Subject: Re: [Ace] Token (In)Security

From: Ludwig Seitz <[email-masked]>
Date: Fri, 11 Jan 2019 14:09:25 +0100

On 18/12/2018 15:48, Stefanie Gerdes wrote:
> Hi Hannes,
> 
> I think the text is much better now. Protecting the integrity of
> self-contained tokens is not sufficient, however. The RS must not only
> ascertain that the token is integrity-protected but also validate its
> authenticity, i.e., that it stems from an authorized AS.
> 
> Viele Grüße
> Steffi
> 

Hi,

I've merged Hannes' PR, fixed a typo and added a sentence as follows:
=====================================================================
For self-contained tokens the RS MUST process the security protection of 
the token first, as specified by the respective token format. ~snip~ 
This MUST include a verification that security protection (and thus the 
token) was generated by an AS that has the right to issue access tokens 
for this RS.
=====================================================================

I have not extended this requirement to tokens passed as a reference, 
since in that case the RS needs to do introspection at an authorized AS 
anyways. It would thus not get the claims of a token issued by an 
unauthorized AS, which would in turn lead to the token being discarded.

Does that sound correct to you all?

/Ludwig

-- 
Ludwig Seitz, PhD
Security Lab, RISE
Phone +46(0)70-349 92 51

---

From: Stefanie Gerdes <[email-masked]>
Date: Wed, 16 Jan 2019 11:15:54 +0100

Hi Ludwig,

That's better, thanks.

Viele Grüße
Steffi