Re: [SECMECH] Framework Bindings Vs. Mechanism Bridges

Nicolas Williams <Nicolas.Williams@sun.com> Fri, 19 August 2005 18:05 UTC

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Date: Fri, 19 Aug 2005 13:05:40 -0500
From: Nicolas Williams <Nicolas.Williams@sun.com>
To: "Salowey, Joe" <jsalowey@cisco.com>
Subject: Re: [SECMECH] Framework Bindings Vs. Mechanism Bridges
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On Fri, Aug 19, 2005 at 10:31:51AM -0700, Salowey, Joe wrote:
>  
> > From: Nicolas Williams [mailto:Nicolas.Williams@sun.com] 
> > On Wed, Aug 17, 2005 at 06:14:07PM -0400, Charles Clancy wrote:
> > > Mechanism Bridges sounds like a hack to me.
> > > 
> > > IMHO, Framework Bindings sounds like the way to go.  It 
> > gives you more 
> > > control over which mechanisms are used in which frameworks.  Each 
> > > framework has a different threat model, and not all mechanisms from 
> > > one framework may be good in another.  For example, using 
> > basic krb5 
> > > in 802.11i-EAP is a bad idea because of dictionary attacks.
> > 
> > Sure, but you could always do 
> > krb5-over-TLS-with-cryptographic-bindings.
> >
> 
> [Joe] How would this be instantiated?  

Aren't there EAP methods for tunnelling over TLS?

Also, Kerberos V w/ PKINIT addresses the dictionary attacks issue as
well; I should have mentioned that earlier.

(Kerberos V pre-auth is extensible; the dictionary attacks on password
pre-auth issue is specific to one type of Kerberos V pre-auth, the one
standard type, of course, but PKINIT is another type.)

>                                        Currently EAP does not run over a
> specific security layer.  There are EAP mechanisms that provide a secure
> tunnel for running other mechanisms.

That's what I was referring to.  Aren't these mechanisms there precisely
to provide protection to other mechanisms that otherwise would be unsafe
to use?

>                                       Would an EAP to GSS bridge have to
> be a tunneling method?

No.  But if some mechanism for which a bridge is being used requires
additional protection then tunnelling it over TLS or what have you would
be important.

Nico
-- 

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