Re: [SECMECH] Framework Bindings Vs. Mechanism Bridges

Bernard Aboba <aboba@internaut.com> Thu, 25 August 2005 03:52 UTC

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Date: Wed, 24 Aug 2005 19:03:21 -0700 (PDT)
From: Bernard Aboba <aboba@internaut.com>
To: Charles Clancy <clancy@cs.umd.edu>
Subject: Re: [SECMECH] Framework Bindings Vs. Mechanism Bridges
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> Why would the cleartext password ever end up on a NAS?

If the NAS terminates the TTLS tunnel, and PAP is negotiated within TTLS 
this can happen. 

> Maybe a picture would help:
> 
> EAP Client          EAP Server           KDC
> --------------------------------------------
> 
>     TTLS Negotiation
> <----------------------->
> 
> krb5 authentication (EAP server is passthrough)
> <------------------------------------------>

Is the assumption here that an EAP-Kerberos method is run within the TTLS 
tunnel, thereby protecting the Kerberos exchange?  If so, then this mode 
of interaction protects the Kerberos exchange from dictionary attack. 


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