Re: [dispatch] DISPATCH IETF 111 meeting - preliminary outcomes and draft minutes

[Eric Rescorla <[e-mail]>]

On Wed, Jul 28, 2021 at 10:59 AM Richard Barnes <[e-mail]> wrote:

> On Wed, Jul 28, 2021 at 1:32 PM Eric Rescorla <[e-mail]> wrote:
>
>>
>>
>>> So if folks want to make a bigger, scarier warning label to put on SDES
>>> to guide people away from it, sure, fine.  But it doesn’t seem like a
>>> blaring red warning light is called for.  In terms of this document, the
>>> content is probably mostly OK if we reframe it in that light.  Obsoleting
>>> SDES and marking it Historic, though, is over the top; it will just create
>>> unnecessary consternation.
>>>
>>
>> I'm not really following your argument here. We all agree that (1) SDES
>> is bad (2) We have better alternatives in the form of DTLS-SRTP and
>> (eventually) MLS-SRTP. So, precisely what harm is it doing to tell people
>> that and that they shouldn't use SDES in favor of that. "consternation" is
>> not a real harm.
>>
>
> We agree with regard to the future.
>
> What are operators of existing systems using SDES supposed to take away
> from this?  This is not like say the SSLv3 deprecation where we had new
> data (POODLE) that changed the posture of these systems.  Systems based on
> SDES are as secure / insecure as they ever were.
>

What's changed is (1) a clearer appreciation of the threat model and (2)
more widespread availability of better technologies.


So what I'm worried about is (a) the IETF looking alarmist for marking a
> bunch of things insecure that are actually fine,
>

The point, as John has ably documented, is that they're not fine.


and (b) to the degree the deprecation is taken seriously, creating a bunch
> of work to upgrade from SDES to a flavor of DTLS-SRTP that is not enough
> better to merit the effort.
>

It seems to me that replacing SDES with DTLS-SRTP (or, I guess, MLS-SRTP)
is precisely the intended outcome here.

-Ekr




>
> --Richard
>
>
>
>>
>> -Ekr
>>
>>
>>> --Richard
>>>
>>> On Tue, Jul 27, 2021 at 7:08 PM John Mattsson <john.mattsson=
>>> [e-mail]> wrote:
>>>
>>>> westhawk [e-mail] wrote:
>>>>
>>>>
>>>>
>>>> >> On 26 Jul 2021, at 23:30, Kirsty P <Kirsty.p=[e-mail]> <&lt;Kirsty.p=[e-mail]&gt;> >wrote:
>>>>
>>>> >>
>>>>
>>>> >> SDP Security Descriptions is NOT RECOMMENDED and Historic: consensus was >sub-optimal. There was support for revisiting the space currently standardised >by SDP, but not on direction (whether to do a deprecation with/without >replacement). Future paths suggested included: mmusic, a new WG, more work >required for it to be ready, or a BoF (said in chat) to vet the idea further.
>>>>
>>>> >My sense is that there was a rough consensus around a goal to make it possible >to deprecate SDES - but the required steps were unclear.
>>>>
>>>>
>>>>
>>>> Yes, looking at the Jabber log there was quite strong support for the
>>>> goal of deprecating SDES:
>>>>
>>>>
>>>>
>>>> Eric Rescorla: Let's all just agree that this (Mattson's SDES) draft is
>>>> a good idea and promote it to full standard toda
>>>> Martin Thomson: now that I see John presenting this, I have to wonder:
>>>> why didn't this deprecation happen before?
>>>> Sean Turner: When Dan Wing got up and said not to use SDES in Berlin -
>>>> I assumed that was that ;)
>>>> Pete Resnick: Why "NOT RECOMMENDED" instead of "MUST NOT"?
>>>> Sean Turner: +1 to what ekr said
>>>> Rich Salz: +1 also
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Regarding the next required steps I agree with Pete. Let’s charter.
>>>>
>>>>
>>>>
>>>> Ben Kaduk: So is this dispatch to BoF, or straight to WG?
>>>>
>>>> Pete Resnick: @ben: Sounds like this discussion has done the
>>>> equivalent of BoFing. Charter.
>>>>
>>>>
>>>>
>>>> Cheers,
>>>>
>>>> John
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>>