Re: [TLS] Breaking into TLS for enterprise "visibility" (don't do it)

Ion Larranaga Azcue <ilarra@s21sec.com> Sat, 24 March 2018 19:37 UTC

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From: Ion Larranaga Azcue <ilarra@s21sec.com>
To: Jim Reid <jim@rfc1035.com>, Dan Brown <danibrown@blackberry.com>
CC: "tls@ietf.org" <tls@ietf.org>
Thread-Topic: [TLS] Breaking into TLS for enterprise "visibility" (don't do it)
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Date: Sat, 24 Mar 2018 19:37:34 +0000
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Subject: Re: [TLS] Breaking into TLS for enterprise "visibility" (don't do it)
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I recognize I may lack context, because I have only seen Steve Fenter's slides, but apart from it not reaching consensus, the scenario it presents (user connecting to online banking service) seems to be visibility of connections from the internet to internal servers. 

I think that not even visibility proponents agree between them, as sometimes they seem to require "server-to-server" visibility within the data center while periodically use cases appear (such as the one you mention) where traffic to be decrypted goes from internet to the internal network (or even viceversa). I'm starting to understand someone who some months ago said this looked like playing "whack-a-mole".

Besides, from what I understand from Steve Fenter's proposal (I may be wrong because I have seen only the slides) , they seem to go for non-visible TLS 1.3 connections from the client to the external layers of the network, and visible TLS 1.3 connections within their internal network. This would match the idea of "visibility only within the datacenter" but in my opinion it requires a finalization of the external tunnel and creation of a new internal one. At that point you obviously have the clear text and you could move your monitor tasks to that point.

So maybe it's because the presentation is obsolete or because I lack context but... no, I don't think those specific slides are a valid example today.

________________________________________
De: TLS <tls-bounces@ietf.org>; en nombre de Jim Reid <jim@rfc1035.com>;
Enviado: sábado, 24 de marzo de 2018 16:56
Para: Dan Brown
Cc: tls@ietf.org
Asunto: Re: [TLS] Breaking into TLS for enterprise "visibility" (don't do it)

> On 19 Mar 2018, at 15:18, Dan Brown <danibrown@blackberry.com>; wrote:
>
> PS: I never directly worked on enterprise security (usually, I just think about the math of basic crypto primitives), but I don't recall hearing about such a "visibility" feature in the enterprise security work of colleagues (whom I do _not_ speak for), e.g. one system used forward-secure ECMQV to establish a connection between smartphones and the enterprise network.

Hearsay anecdote is not evidence. :-)

There are use cases in enterprise networks, notably in banking and finance. Some of these were presented to the TLS WG. [See Steve Fenter’s presentation at IETF97.] However the WG did not reach consensus on adopting the relevant drafts as work items.