Using Fiddler to trace a SAML IDP Request from ADFS 2.0

Introduction

Over the past couple of days I have been doing some diagnostics with a partner to setup SSO over a SAML HTTP POST using ADFS. The partner is using the SAML ComponentSpace component. An important part of the diagnostics has been collecting the HTTP POST trace and sending this to the partner for diagnostics. This post shows the steps I went through to trace the HTTP POST using Fiddler.

I saw one MSDN thread that mentioned a similar technique to mine but I wanted to document the steps here because it is not trivial or simple.

Walkthrough

This walkthrough assumes you have already downloaded Fiddler and have setup at least one relying party.

1. Configure IIS so that it can be used with Fiddler tracing and ADFS. See the following TechNet Wiki article for more information: http://social.technet.microsoft.com/wiki/contents/articles/ad-fs-2-0-continuously-prompted-for-credentials-while-using-fiddler-web-debugger.aspx?wa=wsignin1.0&CommentPosted=true. I did not do this step but I am presenting this here in case you run into the problem presented on the link. When authenticating, I checked the box to remember my password.
2. Configure Fiddler for processing HTTPS. Open the Fiddler options and check the boxes like shown below. Ignoring server certificate errors is optional:
3. Open the browser and navigate to https://adfsFQDN/adfs/ls/IdpInitiatedSignOn.aspx. This page will look like:
4. Choose to sign in. You will receive an authentication box, so authenticate with Windows credentials.
5. Then you will see a windows similar to the one below:
6. Before clicking Go, open Fiddler so that the trace will be collected.
7. Then click Go in the browser. The trace as collected in Fiddler will be collected like in the screenshot below (sorry this screenshot is a pretty large file but it shows a lot of important details):
8. You will want to find the last page that includes the “adfs/ls” in the list in the left window in Fiddler. Click on that one. Then on the right window choose to see it “Raw”.
9. Next you want to select all of the encoded blob from the RAW window but not all of the HTTP POST. You can select this blob and copy it.
10. Then click on the Encoder toolbar button, which gives you the ability to unencode the blob. The SAML POST will be Base64 encoded so you have to unencode it to get the unencoded trace. Choose the option “From Base64″ to see the unencoded Samlp response as shown below:

Thanks!