I fail to see how the current draft can be used to provide visibility to an IPS 
system in order to detect bots that are inside the bank…

On the one hand, the bot would never opt-in for visibility if it’s trying to 
exfiltrate data, so this capability would never get activated. And even if the 
bot was nice enough as to opt-in for visibility, the party responsible for 
providing the IPS with the required information is the server, which in this 
case is under control of the attacker. There is no way the attacker’s server 
will negotiate with the IPS the required keys to decrypt the channel (most 
likely it can’t even communicate with it).

And if you decide to close that connection because of the lack of visibility, 
well… 99% of TLS servers in internet will not negotiate visibility keys with 
your specific IPS, so you could as well close all TLS traffic going outside. 
And you don’t need visibility for this, only a well-configured firewall.

So, maybe I’m wrong, but I think that this specific use case (analysis of 
either malicious or legitimate clients’ traffic going from the enterprise 
network to outside servers) is not covered by the draft under discussion 
because the remote server will never negotiate the encryption keys with the 
IPS. For me, the only way to provide visibility within this case is by actively 
proxying every connection, something that proponents of the need for visibility 
don’t seem to be comfortable with, and which in my opinion does not require 
lowering the TLS protocol security level.

Or maybe I misunderstood the use case altogether…


De: TLS [mailto:tls-boun...@ietf.org] En nombre de Yoav Nir
Enviado el: jueves, 15 de marzo de 2018 5:58
Para: Rich Salz <rs...@akamai.com>
CC: tls@ietf.org
Asunto: Re: [TLS] Breaking into TLS to protect customers

Hi, Rich.

You are conflating customers and users. The customer that may be protected by 
breaking TLS in a bank’s server farm is the bank itself. An IPS system with 
visibility into the traffic may detect bots that are there to steal data or 
mine cryptocurrencies or whatever.

If the customers of the bank are protected, it’s a happy side effect 
(collateral benefit?). The object is to protect the system integrity and the 
data.

Yoav


On 15 Mar 2018, at 5:29, Salz, Rich <rs...@akamai.com<mailto:rs...@akamai.com>> 
wrote:

Some on this list have said that they need to break into TLS in order to 
protect customers.

The thing customers seem to need the most protection is having their personal 
data stolen.  It seems to happen with amazing and disappointing regularity on 
astounding scales.  Some examples include
·         retailer Target, presumably subject to PCI-DSS rules
·         Anthem health insurance, presumably a regulated industry
·         Equifax, a financial-business organization (but apparently not 
regulated)
·         Yahoo, a company created on and by and for the Internet (one would 
think they know better)
We could, of course, go on and on and on.

NONE of those organizations are using TLS 1.3.

So what kind of “protect the customer” requires breaking TLS?  And what 
benefits and increased protection will customers see?


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