What’s the security implication of changing the default client type from confidential to public in Azure AD?

From time to time, I get asked this question by a few different customers especially when they encounter the error “AADSTS7000218: The request body must contain the following parameter: ‘client_assertion’ or ‘client_secret’” when authenticating to Azure AD. The error is related to the following Default client type setting in the Authentication blade of a registered application: By default the setting is set to No (confidential client). Changing to ‘Yes’ converts…

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Using OpenID Connect OWIN middleware to validate an Azure AD JWT token signed with a symmetric key

Azure AD by default uses a certificate to sign an OAuth2 JWT token using an asymmetric algorithm (RS256). Alternatively a JWT token can be signed with a “shared” secret using a symmetric algorithm (HS256). Asymmetric signing algorithm is always more secure in preventing the token to be tampered with compared to a symmetric algorithm since the private key is always kept at the Identity Provider (IDP) and the token consumer…

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Some tips and tricks with Fiddler capture

Recently, I came across a couple of scenarios where I could not get Fiddler to capture SSL traffic easily. Below are the some tips and tricks that may help in these situations. Scenario 1: Capture Node.js web traffic in Fiddler In the same command window where you run npm start to start the node server, run the below set commands first to set the proxy info before running npm start.…

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Getting Azure Key Vault secret with Azure.Identity and Azure.Security.KeyVault

In my last post, I talked about using ADAL (now deprecated) with the KeyVaultClient class to get an access token using OAuth2 Client Credentials Grant flow and query Azure Key Vault with that access token. In this post, I’ll talk about using a couple of new classes in the Azure SDK for .NET library to accomplish the same goal. We will use Azure.Identity name space for our Azure AD token…

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NetLog: Alternative to Fiddler and HAR captures

Have you run across where you can’t get a standard Fiddler capture, and furthermore, HAR captures from developer tools is truncating the information you need to see? I ran across the NetLog tool built into Chromium based browsers. So, this will work in the new Microsoft Edge, Chrome, and Electron. Here are couple known limitations before we get started… POST request bodies are not captured. Sites running in compatibility mode…

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Update Asp.Net or Asp.Net Core app session to last longer than Azure AD tokens

Azure AD tokens (ID tokens, access tokens, and SAML tokens) by default last one hour. Asp.Net and Asp.Net Core Middleware sets their authentication ticket to the expiration of these tokens by default. If you do not want your web application to kick the user out redirecting them to Azure AD to sign-in again, you can customize the Middleware authentication ticket. This can also help resolve AJAX issues (getting CORS error…

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Script errors running MSAL.Net in XBAP application

You may encounter script errors with the background text saying cookies are disabled when running MSAL code snippet similar to the following in a XAML Browser Application (XBAP) from Internet Explorer when performing Azure AD login Root Cause XBAP Applications, although housed in Internet Explorer, runs in its own process space: PresentationHost.exe, which is a very tightly-controlled security container. XBAP Application uses the webBrowser control to host the Azure AD…

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Azure Active Directory: How to get the signed in users groups when there is a groups overage claim in an Access token.

Azure AD has a maximum number of groups that can be returned in an access token when you have selected to include the groups claim for your access token. This post will show you how to reproduce the scenario and then how to get the users groups using Microsoft Graph when a groups overage claim is present in the token instead of actual groups. For a JWT token, Azure has…

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Microsoft Graph: Why you cannot call the “me” endpoint with a token acquired via the client credentials grant flow

Introduction Microsoft Graph has a couple of primary ways you can get information about a user in Azure AD. This not only includes things like the user attributes but also groups the user is a member of, access to mail, and etc. Each endpoint does require specific permissions but generally speaking, a user can get the basic information about him/herself via the “me” endpoint. The “me” endpoint From our docs…

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