Re: [EXT] [cti-users] trying to understand the "Sighting" object

Forrest,

Let me give a concrete examples... Say company example.com created and shared an indicator that identifies beaconing traffic for Malware sample X. That indicators identifies 50 URLs and IPs that the Malware is known to talk to.

You get that indicator and use it in your system / infrastructure. At some point that indicator fires and you get a hit.. You could tell example.com:

1) You saw the indicator but not tell them what you saw or where you saw it. This would be a one-armed Sighting relationship that point to the Indicator and nothing else.

2) You saw the indicator and the URLs you saw were badstuff.com and badactor.com. This would be a Sighting relationship that points to the Indicator and some Observed Data (the cyber observables).

3) You saw the indicator and the URLs you saw were badstuff.com and bactor.com. You also saw this in the health sector in France. This would be a Sighting relationship that points to the Indicator, some Observed Data (URLs), an Identity object (health sector), and a Location object (France).

If we were to do item 3 with the general purpose Relationship object, then you would need to send 3 JSON objects. But the Sighting relationship object allows you do include all three edges in a single JSON object.

Does that help?

Bret

Ok, so to avoid creating an additional SDO for what is theoretically the same indicator (I caveat that because there could be a false positive observance), you are creating a new relationship object for what are essentially additional properties of the previous indicator SDO relating to different observances of the indicator at a different location (“was also seen by me”, “when,” “where,”. Etc).

Then it is up to the analyst how to process that data (e.g., the example you provided below). I think I understand.

I’m not sure the graphic on the Walk-Thru depicts your explanation, however I’m not sure how to improve on it to do so. Maybe just the additional “sighting of” edge and drop the “sighting” node?

Thanks!

Forrest

Forrest B. Hare, PhD

Solutions Architect

Cyberspace Operations
571-419-0084 | forrest.b.hare@SAIC.com

saic.com |@SAICinc

Redefining Ingenuity ^™

For Cyber Support Requests, please go to:

https://saicito.service-now.com/kpc?id=kpc_cat_item&sys_id=3b4a1343139f7600f6f4b53a6144b01b

From: Bret Jordan <Bret_Jordan@symantec.com>
Sent: Monday, September 10, 2018 11:50 AM
To: Hare, Forrest B. <Forrest.B.Hare@saic.com>; cti-users@lists.oasis-open.org
Subject: Re: [EXT] [cti-users] trying to understand the "Sighting" object

Forrest,

Thank you for the question. A Sighting object in STIX is just a relationship (edge in the graph). The reason we did not use the general purpose Relationship object is we wanted some operational efficiencies for transport. So the STIX Sighting relationship object has the ability to do the following:

1) Say the indicator is good or more specially "was seen" but without any context. Some organizations can not share other details other than "thumbs up" this indicator is good and I saw it.

2) Say the indicator was seen and here are the exact things I saw. Indicator -> Sighting -> Observed Data

3) Say the indicator was seen and this is where it was seen. Indicator -> Sighting -> Identity / Location

This means you can also say what was seen and where it was seen in a single payload. Thus multiple edges in a single JSON object. This is why the Sighting relationship object is "special".

One of the big problems is in the way we talk about Sighting. We talk about it as if it was a Domain Object. This is because it can sort of act like that in the use case #1 above, effectively a one-armed edge (an edge that is only connected on one side).

I would expect a system that consumes a STIX Sighting relationship object to decompose it to the various edges that it contains and represent them individually in their graph. We also need to remember that STIX is a transport serialization for sharing CTI.

Does this help? What other questions do you have ?

Thanks

Bret

From: cti-users@lists.oasis-open.org <cti-users@lists.oasis-open.org> on behalf of Hare, Forrest B. <Forrest.B.Hare@saic.com>
Sent: Monday, September 10, 2018 9:27:15 AM
To: cti-users@lists.oasis-open.org
Subject: [EXT] [cti-users] trying to understand the "Sighting" object

I apologize if this is an uninformed question, but why is “sighting” an SRO and not just a new instance of an “indicator” SDO?

If it is truly an SRO, what two SDOs does it link (which I understand an SRO to do)? The example provided in the Walk-through at https://oasis-open.github.io/cti-documentation/stix/walkthrough

is a bit confusing to me because it represents “sighting” as a node and “sighting of” as an edge. This suggests there are two different objects, but the Object List at: https://oasis-open.github.io/cti-documentation/stix/intro

only lists “sighting” under the SRO section. “Relationship” is also listed there, but the graphic on the Walk Through page does not depict a “relationship” object, just the “indicates” edge. Hopefully, you can see where I am getting confused by trying to reconcile the diagram and terminology.

Thank you,