Re: [TLS] network-based security solution use cases

"Nancy Cam-Winget (ncamwing)" <ncamwing@cisco.com> Wed, 08 November 2017 00:23 UTC

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From: "Nancy Cam-Winget (ncamwing)" <ncamwing@cisco.com>
To: Stephen Farrell <stephen.farrell@cs.tcd.ie>, "Flemming Andreasen (fandreas)" <fandreas@cisco.com>, Florian Weimer <fw@deneb.enyo.de>
CC: "tls@ietf.org" <tls@ietf.org>
Thread-Topic: [TLS] network-based security solution use cases
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Date: Wed, 8 Nov 2017 00:23:03 +0000
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Subject: Re: [TLS] network-based security solution use cases
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Hi Stephen,
Please see below:

On 11/7/17, 4:08 PM, "Stephen Farrell" <stephen.farrell@cs.tcd.ie>; wrote:

    
    Hiya,
    
    On 07/11/17 23:53, Nancy Cam-Winget (ncamwing) wrote:
    > Hi Stephen, Adding to Flemming’s comment,  finding “exact quotes”
    > will be difficult 
    
    I'm sorry but when making a claim that such and such a regulation
    *requires* breaking TLS then you really do need to be that precise.
[NCW] In TLS 1.2, not sure why you state *requires* as there is the visibility afforded to 
at least allow for the identity disclosure to enable white or blacklist for example.  

    > as their intent is really not to break things but
    > rather want to ensure that inspection and oversight is available to
    > affect guards/protections within an (enterprise/data center)
    > infrastructure.   That said, PCI and other regulations will have a
    > lot of documents that one has to go through….one that kind-of calls
    > explicitly to the use of packet inspection, firewalling and such is
    > in:
    > 
    > https://www.pcisecuritystandards.org/documents/SAQ_D_v3_Merchant.pdf
    
    The first mention of TLS there talks about protecting administrator
    passwords via TLS. That totally argues against deployment of any kind
    of MitM infrastructure.
[NCW] Agreed, they also state in ensuring that the newest TLS version where 
possible is used.  BUT, they also expect monitoring and troubleshooting.
    
    > 
    > It is an assessment questionnaire for vendors to evaluate their
    > compliance, the requirements speak to securing the network and
    > systems including firewalls, DMZs and the ability to do packet
    > inspection.
    
    Please point me at the specific text. Given you added PCI-DSS to
    your document I would assume you did the work already. If not,
    that's a bit odd.
[NCW] From the link above, you can look at requirements in 1.3,
also Requirement 10 details the need to monitor and provide audit trails
for network resources and cardholder data.
    
    S.
    
    
    > 
    > Thanks, Nancy
    > 
    > On 11/7/17, 3:27 PM, "Flemming Andreasen (fandreas)"
    > <fandreas@cisco.com>; wrote:
    > 
    > Thanks for taking an initial look at the document Stephen - please
    > see below for responses so far
    > 
    > On 11/7/17 4:13 AM, Stephen Farrell wrote:
    >> Hiya,
    >> 
    >> On 07/11/17 02:48, Flemming Andreasen wrote:
    >>> We didn't draw any particular line, but the use case scenarios
    >>> that we tried to highlight are those related to overall security
    >>> and regulatory requirements (including public sector)
    >> I had a quick look at the draft (will try read properly en-route
    >> to ietf-100) and I followed the reference to [1] but that only lead
    >> to a forest of documents in which I didn't find any reference to
    >> breaking TLS so far at least. Can you provide an explicit pointer
    >> to the exact document on which that claim is based?
    > For NERC, you can look under  "(CIP) Critital Infrastructure 
    > Protection". CIP-005-5 for example covers the electronic security 
    > perimeter, which has a couple of relevant requirements and associated
    > text:
    > 
    > http://www.nerc.com/_layouts/PrintStandard.aspx?standardnumber=CIP-005-5&title=Cyber%20Security%20-%20Electronic%20Security%20Perimeter(s)&jurisdiction=United%20States
    > 
    > 
    > 
    > To be clear though, the document does not specifically call out
    > breaking TLS, but it does clearly call out the need to detect
    > malicious inbound and outbound communications by leveraging an
    > "Electronic Access Point" (e.g. IDS/IPS) to enforce the Electronic
    > Security Perimeter.
    >> I'd also claim that your reference to PCI-DSS is misleading, as
    >> that same spec also explicitly calls for there to be good key
    >> management specifically including minimising the number of copies
    >> of keys, so at most, one might be able to claim that PCI-DSS is ok
    >> with people who break TLS in a nod-and-a-wink manner. But if you do
    >> have a real quote from PCI-DSS that calls for breaking TLS then
    >> please do also send that (it's been asked for a bunch of times
    >> without any answer being provided so far).
    > 
    > I will need to look more closely for such a quote - if anybody else 
    > knows of one, please chime in as well.
    > 
    > Thanks
    > 
    > -- Flemming
    > 
    > 
    >> Thanks, S.
    >> 
    >> 
    >> [1] 
    >> https://tools.ietf.org/html/draft-camwinget-tls-use-cases-00.html#ref-NERCCIP
    >
    >> 
    > 
    > 
    > 
    >