Re: [secdir] [xmpp] SecDir review of draft-ietf-xmpp-3920bis-17

Kurt Zeilenga <Kurt.Zeilenga@Isode.COM> Tue, 02 November 2010 14:13 UTC

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From: Kurt Zeilenga <Kurt.Zeilenga@Isode.COM>
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Date: Tue, 2 Nov 2010 07:13:14 -0700
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Cc: Security Area Directorate <secdir@ietf.org>, The IESG <iesg@ietf.org>, XMPP Working Group <xmpp@ietf.org>, "draft-ietf-xmpp-3920bis.all@tools.ietf.org" <draft-ietf-xmpp-3920bis.all@tools.ietf.org>
Subject: Re: [secdir] [xmpp] SecDir review of draft-ietf-xmpp-3920bis-17
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On Nov 2, 2010, at 5:12 AM, Peter Saint-Andre wrote:

> On 11/2/10 5:20 AM, Yaron Sheffer wrote:
>> I'm OK with this text, including (sigh) PLAIN.
> 
> If it's any consolation, I'm sighing along with you. :)
> 
> Two points:
> 
> 1. Eventually, we should be able to drop PLAIN in a future revision of
> the MTI technologies spec that we'll pull out of 3920bis in 1+ years.

Good luck with that.  The arguments used now for its inclusion is likely to be repeated and, again, win.

Personally, I am against MUST'ing or SHOULD'ing TLS+PLAIN.  While it does offer good interoperability, it does good enough security for today's, and more importantly, tomorrow's Internet.

I think we actually should be mandating a SCRAM-*-PLUS mechanism, because channeling bindings are really needed due to 'user click through' of TLS warnings, downgrade attack warnings, etc..   I do suspect that it will take time for this mechanism to be come ubiquitous, but I fear that without a MUST, it will never become ubiquitous.   But I do suspect well have multiple independently developed implementations of SCRAM-*-PLUS in XMPP within a few months of publication of this revision of XMPP.

I suspect I'm in the rough on both points.  Oh well.

> 2. The technology that the XMPP community uses for account registration
> (XEP-0077) could benefit from an update, or even a replacement, and when
> that work is completed I'd like to include a method by which a client
> could register a key or cert with the server, thus smoothing the path
> toward password-less authentication. IMHO that will be the best approach
> in the longer term, instead of continually tweaking the password-based
> methods. But that's a topic for another time...

I also think transition-needed needs to be deprecated in favor of transition within the bound channel (e.g., today via XEP 77, tomorrow ?).

> 
> Peter
> 
> -- 
> Peter Saint-Andre
> https://stpeter.im/
> 
> 
> 
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