Description

Basic Authentication provides the ability to create identities and authentication for an App Service without a centralized Identity Provider. For a more effective, capable, and secure solution for Identity, Authentication, Authorization, and Accountability, a centralized Identity Provider such as Entra ID is strongly advised.

Rationale

Basic Authentication introduces an identity silo which can produce privileged access to a resource. This can be exploited in numerous ways and represents a significant vulnerability and attack vector.

Impact

An Identity Provider that can be used by the App Service for authenticating users is required.

Audit

From Azure Portal

1. Search for, and open App Services from the search bar.
2. For each App Service listed.
3. Click on the App Service name.
4. Under the Settings menu item, click on Configuration.
5. Under the General settings tab, scroll down to locate the two Basic Auth settings:
   • SCM Basic Auth Publishing Credentials.
   • FTP Basic Auth Publishing Credentials.

Both radio buttons should indicate a status of Off.

Repeat this procedure for each App Service.

From Azure Policy

If referencing a digital copy of this Benchmark, clicking a Policy ID will open a link to the associated Policy definition in Azure.

• Policy ID: 871b205b-57cf-4e1e-a234-492616998bf7 - Name: Function apps should have authentication enabled
• Policy ID: aede300b-d67f-480a-ae26-4b3dfb1a1fdc - Name: App Service apps should have authentication enabled

Default Value

Both parameters for Basic Authentication (SCM and FTP) are set to On by default.

References

1. https://learn.microsoft.com/en-us/azure/app-service/configure-basic-auth-disable?tabs=portal