IETF Logo Mail Archive

Re: [OAUTH-WG] Token Mediating and session Information Backend For Frontend (TMI BFF)

Neil Madden <neil.madden@forgerock.com> Mon, 15 February 2021 10:14 UTC

Return-Path: <neil.madden@forgerock.com>
X-Original-To: oauth@ietfa.amsl.com
Delivered-To: oauth@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id BB1BE3A0EF0 for <oauth@ietfa.amsl.com>; Mon, 15 Feb 2021 02:14:53 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.198
X-Spam-Level:
X-Spam-Status: No, score=-0.198 tagged_above=-999 required=5 tests=[DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=forgerock.com
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 KkbJdofjmfGL for <oauth@ietfa.amsl.com>; Mon, 15 Feb 2021 02:14:52 -0800 (PST)
Received: from mail-wm1-x334.google.com (mail-wm1-x334.google.com [IPv6:2a00:1450:4864:20::334]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 451013A0DC4 for <oauth@ietf.org>; Mon, 15 Feb 2021 02:14:52 -0800 (PST)
Received: by mail-wm1-x334.google.com with SMTP id r5so2459851wmp.1 for <oauth@ietf.org>; Mon, 15 Feb 2021 02:14:52 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=forgerock.com; s=google; h=from:mime-version:subject:date:message-id:references:cc:in-reply-to :to:content-transfer-encoding; bh=mZaRg1uWVMsP5sTOQyoGv6hReuRI7orsXvscT480asQ=; b=jpqbfB0IcKTTrRYvsKHO+R7nZlanwwQwO7NNZGjYCbHjcyWhOIMEHskkiVP81JItpQ LfTss2gQ3fy9175pw3bkcCNwZkUFhVPpfaoy5gsQC+ejOz2RCIekL0125lSHIYont4jQ LMHP97yBHLwmp6S7E2xNVdrwmfi6OyNwN1l0g=
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:mime-version:subject:date:message-id :references:cc:in-reply-to:to:content-transfer-encoding; bh=mZaRg1uWVMsP5sTOQyoGv6hReuRI7orsXvscT480asQ=; b=dkr6m/pYmayiZw/0iWitY6sqviaNSr+U+fPpKmJkeC5xqO+/af5XNZktJ36vaTGRYL oi+oHRsXFNmpCjgn2bsjN0iSYzn5bIuwYZosz/JjocFuZJ0D8y1V1uJKG2LL+ncMUkvc JSLzLmGH3CjMGH1RZUlj0cfD08+Lsrihgo2Sp36KKyh2tsKgHVrF8ccJFx8rQtiilF+8 UpIweZ+7gCMq7qeY5V9de77Q+I0uVRZE7rNU70pBz857Z2HRNfinPgsPp1wnjHu1D9zF yQLho45FGkM9lcWlPivZJ5+cRrpMyecSc8ZLdtW2aPsdQLtBPJH98c3YrzL4CeNVJ+Mt LiTg==
X-Gm-Message-State: AOAM530R79oBLv0lo505LJIAwqxN1PZUePpGZoyCthdoavMuIB/Zy1hc xhwU7kQMl2iURReRvw8XueMPxvyIA83cax2AHA9S4uDu7WJtdIsYCyd1yo3RzBl3/u6+gA8TQw= =
X-Google-Smtp-Source: ABdhPJx8yAQXXTw5IcauMfy3PSVWO+Ql7/X9QFt+Ny92+LqNzjHVixaPlTxyVVuemkZY2laqFmEzSQ==
X-Received: by 2002:a7b:c214:: with SMTP id x20mr10100161wmi.185.1613384090526; Mon, 15 Feb 2021 02:14:50 -0800 (PST)
Received: from [10.0.0.2] (252.207.159.143.dyn.plus.net. [143.159.207.252]) by smtp.gmail.com with ESMTPSA id t74sm17848526wmt.45.2021.02.15.02.14.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 15 Feb 2021 02:14:49 -0800 (PST)
From: Neil Madden <neil.madden@forgerock.com>
Mime-Version: 1.0 (1.0)
Date: Mon, 15 Feb 2021 10:14:47 +0000
Message-Id: <E0F02703-4B45-4466-8A00-DB55D49891B4@forgerock.com>
References: <43B559AA-D888-4E8D-8F82-4226676AC536@pragmaticwebsecurity.com>
Cc: Vittorio Bertocci <vittorio.bertocci@auth0.com>, oauth@ietf.org
In-Reply-To: <43B559AA-D888-4E8D-8F82-4226676AC536@pragmaticwebsecurity.com>
To: Philippe De Ryck <philippe@pragmaticwebsecurity.com>
X-Mailer: iPhone Mail (18C66)
Content-Type: multipart/alternative; boundary="Apple-Mail-5C230414-B64C-40D7-A7D8-806CC0015B08"
Content-Transfer-Encoding: 7bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/oauth/g-7ZW1NZVxmJdrHrjO3nDkQ_O6w>
Subject: Re: [OAUTH-WG] Token Mediating and session Information Backend For Frontend (TMI BFF)
X-BeenThere: oauth@ietf.org
X-Mailman-Version: 2.1.29
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: Mon, 15 Feb 2021 10:14:54 -0000


> On 15 Feb 2021, at 08:32, Philippe De Ryck <philippe@pragmaticwebsecurity.com> wrote:
> 
> [...]
> 
> Compared to using a worker for handling RTs, I believe the TMI-BFF only adds a single security benefit: an attacker is no longer able to run a silent flow to obtain a fresh set of tokens (since the client is now a confidential client). 

But they can just call the bff-token endpoint to do the same. If there is a security advantage, IMO it is as a defence in depth against open redirects, unicode normalisation attacks (ie not validating the redirect_uri correctly at the AS), etc. 

— Neil
-- 
ForgeRock values your Privacy <https://www.forgerock.com/your-privacy>

v2.23.0 | Report a Bug | By Email