Azure App Service Security

Implementation of Azure App Service security features.

Create the infrastructure:

terraform init
terraform apply -auto-approve

Next, approve the Private Endpoint created by Front Door on behalf of App Service.

Access Restriction

Controls inbound connectivity. Functionality available when Public Access is set to TRUE.

Access can be controlled to the main site and the SCM (Advanced). Advanced can inherit rules from main.

This Terraform configuration will set up automatically ALLOW for:

• Service Tag: AzureFrontDoor.Backend
• HTTP Header: X-Azure-FDID

Do set Deny as the unmatched rule:

az resource update --resource-group rg-bigfactory --name app-bigfactory --resource-type "Microsoft.Web/sites" \
    --set properties.siteConfig.ipSecurityRestrictionsDefaultAction=Deny

Service Endpoints

It is possible to use the Azure backbone to access an App Service from a VM or other services.

This Terraform project automatically configures Microsoft.Web service endpoints for the VM subnet. Running Network Watcher will give the "next hop type" VirtualNetworkServiceEndpoint.

When removing the service endpoint, the next hop type will be Internet.

Private Endpoints

Couple of benefits:

• Avoid public endpoints
• Minimize the possibility of data exfiltration
• On-premises

Set create_private_endpoint_flag to true to enable the private endpoint:

create_private_endpoint_flag = true

Front Door latency benchmark

This project will create three apps to measure differences in latency:

• App 1 - AFD route with public endpoint.
• App 2 - AFD route with private endpoint.
• App 3 - No AFD, direct connection to the public endpoint.

export acr="crbigfactory"

Build and push the custom application:

cd app
bash acr-build-push.bash

Back to the root directory, change the configuration to pull from ACR:

webapp_deploy_from_acr = true

Apply:

terraform apply -auto-approve

Test the routes and measure the latency.

Virtual Network Integration

Only one VNET injection is supported.

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Clean-up

Once done, delete the resources:

terraform destroy -auto-approve