I am confused on the purpose of this field - Isn't that the purpose of the sighting object?
And furthermore, since no one can update an object except it's creator - only they can update this last_seen field. So it will either stay stale forever, *or* they will constantly update their object whenever they see it, *and* submit a sighting? Or... ???
-
Jason Keirstead
STSM, Product Architect, Security Intelligence, IBM Security Systems
www.ibm.com/security | www.securityintelligence.com
Without data, all you are is just another person with an opinion - Unknown 
Sarah Kelley ---11/17/2016 03:03:27 PM---I’m mostly ambivalent about adding last_seen. I can see why it would be good to have, for instance i
From: Sarah Kelley <Sarah.Kelley@cisecurity.org>
To: "cti@lists.oasis-open.org" <cti@lists.oasis-open.org>
Date: 11/17/2016 03:03 PM
Subject: Re: [cti] Add last_seen to campaign and intrusion set
Sent by: <cti@lists.oasis-open.org>
I’m mostly ambivalent about adding last_seen.
I can see why it would be good to have, for instance if the last time you saw an intrusion set was 3 years ago, you can possibly assume they’ve moved on. However, my concern would be how would you keep that field up to date? Would it be automatically updated via a sighting? Or would an analyst manually adjust it? Both? Because I can see why an analyst would want to be able to adjust that field, but what happens if they forget? Then it’s suddenly inaccurate, and if you’re basing any analysis on that field it’s now wrong.
Sarah Kelley
Senior Cyber Threat Analyst
Center for Internet Security (CIS)
Integrated Intelligence Center (IIC)
Multi-State Information Sharing and Analysis Center (MS-ISAC)
1-866-787-4722 (7㈴ SOC)
Email: cert@cisecurity.org
www.cisecurity.org
Follow us @CISecurity
From: <cti@lists.oasis-open.org> on behalf of Allan Thomson <athomson@lookingglasscyber.com>
Date: Tuesday, November 15, 2016 at 6:05 PM
To: "Wunder, John A." <jwunder@mitre.org>, "cti@lists.oasis-open.org" <cti@lists.oasis-open.org>
Subject: Re: [cti] Add last_seen to campaign and intrusion set
John – thanks for sending this email.
I agree with the proposal to add last_seen and also agree with the definition that last_seen is just the last time this entity was seen.
It does not implicitly or explicltly say that the entity is ‘over’ or ‘stopped operating’.
allan
From: "cti@lists.oasis-open.org" <cti@lists.oasis-open.org> on behalf of "Wunder, John" <jwunder@mitre.org>
Date: Tuesday, November 15, 2016 at 9:35 AM
To: "cti@lists.oasis-open.org" <cti@lists.oasis-open.org>
Subject: [cti] Add last_seen to campaign and intrusion set
All,
One of the suggestions we discussed on the call today was the idea of adding a field “last_seen” to the campaign and intrusion set objects. Those objects currently have a “first_seen” field, which describes the first time activity related to them was observed…the suggestion is of course that you should be able to also describe the last time you saw activity related to that campaign/intrusion set.
One important concern is that we want to make sure the implication is NOT that having a “last_seen” field means the campaign is “over”. The producer would be saying “here’s the last time I saw X”, not “here’s the last time I saw X and I don’t expect to see it again”.
Are there any objections to this, or other considerations that we should think about when defining it? Adding a field this late in the game needs to be done carefully and we want to make sure we don’t add something we shouldn’t. Gary and Sarah, you two in particular have mentioned planned usage of campaign and intrusion set. Do you see any concerns with adding this field? And, I guess, do you see the value in adding it…would it be useful to have?
If we did add “last_seen”, we would also add “last_seen_precision” to capture the precision of the last_seen field per our rules about timestamps.
Thanks,
John
Campaign: https://docs.google.com/document/d/1S5XhY6F5OT599b0OuHtUf8IBzFvNY8RysFHIj93DgsY/edit#heading=h.pcpvfz4ik6d6
Intrusion Set: https://docs.google.com/document/d/1S5XhY6F5OT599b0OuHtUf8IBzFvNY8RysFHIj93DgsY/edit#heading=h.5ol9xlbbnrdn
...
This message and attachments may contain confidential information. If it appears that this message was sent to you by mistake, any retention, dissemination, distribution or copying of this message and attachments is strictly prohibited. Please notify the sender immediately and permanently delete the message and any attachments.
. . .