Allan (and all),
I think this is a really profound realization. I have been coming at this with a âstate-basedâ idea, as in âgive me everything you know about Xâ. Having worked in a SOC, I also realize the use cases for âevent-basedâ data. I, for one,
would be curious about your possible ideas for being able to represent both.
Thanks,
Sarah Kelley
Lead Cybersecurity Engineer, T8B2
Defensive Operations
The MITRE Corporation
703-983-6242
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 â thanks for sharing.
One of the things that Iâve realized as part of reviewing the use cases is the differences in how we talk about things.
Iâve come to the conclusion that we are talking about 2 different aspects of our problem set.
- Event-based
Vs
- 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, ipsâ.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
- Sending discrete events that have been observed at a specific time and any associated meta data to that event
- 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.
Allan
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
yesterdayâs 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 Allanâs 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 canât 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 wonât 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.
-Gary
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) â 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
CTI TC:
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
Description
Submitter: Ms. Jane Ginn |
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