We have an App Service running in Azure that hosts a website. We've recently had a security review on the web site and one of the items found was that the end point below was exposed.
https://<appName>.azurewebsites.net:8172/msdeploy.axd
The recommendation is that this end point should be blocked and using a whitelist to allow limited access (e.g. the build machine that deploys to Azure). How do I block this end point?
After discussions with Microsoft support it appears that port 8172 is enabled for backwards compatibility with old versions of MsDeploy. This port is being phased out and will be open sometimes and not other times.
The fix was for us to create a new resource group, app service plan and app services multiple times until we ended up a server that had the port closed. This was frustrating but ultimately it did resolve the issue.
You could use IP level limitation in the Azure App Service access restrictions to allow limited IP addresses or VNet access to your app service. In this case, it will work on all the applications in your app service.
For some specific endpoint access control, perhaps, you need to control it with access authorization in your application code. Read Tutorial: Authenticate and authorize users end-to-end in Azure App Service and Managing access to apps.
Alternatively, you select to use Application Gateway integration with service endpoints. In this case, you only want the front end to be accessible to your end-users. The back-end should be locked down so it is only callable from the front-end. Also the front end subnet support NSG, you could restrict the end-users with IP and port to access your front end, meanwhile, it will limit access to your endpoint. See Securing Back-end App Service Web Apps with VNets and Service Endpoints for more details.
Hope this helps you.
