Re: [OAUTH-WG] Second OAuth 2.0 Mix-Up Mitigation Draft

Torsten Lodderstedt <torsten@lodderstedt.net> Tue, 26 January 2016 20:10 UTC

Return-Path: <torsten@lodderstedt.net>
X-Original-To: oauth@ietfa.amsl.com
Delivered-To: oauth@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id DEF621A00CA for <oauth@ietfa.amsl.com>; Tue, 26 Jan 2016 12:10:27 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.251
X-Spam-Level:
X-Spam-Status: No, score=-2.251 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HELO_EQ_DE=0.35, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001] autolearn=ham
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id fxgfmWl-CSFE for <oauth@ietfa.amsl.com>; Tue, 26 Jan 2016 12:10:22 -0800 (PST)
Received: from smtprelay04.ispgateway.de (smtprelay04.ispgateway.de [80.67.31.38]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 10F461B2C5B for <oauth@ietf.org>; Tue, 26 Jan 2016 12:10:22 -0800 (PST)
Received: from [79.218.87.147] (helo=[192.168.71.102]) by smtprelay04.ispgateway.de with esmtpsa (TLSv1.2:DHE-RSA-AES128-SHA:128) (Exim 4.84) (envelope-from <torsten@lodderstedt.net>) id 1aO9wP-0003Jm-Cq; Tue, 26 Jan 2016 21:10:17 +0100
To: Mike Jones <Michael.Jones@microsoft.com>, "oauth@ietf.org" <oauth@ietf.org>
References: <BY2PR03MB442662C73E3904E73D9B9EFF5C30@BY2PR03MB442.namprd03.prod.outlook.com>
From: Torsten Lodderstedt <torsten@lodderstedt.net>
Message-ID: <56A7D29F.2080701@lodderstedt.net>
Date: Tue, 26 Jan 2016 21:10:07 +0100
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1
MIME-Version: 1.0
In-Reply-To: <BY2PR03MB442662C73E3904E73D9B9EFF5C30@BY2PR03MB442.namprd03.prod.outlook.com>
Content-Type: multipart/alternative; boundary="------------070202000207060400050100"
X-Df-Sender: dG9yc3RlbkBsb2RkZXJzdGVkdC5uZXQ=
Archived-At: <http://mailarchive.ietf.org/arch/msg/oauth/1-jYvN0SYXMB0Ow1xmZmir7vNS8>
Subject: Re: [OAUTH-WG] Second OAuth 2.0 Mix-Up Mitigation Draft
X-BeenThere: oauth@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: OAUTH WG <oauth.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/oauth>, <mailto:oauth-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/oauth/>
List-Post: <mailto:oauth@ietf.org>
List-Help: <mailto:oauth-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/oauth>, <mailto:oauth-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 26 Jan 2016 20:10:28 -0000

Hi Mike,

I really like the new revision since it is much simpler :-)

My comments:

I'm fine with describing all mitigations we talked about in Darmstadt in 
one/this spec. But the state check at the tokens endpoint is supposed to 
be a mitigation against code injection/cut and paste attack, which is 
not directly related to IDP/AS mix up. So I would suggest to change the 
name of the spec, probably "OAuth security extensions"?

I think the code injection/cut and paste attack should be described more 
extensively in the introduction. It's important for the reader to 
understand, why this mitigation is defined at all. Moreover, I think the 
description of the mitigation is still incomplete/spread over the 
document. In order to detect code injection, the RP not only needs to 
send the state to the tokens endpoint, it also needs to (directly or 
indirectly) _bind_ the state to the particular user agent (session). 
Otherwise, the attacker can inject the state along with the solen code 
easily. I would suggest to merge

          "To prevent replay of the state in another browser instance by 
an attacker, the state value MUST be tied to the browser instance in a 
way that cannot be forged by an attacker. Section 4 of 
[I‑D.bradley‑oauth‑jwt‑encoded‑state]
          provides several examples of how a client can accomplish this."

into section 5.

I thought we had discussed to also give implementors a guideline on 
using state to prevent CSRF as well? How will we take care of that topic?

kinds regards,
Torsten.


Am 21.01.2016 um 07:28 schrieb Mike Jones:
>
> John Bradley and I collaborated to create the second OAuth 2.0 Mix-Up 
> Mitigation draft.  Changes were:
>
> ·Simplified by no longer specifying the signed JWT method for 
> returning the mitigation information.
>
> ·Simplified by no longer depending upon publication of a discovery 
> metadata document.
>
> ·Added the “state” token request parameter.
>
> ·Added examples.
>
> ·Added John Bradley as an editor.
>
> The specification is available at:
>
> ·http://tools.ietf.org/html/draft-jones-oauth-mix-up-mitigation-01
>
> An HTML-formatted version is also available at:
>
> ·http://self-issued.info/docs/draft-jones-oauth-mix-up-mitigation-01.html
>
> -- Mike
>
> P.S.  This note was also posted athttp://self-issued.info/?p=1526 and 
> as @selfissued <https://twitter.com/selfissued>;.
>
>
>
> _______________________________________________
> OAuth mailing list
> OAuth@ietf.org
> https://www.ietf.org/mailman/listinfo/oauth