Very interesting ideas feedback. I would like to add this to an "open questions" part of this discussion. I think I see where you are going, but I am not yet fully sure I understand the "why" it would be needed.
Now TBH, a few days ago on the Slack channel I was arguing very heavily for something similar. Basically, having TAXII do the group/trustgroup stuff. But after some thought and listening to everyones feedback I am beginning to think my initial view was wrong and I am starting to come to middle ground with the rest of this SC. My only concern still, and I will add this to the open questions as well. If TAXII does not deal with trust groups in the spec, then do we run the risk of having non-comparable systems". I do not know the answer to this question yet, but it is one I want us to look at over time.
Bret Jordan CISSP
Director of Security Architecture and Standards | Office of the CTO
Blue Coat Systems
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"Without cryptography vihv vivc ce xhrnrw, however, the only thing that can not be unscrambled is an egg."
Hey, Jason -
Imagine that a large multinational corporation or informal sharing network (hub and spoke) wants to synchronize some or all of their TAXII trust groups. As things currently stand, that would necessarily involve out-of-band (ie, non-TAXII) communication. What I'm proposing is an optional block for sharing trust group info. Soltra Edge can encapsulate its notion of trust group data inside the soltra block. If Intelworks groks that, it can act on it. If not, it can safely disregard the data encapsulated in the block.
(Or maybe, just maybe several vendors collaborate to support interoperability.)
Extend the notion to n vendor-specific definition of trustgroups. TAXII can easily support sharing trustgroup information in-band without actually codifying any particular notion in the standard.
[again with the strawman]
Senior Security Engineer
Soltra | An FS-ISAC & DTCC Company
I agree that trust groups are likely to remain vendor-specific and hence it's pointless trying to formalize trust groups per se in TAXII 2.0.At the same time, TAXII 2.0 *should* have a mechanism for exchange of trust group data between compatible systems. If you grok a vendor's notion of trustgroups, you can do something with it. Otherwise, you can safely ignore it. I envisage this as an optional block, a la (total strawman):<trustgroups><soltra>...</soltra><intelworks>...</intelworks><trustgroups>
Cheers,Trey--Trey DarleySenior Security EngineerSoltra | An FS-ISAC & DTCC Companywww.soltra.com
From: email@example.com <firstname.lastname@example.org> on behalf of Adam Cooper <email@example.com>
Sent: Thursday, September 24, 2015 08:37
To: Jason Keirstead
Cc: Jordan, Bret; firstname.lastname@example.org
Subject: Re: [cti-taxii] Question about multiple trust group support I have to agree with Jason: trust groups can be implemented in many ways and are often vendor or technology specific. Limiting implementation options through specification under TAXII adds nothing to the core purpose of TAXII in my mind and may actually limit adoption in COTS products. Perhaps I am looking at this from a slightly purist approach but there are two things at play here: 1) the TAXII protocol, and 2) TAXII servers. The protocol should in my opinion should NOT be implementation specific and focus on the primary purpose of TAXII i.e. the exchange of cyber threat information. A TAXII server, again in my opinion, should be something that implements the protocol but can do so in any way the developer/vendor chooses provided it is compliant with the protocol standard. The TAXII server (implementation) is then able to implement things like trust groups freely. Thanks,Adam