Re: [secdir] Secdir review of draft-hollenbeck-rfc4930bis-02

["Hollenbeck, Scott" <[e-mail]>]

Doesn't TLS provide protections for this issue?

-Scott-

 -----Original Message-----
From: 	Sandy Murphy [mailto:[e-mail]]
Sent:	Tuesday, July 14, 2009 07:15 PM Eastern Standard Time
To:	[e-mail]; [e-mail]; [e-mail]; [e-mail]; Hollenbeck, Scott
Subject:	Re: [secdir] Secdir review of draft-hollenbeck-rfc4930bis-02

>A secure authenticThe tie is what is called channel binding.

OK, obvious blip here.

A secure authenticated transport connection is established between
10.1.0.0 to the other end where the login is being attempted, say
10.2.0.0.

The trouble is that that 10.2.0.0 might be a man in the middle.
The MITM has another secure authenticated transport connection to
Bob's host, 10.3.0.0.

Bob sends the "login Bob bobscleartextpassword" over its secure
transport connection, which ends at the MITM at 10.2.0.0.

The MITM retransmits the "login Bob bobscleartextpassword" over the
secure transport connection to 10.1.0.0, impersonating Bob.

This is possible because there is no tie between the EPP ID of "Bob"
and the secure transport id of 10.2.0.0.

The tie is what is called channel binding.

You can look at RFC5056 for more information or at 
http://www.saunalahti.fi/~asokan/research/mitm.html for another
discussion with a rather detailed example for PEAP.

It might be worth pointing out that draft-ietf-sasl-gs2-14 talks
about Using GSS-API Mechanisms in SASL, and supports channel binding.

--Sandy