Ensure Basic SCM/FTP Authentication is 'Disabled' for App Service

Overview

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 to authenticate users is required.

Remediation guidance

Remediate from Azure Portal

Open the web app using the Open in Azure button.
Under the Settings menu item, click on Configuration
Under the General settings tab, scroll down to locate the two Basic Auth settings:

Set the SCM Basic Auth Publishing Credentials radio button to Off
Set the FTP Basic Auth Publishing Credentials radio button to Off

CAUTION: The new settings are not yet applied. Applying them may cause your App Service resource to restart - proceed with caution. Click the Save button, then click Continue to apply the updated configuration.

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 App Service sites allowing basic publishing auth

Connectors

Microsoft Azure

Covered asset types

Site

Expected check: eq []

{
  sites(
    where: {
      basicPublishingCredentials_SOME: {
        OR: [{ name: "ftp", allowed: true }, { name: "scm", allowed: true }]
      }
    }
  ) {
    ...AssetFragment
  }
}