Re: [TLS] TLS Proxy Server Extension

David McGrew <mcgrew@cisco.com> Fri, 29 July 2011 22:24 UTC

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From: David McGrew <mcgrew@cisco.com>
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Date: Fri, 29 Jul 2011 15:24:09 -0700
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Cc: tls@ietf.org, pgladstone@cisco.com
Subject: Re: [TLS] TLS Proxy Server Extension
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On Jul 29, 2011, at 1:44 PM, Martin Rex wrote:

> Matt McCutchen wrote:
>>
>> On Wed, 2011-07-27 at 20:17 +0200, Martin Rex wrote:
>>> Only for Web-Browser scenario can I personally see a very limited
>>> value that does not amount to 100% wiretapping.
>>>
>>> Are you aware of rfc2804 "IETF Policy on Wiretapping"?
>>>
>>>  http://tools.ietf.org/html/rfc2804
>>>
>>> Standardizing MITM attacks on TLS-protected communication
>>> ("lawful intercept?") seems like an extremely bad idea to me.
>>
>> This is not wiretapping as defined in that policy.
>

Right, it's clearly not wiretapping as per RFC 2804: "Wiretapping is  
what occurs when information passed across the Internet from one party  
to one or more other parties is delivered to a third party: 1. Without  
the sending party knowing about the third party ..."   The intent of  
the work we are discussing is to ensure that the client knows about  
the third party.

>
> I *STRONGLY* disagree.  That is very much about wiretapping and
> even goes far beyond that, because it not only reveals the content
> of the communication, it also allows the "TLS proxy" to arbitrarily
> manipulate the communication in a fashion that might be entirely
> concealed to the communication peers at the end.
>
>
> I am strongly opposed to have any document describing such proxies
> published as an RFC!
>


And yet you would favor a protocol that propagates decryption keys  
around the network?

We don't have a choice about whether or not TLS proxying will be done  
on the Internet; it is being done.  What we can choose is whether or  
not the IETF improves how it is being done.

David