cis-azure-compute-2-3-8

name	cis-azure-compute-2.3.8
description	Ensure end-to-end TLS encryption is enabled
category	cis-azure-compute
version	2.0.0
author	cyberstrike-official
tags	["cis","azure","function-apps","tls","e2e-encryption","data-in-transit"]
cis_id	2.3.8
cis_benchmark	CIS Microsoft Azure Compute Services Benchmark v2.0.0
tech_stack	["azure"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

Ensure end-to-end TLS encryption is enabled

Description

End-to-end (E2E) TLS encryption ensures that front-end to worker communication within function 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 CLI

Run the following command to list function apps:

az functionapp list

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

az functionapp show --resource-group <resource-group-name> --name <function-app-name> --query endToEndEncryptionEnabled

Ensure that the command returns true.

Using Azure Portal

There is no Azure Portal audit procedure documented for this control. Use the Azure CLI or Azure Policy methods.

Expected Result

The endToEndEncryptionEnabled setting should return true.

Remediation

Using Azure CLI

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

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

Using Azure Portal

There is no Azure Portal remediation procedure documented for this control. Use the Azure CLI method.

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/functionapp