title: Azure AD - custom validation in external api
body: <p>I have 3 applications, one is desktop application and this is my client, second is my Web Api to secure and the last one is api which checks if the user with password exists.</p>
  
  <p>In my case I want to connect this flow with Azure AD.</p>
  
  <p>I think this should work like this:
  1.DesktopApplication sending request with clientid,clientsecret, username and password to AZURE
  2.Azure sending request with username and password to my api where I can check this user exist if exist I will return "true"(or somthing like this)
  3. If api return "true" Azure can return to DesktopApplication token
  4. DoesktopApplication will send request ot secure Web Api with token
  5.DesktopApplication recive content from secure Web Api</p>
  
  <p>Api in 3 point is not same api in 5 point.</p>
  
  <p>Is it posible to do this flow with Azure AD or not? And if not can I do something with my flow something to secure Web Api by Azure and still store users in my old db(oracle)?</p>