How to: Password Protect Azure App service - azure

Question

I have website that is Hosted in a Azure App Service. are there any options in azure so that I can put a password on the website. Ideally without changing the websites code.
Just a basic password or user name and password, doesn't need to be google or facebook login or AD login.
It is a .net based website and I have seen a few options to do this, but it means I have to change the code of the website in someway or another.
Surely with all that sophisticated cloud technology, I can go in to the portal and set a password at a server level? - Or is the only way to make some kind of change to the application?

Answer 1

It is possible to enable Basic Authentication for Azure Web Apps with some settings in the applicationHost.xdt. You can load some modules in this file on the start of your Web App.
Steps:
Navigate to your WebApp in the Azure Portal
In the left menu, search for the header Development Tools an select Advanced Tools (Kudu)
Use the Debug Console > CMD tool, to navigate to the WebApp directory: \home\site
Create a file named: applicationHost.xdt
Paste the following:
<?xml version="1.0"?>
<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform">
<location path="%XDT_SITENAME%" xdt:Locator="Match(path)">
<system.webServer>
<rewrite xdt:Transform="InsertIfMissing">
<allowedServerVariables xdt:Transform="InsertIfMissing">
<add name="RESPONSE_WWW_AUTHENTICATE" xdt:Locator="Match(name)" xdt:Transform="InsertIfMissing" />
</allowedServerVariables>
<rules xdt:Transform="InsertIfMissing">
<rule name="BasicAuthentication" stopProcessing="true" xdt:Transform="InsertIfMissing" xdt:Locator="Match(name)">
<match url=".*" />
<conditions>
<add input="{HTTP_AUTHORIZATION}" pattern="^Basic dXNlcjpwYXNzd29yZA==" ignoreCase="false" negate="true" />
</conditions>
<action type="CustomResponse" statusCode="401" statusReason="Unauthorized" statusDescription="Unauthorized" />
<serverVariables>
<set name="RESPONSE_WWW_AUTHENTICATE" value="Basic realm=Project" />
</serverVariables>
</rule>
</rules>
</rewrite>
</system.webServer>
</location>
</configuration>
Change the Basic Auth to your liking (default in example is: user:password)
Make sure the web.config rewrite rules don't contain <clear /> as this wil remove the effects from the applicationHost.xdt file
Save the file and Stop and Start your WebApp (a simple Restart will not suffice)
Notes:
Not sure if this works on Linux based WebApps..
You can add this step to you're deployment pipelines by using FTP
Update: I've noticed issues with applicationHost.xdt while using it on secondary Web App slots. Only the primary slot seems to work.
PS: Cross-post from my answer here.

Answer 2

You can use Authentication and authorization in Azure App Service.
Authentication/Authorization was previously known as Easy Auth.
Azure App Service provides built-in authentication and authorization support, so you can sign in users and access data by writing minimal or no code in your web app, RESTful API, and mobile back end, and also Azure Functions. This article describes how App Service helps simplify authentication and authorization for your app.
Source: Authentication and authorization in Azure App Service and Azure Functions.
EDIT:
The above is a solution to have a password protected App Service without changing any code whatsoever. At this point there is no alternative, as you can see in the open feedback issue Allow HTTP Basic authentication on basic apps
Hi everyone, we understand the demand for this feature, but we do not plan to support authentication at this level. We suggest using EasyAuth for this scenario.
https://learn.microsoft.com/en-us/azure/app-service/overview-authentication-authorization
EDIT 2:
This method forces the user to use google or facebook, etc...
This is not true. You can also create a user in your Azure Active Directory and use that one with Easy Auth. The username would be something like username#<YOUR-TENANT>.onmicrosoft.com