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Subject: RE: [EXT] RE: [cti] Option 1 vs. Option 7 Powerpoint Example

Hey all,


Bret alluded to some changes I suggested…I had kept these to a small group because I wasn’t sure whether it would really help the conversation, but maybe it’s time to share them.  It was also the hybrid proposal I tried and failed to describe at the F2F.


I didn’t really have this terminology at the time, but the changes are kind of along the lines of acknowledging the distinction that Allan brought up about about stateful vs. event-based information. The way I would think about it, the “stateful” relationships would be described using standard SROs using Observed Data as a container, while the description of an object itself (e.g. something you collected from a network observation) should be defined all in one place using our current approach. This enables the important use cases like relating another SDO to an observable object or describing like, domain name resolution, but doesn’t require that everyone rewrite how they currently produce an observable object definition.


Link is here: https://gist.github.com/johnwunder/a72eea28c6c1ad3a570b55d6a60583f7


FWIW I do think that the use case to capture relationships between other SDOs and observable objects are important, as is the ability to describe things like domain name resolutions in a more intuitive way. That’s what I came up with this option. It may not be exactly what the Option 1 folks want, but it does let you describe these things so that we can’t currently and so gives us an option to move forward with a smaller changeset while still enabling these use cases.




From: cti@lists.oasis-open.org <cti@lists.oasis-open.org> On Behalf Of Kelley, Sarah E.
Sent: Thursday, November 1, 2018 7:59 AM
To: Bret Jordan <Bret_Jordan@symantec.com>; Allan Thomson <athomson@lookingglasscyber.com>; Gary Jay Katz <gary.katz@FireEye.com>; cti@lists.oasis-open.org
Subject: [cti] RE: [EXT] RE: [cti] Option 1 vs. Option 7 Powerpoint Example


I’d like to explore what you define here as option c, which I believe is close to option 7 from the original list. It seems like Observed data would basically become a container object that could contain one or more (related) observables, BUT where we also take whatever relationships from the Observables Section that need to be SROs and define them that way. The ones that are immutable could stay embedded. (The examples for this, as Sean was saying, are that something like Domain resolving to IP would be an SRO because it can change and the sender email address on an email object would be embedded as it’s fixed.)


It would almost make observed-data act like a generic wrapper around observables, so they would look SDO-ish (if you put one observable inside one observed-data object), which might solve some of the same cases that Option 1 is trying to solve.


The major hangup I can see with this approach, which would need to be fleshed out and resolved, is if we have we let observed-data act like a generic SDO that can house any observable, the relationships (SROs) become more difficult. I don’t know that they’re impossible, just more difficult.


This seems like a middle ground that might allow both camps to have (at least some of) their cake and eat it too.




Sarah Kelley

Lead Cybersecurity Engineer, T8B2

Defensive Operations

The MITRE Corporation





From: cti@lists.oasis-open.org <cti@lists.oasis-open.org> On Behalf Of Bret Jordan
Sent: Wednesday, October 31, 2018 3:23 PM
To: Kelley, Sarah E. <skelley@mitre.org>; Allan Thomson <athomson@lookingglasscyber.com>; Gary Jay Katz <gary.katz@FireEye.com>; cti@lists.oasis-open.org
Subject: [cti] Re: [EXT] RE: [cti] Option 1 vs. Option 7 Powerpoint Example




When I look at it, the problem I see / hear from Gary / Jeff / Sean / Sarah is that internal relationships on the observable container do not really work for what people need. Thus having external relationships and all their goodness is what people need.


You can do that in one of three ways.  


a) Make cyber observables top level objects (option 1 prime from previous discussions)

b) Provide some sort of deep referencing inside of Observed Data (people have consistently shot down this idea)

c) Try and pull out the relationships that really need to be external and leave the rest. (A combination of option 7 with some tweaks that John Wunder has brought up)


So options a, b, and c are technically all possible, though option b where you do deep referencing inside of an Observed Data is just awful and will probably be the no-end-to-pain.




From: cti@lists.oasis-open.org <cti@lists.oasis-open.org> on behalf of Kelley, Sarah E. <skelley@mitre.org>
Sent: Wednesday, October 31, 2018 12:04:09 PM
To: Allan Thomson; Gary Jay Katz; cti@lists.oasis-open.org
Subject: [EXT] RE: [cti] Option 1 vs. Option 7 Powerpoint Example


Allan (and all),


I think this is a really profound realization. I have been coming at this with a “state-based” idea, as in “give me everything you know about X”. Having worked in a SOC, I also realize the use cases for “event-based” data.  I, for one, would be curious about your possible ideas for being able to represent both.




Sarah Kelley

Lead Cybersecurity Engineer, T8B2

Defensive Operations

The MITRE Corporation





From: cti@lists.oasis-open.org <cti@lists.oasis-open.org> On Behalf Of Allan Thomson
Sent: Wednesday, October 31, 2018 10:44 AM
To: Gary Jay Katz <gary.katz@FireEye.com>; cti@lists.oasis-open.org
Subject: Re: [cti] Option 1 vs. Option 7 Powerpoint Example


Gary – thanks for sharing.


