Re: [OAUTH-WG] Fixing the Authorization Server Mix-Up: Call for Adoption

Mike Jones <> Fri, 19 February 2016 20:19 UTC

Return-Path: <>
Received: from localhost ( []) by (Postfix) with ESMTP id 2F3B61B2D82 for <>; Fri, 19 Feb 2016 12:19:19 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2.001
X-Spam-Status: No, score=-2.001 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001] autolearn=ham
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id kIX9HLumvQyE for <>; Fri, 19 Feb 2016 12:19:15 -0800 (PST)
Received: from ( [IPv6:2a01:111:f400:fc10::721]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 2C2AE1B2A7A for <>; Fri, 19 Feb 2016 12:19:15 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=selector1; h=From:To:Date:Subject:Message-ID:Content-Type:MIME-Version; bh=iXKzrUrjG8ZD6H3Oz2m/bLq1vUqElz2yittqpsAubj0=; b=jycKl6de36L1SoPjEX2Mp9cP6QHaB+7gtlV2+0XZYT1vZOhRuiPhXnCYGnugxdNwu5cIYJxXfw+QNEZW438uZv6JRN2N24maC3F9GhXVF4QJyigcMUQNdxQHH2wjCv1YAODr7SekWVq8aoXtncFHiR7aAoY/EPCE+agrLKYub2c=
Received: from ( by ( with Microsoft SMTP Server (TLS) id 15.1.409.15; Fri, 19 Feb 2016 20:18:55 +0000
Received: from ([]) by ([]) with mapi id 15.01.0409.017; Fri, 19 Feb 2016 20:18:55 +0000
From: Mike Jones <>
To: Hannes Tschofenig <>, "" <>
Thread-Topic: [OAUTH-WG] Fixing the Authorization Server Mix-Up: Call for Adoption
Thread-Index: AQHRa02vcYDFrUX6M06+JVJIk0JwsZ8zyRTA
Date: Fri, 19 Feb 2016 20:18:55 +0000
Message-ID: <>
References: <>
In-Reply-To: <>
Accept-Language: en-US
Content-Language: en-US
authentication-results:; dkim=none (message not signed) header.d=none;; dmarc=none action=none;
x-originating-ip: []
x-ms-office365-filtering-correlation-id: 31b81990-ce68-4aba-8701-08d33969e450
x-microsoft-exchange-diagnostics: 1; BY2PR03MB442; 5:xwrFzgZ99SoZrrcrLrXdDOhwrJ2xdjAWWrpc/mW0rC7x5fwOyHmtdKOb88rhKndVNSWK3SCRJ534yyuXIECmvYmuLPJEVEUnu9lZFoiBozwcOW8bNdpOD29aysJNcSjaXmecPM6qZKV3CXh4BcGYKg==; 24:5y+0ku8wMBWMGqCNQ/ExAp2ypC2h93FIO4g++StXb1FCoGMBPC71XT6t4K2up6CwglQrhuC+Q70O46bHuzxupu68e8Dcozhsw/w+R44E8Mo=
x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:BY2PR03MB442;
x-microsoft-antispam-prvs: <>
x-exchange-antispam-report-test: UriScan:;
x-exchange-antispam-report-cfa-test: BCL:0; PCL:0; RULEID:(61425038)(601004)(2401047)(8121501046)(5005006)(3002001)(10201501046)(61426038)(61427038); SRVR:BY2PR03MB442; BCL:0; PCL:0; RULEID:; SRVR:BY2PR03MB442;
x-forefront-prvs: 08572BD77F
x-forefront-antispam-report: SFV:NSPM; SFS:(10019020)(72854002)(13464003)(377454003)(86362001)(19580405001)(5001960100002)(86612001)(19617315012)(586003)(3660700001)(790700001)(1220700001)(87936001)(2900100001)(2501003)(15975445007)(77096005)(5001770100001)(19580395003)(1096002)(102836003)(2950100001)(6116002)(189998001)(92566002)(107886002)(3846002)(54356999)(5003600100002)(5004730100002)(11100500001)(99286002)(16236675004)(33656002)(5008740100001)(10090500001)(5002640100001)(66066001)(50986999)(76576001)(5005710100001)(122556002)(10400500002)(3280700002)(106116001)(2906002)(19300405004)(10290500002)(40100003)(76176999)(19625215002)(74316001)(15940465004); DIR:OUT; SFP:1102; SCL:1; SRVR:BY2PR03MB442;; FPR:; SPF:None; MLV:sfv; LANG:en;
spamdiagnosticoutput: 1:23
spamdiagnosticmetadata: NSPM
Content-Type: multipart/alternative; boundary="_000_BY2PR03MB442E9BF84AFA890378C5116F5A00BY2PR03MB442namprd_"
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-originalarrivaltime: 19 Feb 2016 20:18:55.1860 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY2PR03MB442
Archived-At: <>
Subject: Re: [OAUTH-WG] Fixing the Authorization Server Mix-Up: Call for Adoption
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: OAUTH WG <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Fri, 19 Feb 2016 20:19:19 -0000

Option A.  I have higher confidence that this specification solves the problems because it was designed during a 4-day security meeting dedicated to this task by a group of over 20 OAuth security experts, including both sets of researchers in Germany who originally identified the problem.  This solution has also been implemented and interop tested by Roland Hedberg, Brian Campbell, and I believe others.  Note that the reason I am advocating this specification is *not* because I'm an editor of it; my role was to record in spec language what the OAuth security experts designed together over the 4-day period in Darmstadt.

I’ll also note that even if Option B also solves the problem, it comes at significant adoption costs and complexity not found in A.  In particular, it requires that developers understand support a new “Link Relation” syntax not used elsewhere in OAuth.  As Nat writes about his own draft in - there is not a standard JSON syntax for link relations.  He writes “we could easily create a parallel to it”.  I’d rather we solve the problem using standard mechanisms already employed in OAuth, rather than risk bifurcating OAuth in the developer community by unnecessarily inventing/creating new syntax that is unfamiliar to developers and that many of them may reject using.

                                                          -- Mike

P.S.  Information about the OAuth security meeting can be found at and .

-----Original Message-----
From: OAuth [] On Behalf Of Hannes Tschofenig
Sent: Friday, February 19, 2016 11:43 AM
Subject: [OAUTH-WG] Fixing the Authorization Server Mix-Up: Call for Adoption

Early February I posted a mail to the list to make progress on the solution to the OAuth Authorization Server Mix-Up problem discovered late last year.

Here is my mail about the Authorization Server Mix-Up:

Here is my mail to the list that tries to summarize the discussion status and asked a few questions:

Unfortunately, my mail didn't lead to the intended success. While there was some feedback I wasn't getting the desired response.

In order to move forward I believe we need a working group document that serves as a starting point for further work in the group*. We have two documents that provide similar functionality in an attempt to solve the Authorization Server Mix-Up problem.

So, here is the question for the group. Which document do you want as a starting point for work on this topic:

-- Option A: 'OAuth 2.0 Mix-Up Mitigation' by Mike Jones and John Bradley


-- Option B: 'OAuth Response Metadata' by Nat Sakimura, Nov Matake and Sascha Preibisch


Deadline for feedback is March, 4th.


Hannes & Derek

PS: (*) Regardless of the selected solution we will provide proper acknowledgement for those who contributed to the work.