Ensure Developer/Premium SKUs are in use for Azure API Management

Basic and other lower tiers of Azure API Management do not allow the use of Azure VNet. This may allow the clients to access your APIs directly. Thus increasing attack surface.

In Azure Console -

1. Open the Azure Portal and go to API Management.
2. Select the API Management service you wish to edit.
3. Select Pricing tier under Deployment + Infrastructure.
4. For Pricing tiers, choose the appropriate option.

In Terraform -

1. In the azurerm_api_management resource, set 'sku_name' to a value that starts with 'Developer_' or 'Premium_'.

References:
https://learn.microsoft.com/en-us/azure/api-management/
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/api_management#sku_name