Re: [rtcweb] Security Architecture: SDES support is a MUST

Eric Rescorla <ekr@rtfm.com> Fri, 20 July 2012 13:50 UTC

Return-Path: <ekr@rtfm.com>
X-Original-To: rtcweb@ietfa.amsl.com
Delivered-To: rtcweb@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 3E9F521F85F0 for <rtcweb@ietfa.amsl.com>; Fri, 20 Jul 2012 06:50:13 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -102.843
X-Spam-Level:
X-Spam-Status: No, score=-102.843 tagged_above=-999 required=5 tests=[AWL=0.134, BAYES_00=-2.599, FM_FORGED_GMAIL=0.622, RCVD_IN_DNSWL_LOW=-1, USER_IN_WHITELIST=-100]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 9AZ158CXUDNW for <rtcweb@ietfa.amsl.com>; Fri, 20 Jul 2012 06:50:12 -0700 (PDT)
Received: from mail-vc0-f172.google.com (mail-vc0-f172.google.com [209.85.220.172]) by ietfa.amsl.com (Postfix) with ESMTP id 7558521F85EA for <rtcweb@ietf.org>; Fri, 20 Jul 2012 06:50:12 -0700 (PDT)
Received: by vcbfo14 with SMTP id fo14so3220121vcb.31 for <rtcweb@ietf.org>; Fri, 20 Jul 2012 06:51:08 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:x-originating-ip:in-reply-to:references:from:date :message-id:subject:to:cc:content-type:x-gm-message-state; bh=7eFx1JeM3EDcUHz/qIbFizUtN1VpxiQP4PKK6EK7v5s=; b=PGgutAfZv8/c2ckneTqcPWXAf9w/EzBqMoOVfUmLsiz4wHxV9DZm81lMurYUod7RJg us/dBQEhm+ytOHN4GK7tjP7JBfAMnm7DIon9zQ+zugXO0GpRBh1WGk+CoiyUHJ+yH5Tg wb9jqNdp+NWeV+TvGDMjQ+ywICqXH/P6vrIYi7CNXnpVdBNC3yYyyTIdrliJ9IKlisuH KVqQwph/wO8aP9Xih1l4giIUcJzyZW7VCJoUJt4YAypl+nOOYb0bfkApLEwOIXxm0tyz 3x3cIBm82JCzRlRl9UekWxkMqVnZKAJfihZZeQaJvhRT7dAe7O/QsGsVkxKH29BIT9md hD0Q==
Received: by 10.52.88.170 with SMTP id bh10mr3916046vdb.11.1342792268163; Fri, 20 Jul 2012 06:51:08 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.52.35.209 with HTTP; Fri, 20 Jul 2012 06:50:28 -0700 (PDT)
X-Originating-IP: [74.95.2.173]
In-Reply-To: <50095CE7.6030202@alvestrand.no>
References: <201207190742.q6J7glf6008744@vivaldi29.register.it> <500834FE.5040809@alcatel-lucent.com> <500835E1.2070502@infosecurity.ch> <50084717.7060301@alcatel-lucent.com> <BLU169-DS1488EF1F32A1EB2027582093D90@phx.gbl> <5008F7B9.7020804@infosecurity.ch> <500957ED.90807@alvestrand.no> <50095AAC.7030104@infosecurity.ch> <50095CE7.6030202@alvestrand.no>
From: Eric Rescorla <ekr@rtfm.com>
Date: Fri, 20 Jul 2012 06:50:28 -0700
Message-ID: <CABcZeBM4BwtUyr=MTft0SXSwhUO0vczWd0jOVUO=ea2SYiEcZA@mail.gmail.com>
To: Harald Alvestrand <harald@alvestrand.no>
Content-Type: text/plain; charset="ISO-8859-1"
X-Gm-Message-State: ALoCoQl+p67FKT5mOHMDnuTq/sqYEvLLF8w3qUD4SqDiup/AXfPQyUWu6gNv7keukB+Q3tgBS8NA
Cc: rtcweb@ietf.org
Subject: Re: [rtcweb] Security Architecture: SDES support is a MUST
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <rtcweb.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/rtcweb>
List-Post: <mailto:rtcweb@ietf.org>
List-Help: <mailto:rtcweb-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 20 Jul 2012 13:50:13 -0000

The draft currently states:

     *  The "security characteristics" MUST include some mechanism to
         allow an out-of-band verification of the peer, such as a
         certificate fingerprint or an SAS.

I'd be happy to have us specify a particular fingerprint algorithm (presumably
SHA-256, potentially truncated) but I haven't seen any evidence that
users savvy enough to inspect the fingerprint at all can't navigate more
than one hash. For example, Chrome's SSL/TLS inspector currently displays
MD5 and SHA-1. So I'm not sure something needs to be standardized here.

-Ekr


On Fri, Jul 20, 2012 at 6:28 AM, Harald Alvestrand <harald@alvestrand.no> wrote:
> On 07/20/2012 03:18 PM, Fabio Pietrosanti (naif) wrote:
>>
>> On 7/20/12 3:06 PM, Harald Alvestrand wrote:
>>>>
>>>> Current security definition of WebRTC does not support end-to-end
>>>> security.
>>>
>>> The current security definition of WebRTC (with DTLS) provides
>>> fingerprints.
>>> If the application is able to verify those fingerprints, security is end
>>> to end; if it isn't - it isn't.
>>
>> The security specification already does specify how the fingerprint must
>> be checked, against a third party system that must be trusted (unless
>> there is some recent update i didn't still checked).
>>
>> The way the specification describe fingerprint must be checked, does not
>> enforce end-to-end security but always rely on trusted third party,
>> being IdP (identity providers).
>>
>> The only way to achieve end-to-end security is not to have any kind of
>> trusted third party, as has been already discussed on
>> http://www.ietf.org/mail-archive/web/rtcweb/current/msg04043.html .
>
> That link is your request to have SAS considered mandatory.
>
> I believe you got some support for that proposal, or at least some kind of
> availability of digest information that can be verified independently, but I
> do not believe that you got any support for having SAS be the one and only
> definition of "end to end security".
>
> Thus, you may get support for your real request, but not for the language
> you use to describe it.
>
>>
>> Until WebRTC security architecture specification does not clearly define
>> a peer-to-peer fingerprint verification system that does not rely on
>> trusted third party it cannot be considered to provide end-to-end
>> security.
>>
>> Fabio
>> _______________________________________________
>> rtcweb mailing list
>> rtcweb@ietf.org
>> https://www.ietf.org/mailman/listinfo/rtcweb
>
>
> _______________________________________________
> rtcweb mailing list
> rtcweb@ietf.org
> https://www.ietf.org/mailman/listinfo/rtcweb