Active Directory – Send objectGUID as an AD FS 2.0 Claim

Well, since nobody did answer, i took the time, setup a test lab and sniffed the HTTPS traffic. Here are my research results in case anybody else will ever come across this thing:

• I still got no official source for this questions
• First off: yes, transitive trust is possible and there is no way to block it except of legal affairs. A propper SLA is the basis for any federation scenario anyways.
• There is no special "setting" to disable or enable it, but using the claims rule engine a trusted partner may configure ANY kind of outgoing claims IF ANY kind of incomming claims are detected, so there is no way to "protect" illegal access.
• In my tests, none of the rule templates that come with ADFS changed the OriginalIssuer property of the claims. One may think: Okay so i can use that property to verify the original source of any claim and build a filter to only allow claims comming directly from (and not traversed through, which by default only affects the Issuer but not the OriginalIssuer property) a trusted partner. But thats wrong, why? Look at the next line.
• As i said, the default templates don't touch the OriginalIssuer property. But you may create custom rules using the rule engine. Using that one, you can change pretty much every claim type, value and their properties. And yes: also the OriginalIssuer. So to the federation provider it looks as the claims are comming directy from the trusted partner, where in reality they're only transformed there.

So, what i would suggest to atleast minimize "transitive" scenarios if they're unwanted, is to check for the OriginalIssuer. It dosn't protect from transitive logins, but a admin would have to explicitly configure it - which would make legal affiars much more easier in a case of SLA voilation. Also, i'm not thinking of the possibility to change the OriginalIssuer as a "bug", in fact: even without that feature, every thrid party software could always make it able to act as a proxy between backend systems and the trusted identity provider. For example the IdP could create shadow accounts for partner (C) - so there will always be a workaround since when using federation, you're giving away the control on who is able to delegate access rights to specific ressources.

Anyway - if you have been as curious as i about how ADFS 2.0 handles transitive trusts, now you know without the need to build a testlab and sniff HTTPS traffic.

Is this lab just for your learning or for some proof of concept intended to be used in production later?

The token based agent approach you are trying to implement is the old school method introduced in 2003 R2. Are you sure you need to do it this way for production?

The current way of federating apps is to use WIF. See http://msdn.microsoft.com/en-us/library/hh987037(v=vs.110).aspx for a sample using the latest WIF version.

In that sample replacing the references to

• http://localhost:13922/wsFederationSTS/Issue with http://sts1.sub.domain.com/adfs/ls/ and
• http://localhost:28503/ with http://adfstest.sub.domain.com/ and
• 1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234 with your AD FS token signing cert hash as visible when running get-adfscertificate cmdlet on AD FS

Also see http://www.cloudidentity.com/blog/2014/02/12/use-the-on-premises-organizational-authentication-option-adfs-with-asp-net-in-visual-studio-2013/ for and to end example of using WIF and AD FS. That article shows AD FS on Windows Server 2012 R2 in use but is perfectly applicable here.