabled, every incoming HTTP request is redirected to the HTTPS port. This means an extra level of security will be added to the HTTP requests made to the app.

Solution

Remediate from Azure Portal

Login to Azure Portal using https://portal.azure.com

Go to App Services

For each App Service

Under Setting section, click on Configuration

Under the General Settings tab, set HTTPS Only to On under Platform Settings

Remediate from Azure CLI
To set HTTPS-only traffic value for an existing app, run the following command:

az webapp update --resource-group <RESOURCE_GROUP_NAME> --name <APP_NAME> --set httpsOnly=true

Remediate from PowerShell

Set-AzWebApp -ResourceGroupName <RESOURCE_GROUP_NAME> -Name <APP_NAME> -HttpsOnly $true

Default Value:

By default, HTTPS-only feature will be disabled when a new app is created using the command-line tool or Azure Portal console.

See Also

https://workbench.cisecurity.org/benchmarks/16820

Item Details

Category: ACCESS CONTROL, IDENTIFICATION AND AUTHENTICATION, SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|AC-17(2), 800-53|IA-5, 800-53|IA-5(1), 800-53|SC-8, 800-53|SC-8(1), CSCv7|14.4

Plugin: microsoft_azure

Control ID: eb9d40047e5f1b2f12051f92e065e95796a258a337a3ebf75ffc0216468c54d4