Cis Azure Compute 2.1.9

Ensure end-to-end TLS encryption is enabled

Description

End-to-end (E2E) TLS encryption ensures that front-end to worker communication within App Service apps is encrypted using TLS. Without this feature, while incoming HTTPS requests are encrypted to the front ends, the traffic from front ends to workers running the application workloads would travel unencrypted inside Azure's infrastructure.

Rationale

E2E TLS helps ensure full encryption of traffic between:

• Clients and front ends
• Front ends and worker processes hosting the application

Impact

Enabling end-to-end TLS encryption may introduce minimal latency and require additional configuration of certificates and HTTPS settings to ensure compatibility.

Audit Procedure

Using Azure Portal

1. Go to App Services.
2. Click the name of an app.
3. Under Settings, click Configuration.
4. In the General settings pane, under Platform settings, ensure that Enable end-to-end TLS encryption is set to On.
5. Repeat steps 1-4 for each app.

Using Azure CLI

Run the following command to list apps:

az webapp list

For each app, run the following command to get the end-to-end TLS encryption setting:

az webapp show --resource-group <resource-group-name> --name <app-name> --query endToEndEncryptionEnabled

Ensure that the command returns true.

Using Azure PowerShell

Not specifically documented for this control.

Expected Result

The endToEndEncryptionEnabled setting should return true.

Remediation

Using Azure Portal

1. Go to App Services.
2. Click the name of an app.
3. Under Settings, click Configuration.
4. In the General settings pane, under Platform settings, next to Enable end-to-end TLS encryption, click the radio button next to On.
5. Click Save.
6. Click Continue.
7. Repeat steps 1-6 for each app requiring remediation.

Using Azure CLI

For each app requiring remediation, run the following command to enable end-to-end TLS encryption:

az resource update --resource-group <resource-group-name> --name <app-name> --resource-type "Microsoft.Web/sites" --set properties.endToEndEncryptionEnabled=true

Using Azure PowerShell

Not specifically documented for this control.

Default Value

By default, end-to-end TLS encryption is disabled.

References

1. https://learn.microsoft.com/en-us/azure/app-service/overview-tls#end-to-end-tls-encryption
2. https://learn.microsoft.com/en-us/cli/azure/webapp
3. https://learn.microsoft.com/en-us/cli/azure/resource

Profile

Level 1 | Automated