One of the things that I’ve realized as part of reviewing the use cases is the differences in how we talk about things.


I’ve come to the conclusion that we are talking about 2 different aspects of our problem set.


  1. Event-based


  1. State-based


From my perspective, Option 1 is really representing a state of entities and connectedness between those entities after multiple events have occurred.


Option 7 (current observed-data model) represents discrete individual events that would occur over time.


This would be similar to having a state-machine defined (I,.e. the resultant intel model) and then individual events (intel events) that cause you to update the state-model.


Think of the intel model as the campaigns, actors, email-addresses, ips….etc.


Think of the events as changes to those intel objects (i.e. observed data model).


Conflating the 2 of these is not the solution.


The question is whether we are defining STIX to communicate event-based model or a state-based model.


I think we should consider the possibility that both are valid things to do and therefore we should consider how to approach using STIX to clearly articulate when we are


  1. Sending discrete events that have been observed at a specific time and any associated meta data to that event
  2. Sending a state model that represents the collective intelligence and associated relationships across that state built up over time


I think if we recognize that both models require something different and factor that into our STIX data model discussion then we might find a way to solve both.


I have some ideas but this email is already too long.




From: "cti@lists.oasis-open.org" <cti@lists.oasis-open.org> on behalf of Gary Jay Katz <gary.katz@FireEye.com>
Date: Wednesday, October 31, 2018 at 6:20 AM
To: "cti@lists.oasis-open.org" <cti@lists.oasis-open.org>
Subject: [cti] Option 1 vs. Option 7 Powerpoint Example


Thank you to everyone for taking time to discuss Option 1 and Option 7.  As usual, Jane did an excellent job capturing the discussion, including screen shots from the presentation.  John-Mark requested that I resend out the slides from yesterday’s discussion with any updates, which I believe is valuable as it will allow us to continue the discussion over email.  As an update, I did include an optional Observed Data object in Option 1.  The inclusion of an Observed Data object would show that the producer directly observed the email with an attachment vs. indirectly having that information (ex. Gathered the information from external reporting). 


The purpose of this example is to show a very reasonable use-case for a cyber security analyst and discuss how that data can be represented in the STIX standard using either Option 1 or Option 7.  I have not created JSON versions of the example in both Option 1 and Option 7 form.  My assumption would be, to Allan’s point, that the Option 1 version is more verbose, although only slightly.  This does mean that the data size of the document is larger and to earlier points, in other use cases this difference can be even larger.  This example though highlights an even larger issue.  Option 7 does not allow some common useful relationships to be represented within the format.  Having relationships to show that a file found in an email, which analysis shows beacons to a C2 that resolved to a specific domain is not possible in Option 7.  The receiver must infer this information through 3 disjointed objects. 


Our greatest risk to adoption is not asking companies and organizations to update their STIX implementations to support Option 1 or the increase in data size for certain use cases.  Our greatest risk is having the trust of the userbase.  One day, far in the future (if we do our jobs well), analysts will not even be aware of STIX being used in the background to transfer their data.  Today though, they are paying attention, they will be asked by their leadership to look at the standard and provide their opinion on how valuable it is to adopt STIX, and analysts will not understand why they can’t represent a file found in an email has a C2 beacon that resolves to a domain (or something similar).  The answer to just trust us that the receiver is going to auto-correlate that information back together, probably won’t fly. 


Some of these issues were masked by the limited use cases possible in STIX 2.0 and 2.1.  As the standard evolves to support Malware, Infrastructure and Incident objects these issues will become very pronounced.  We will continue to put band-aids on the standard as a result of the deficiency (ex. See the malware proposal submitted by Jeff Mates and I earlier this year).  Option 1 will resolve these deficiencies.  Will it take work and effort, yes, but that work and effort will only continue to grow the longer we wait.




Some Metrics on the two implementations of the use cases:

Option 1:

8 Objects (1 optional)  (2 SDOs, 6 SOOs)

5 Embedded refs (3 optional)

6 Relationships (6 SROs)


Option 7

15 Objects* (6 SDOs, 9 cyber observables)

5 Embedded refs (2 within Malware not shown)

2 Relationships (2 SROs) – Note some relationships in the example cannot be represented in this option

* Cyber Observables are not full objects in this option.  Therefore must be embedded in an SDO but are lighter objects that take less text to represent.



From: <cti@lists.oasis-open.org> on behalf of Jane Ginn <jg@ctin.us>
Date: Tuesday, October 30, 2018 at 6:10 PM
To: "cti@lists.oasis-open.org" <cti@lists.oasis-open.org>
Subject: [cti] Groups - Weekly Working Call - Notes uploaded


Submitter's message

Here is the PDF of the notes from the Working Call. I included the figures in this version.

Best regards,

-- Ms. Jane Ginn

Document Name: Weekly Working Call - Notes

Discussed Option 1 and Option 7 for Cyber Observables
Download Latest Revision
Public Download Link

Submitter: Ms. Jane Ginn
Group: OASIS Cyber Threat Intelligence (CTI) TC
Folder: Meeting Notes
Date submitted: 2018-10-30 15:10:05


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