Control: 9.9 Ensure that 'HTTP Version' is the latest, if used to run the web app

Description

Periodically, newer versions are released for HTTP either due to security flaws or to include additional functionality. Using the latest HTTP version for web apps to take advantage of security fixes, if any, and/or new functionalities of the newer version.

Newer versions may contain security enhancements and additional functionality. With each software installation, organizations need to determine if a given update meets their requirements and also verify the compatibility and support provided for any additional software against the update revision that is selected.

HTTP 2.0 has additional performance improvements on the head-of-line blocking problem of old HTTP version, header compression, and prioritization of requests. HTTP 2.0 no longer supports HTTP 1.1's chunked transfer encoding mechanism, as it provides its own, more efficient, mechanisms for data streaming.

Remediation

From Console

Perform the following action to check latest version installed:

1. Login to Azure Portal and go to App Services.
2. Click on each App.
3. Under Settings section, click on Configuration.
4. Go to General settings tab.
5. Under Platform settings, ensure HTTP version is set to 0.2.
6. Click Save.

Note Most modern browsers support HTTP 2.0 protocol over TLS only, while non- encrypted traffic continues to use HTTP 1.1. To ensure that client browsers connect to your app with HTTP/2, either buy an App Service Certificate for your app's custom domain or bind a third party certificate.

From Command Line

To set HTTP 2.0 version for an existing app, run the following command:

az webapp config set --resource-group <RESOURCE_GROUP_NAME> --name <APP_NAME> --http20-enabled true