Subject: [abfab] Heads Up: Significant Attack Against Deployments of EAP Channel Binding

From: Sam Hartman <[email-masked]>
Date: Mon, 05 Mar 2012 18:39:26 -0500

Hi.
While working on the Moonshot Implementation of EAP Channel Bindings,
Margaret Wasserman discovered some attacks. We've been working on
refining these attacks and put together a draft with our
analysis. Please see draft-hartman-emu-mutual-crypto-bind

This is not a protocol flaw in EAP Channel Bindings or the ABFAb core
specs.
However, it is a serious concern in adding EAP Channel Binding to
existing EAP methods.
so, it's something that we should cover in describing how EAP should be
used for application authentication.

This isn't a show stopper for Moonshot. The Moonshot Project can work
around this for its implementation. Similarly, I believe that enough
certificate validation will avoid this issue for people using ABFAB with
PLASMA.

However, this is a fairly serious issue for the EAP community as a
whole. It's very easy to deploy things in a manner where channel
bindings don't provide security.  We think the ABFAB community should
track this issue.  we'd ask that discussion take place on the
[email-masked] list.

Thanks for your consideration,

--Sam

---

From: Leif Johansson <[email-masked]>
Date: Tue, 06 Mar 2012 08:44:54 +0100

On 03/06/2012 12:39 AM, Sam Hartman wrote:
> 
> Hi. While working on the Moonshot Implementation of EAP Channel
> Bindings, Margaret Wasserman discovered some attacks. We've been
> working on refining these attacks and put together a draft with
> our analysis. Please see draft-hartman-emu-mutual-crypto-bind
> 

Do you want a slot to give an overview of the issue at the ABFAB
WG meeting?

	Cheers Leif

---

From: Sam Hartman <[email-masked]>
Date: Tue, 06 Mar 2012 08:19:53 -0500

>>>>> "Leif" == Leif Johansson <[email-masked]> writes:

    Leif> WG meeting?

I'm not sure that's necessary.
I think we'll be discussing at EMU.
I'm happy to take some open mic time if we have any.

If you want me to spend more I'm happy to do it, I just hope we'll be
busy with other things.

---

From: Sam Hartman <[email-masked]>
Date: Tue, 06 Mar 2012 08:22:18 -0500

Hmm.
Thinking more.
We'll obviously eventually have to discuss what we want to recommend for
abfab-like uses in response to that.
I think that will take time on the list and possibly in-person.

I'm definitely not ready for that now and  am not sure I'll be ready by
Paris with my own thoughts.
So, yes there are ABFAb aspects we'll have to consider.
Right now though I'm not ready to do more than give people a heads up.
Your call about whether to spend time.

--Sam

---

From: Leif Johansson <[email-masked]>
Date: Tue, 06 Mar 2012 14:38:40 +0100

On 03/06/2012 02:19 PM, Sam Hartman wrote:
>>> Bindings, Margaret Wasserman discovered some attacks. We've
>>> been working on refining these attacks and put together a draft
>>> with our analysis. Please see
>>> draft-hartman-emu-mutual-crypto-bind
>>> 
> 
> I'm not sure that's necessary. I think we'll be discussing at EMU. 
> If you want me to spend more I'm happy to do it, I just hope we'll
> be busy with other things.

Very good.