Re: [cti-stix] [cti-cybox] Revoke Cybox Observable

From
Jordan, Bret <>
Date
2015-11-11T16:37:05+00:00
ID
Thread
Re: [cti-stix] [cti-cybox] Revoke Cybox Observable
I kind of view all of this as people making assertions about something.  Those assertions can be good, bad, valid, invalid, only for a defined time frame etc.  Further, people can make assertions about your assertions.  You say this threat actor is using this TTP to run this campaign and attack these users types at these companies by doing XYZ..    Someone may come along and challenge part of that assertions and say it is not XYZ but rather ABC and DEF..  

From hearing everyones complaints about versioning, I think that is something we should try and fix in the next 7 days.  Lets identify the things that should be easy wins to figure out, and lets tackle them one at a time and fix them.  

Thanks,

Bret

Bret Jordan CISSP
Director of Security Architecture and Standards | Office of the CTO

Blue Coat Systems

PGP Fingerprint: 63B4 FC53 680A 6B7D 1447  F2C0 74F8 ACAE 7415 0050

"Without cryptography vihv vivc ce xhrnrw, however, the only thing that can not be unscrambled is an egg." 

On Nov 11, 2015, at 06:44, Cory Casanave <> wrote:

I would like to strongly “+1” the idea of using the relationships as a basis for versioning. Deleting data is so 20th century!

 

If you consider each instance of these relationships a “statement” (or fact) stated by some party at some time, it will always be true that this  party said what they said when they said it. In this area of threats, such “historical” statements can be very important even if they are no longer considered “true” by some party (i.e. some statements that made the U.S. go to war in Iraq ). As these statements (relationship instances) are already first-class things they can have a timeframe and confidence. We can say “that statement is invalid” or “That set of statements is not longer true”. If some implementation wants to interpret that as a “delete”, that would be fine but others may want a record of such statements (U.S. national archives likes to do such things).

 

Most of the infrastructure is already in place to do this, relationships have identity. Adding “second order” statements about them such as “superseded by” or “end date” provides for a very robust distributed knowledge base, which is what we are fundamentally trying to support.

 

-Cory

 

From:  [mailto:] On Behalf Of Jerome AthiasSent: Tuesday, November 10, 2015 9:08 PMTo: Sarah KelleyCc: Jordan, Bret; Ivan Kirillov; Ali Khan; ; : [cti-stix] Re: [cti-cybox] Revoke Cybox Observable

 

While implementation dependent, imho, the top construct Relationship (remember top of our todo list) will help.

Would be 'easy' to implement a purge procedure of all observables that don't have a Relationship created more than x month/week ago

(Similar to logs or backups/archives management/roll process)

 

Should we finalize the Relationship?On Tuesday, 10 November 2015, Sarah Kelley <> wrote:

At this point, we’re currently just trying to clean up our own database. I’m sure there is a much wider issue involved, but our current context is that we have the same observable in our system five different times (which is obviously unnecessary). The only things that changed were things like TLP, or “Hey, I fat-fingered something!” I understand the concern about "what does it mean to revoke a fact", but what if it’s just wrong? You type 1.1.1.1, and you really meant 2.2.2.2? The first is not correct, but currently is lingering in the system, even after unlinking it from the indicator. 

 

Sarah Kelley

Senior CERT Analyst

Center for Internet Security (CIS)

Integrated Intelligence Center (IIC)

Multi-State Information Sharing and Analysis Center (MS-ISAC)

1-866-787-4722 (7×24 SOC)

Email: 

www.cisecurity.org

Follow us @CISecurity

 

 

From: "Jordan, Bret" <>Date: Tuesday, November 10, 2015 at 1:16 PMTo: Ivan Kirillov <>Cc: Sarah Kelley <>, Unknown Unknown <>, Ali Khan <>, "" <>, "" <>Subject: Re: [cti-cybox] [cti-stix] Re: [cti-cybox] Revoke Cybox Observable

 

We have talked about this a lot in the past, in regards to STIX, and I now view this as an implementation or process related issue.  The reason for that is you can not guarantee that the other end of the link will honor your request.  Maybe in "like" systems, meaning all systems built by EclecticIQ or Soltra, you would have some level of success.  

 

But when you span across products there is no guarantee that they have implemented it in their code, nor that the administrator will allow it.  Requests like that may go in to a bucket for human review.  

 

 

Thanks,

 

Bret

 

 

 

Bret Jordan CISSP

Director of Security Architecture and Standards | Office of the CTO

Blue Coat Systems

PGP Fingerprint: 63B4 FC53 680A 6B7D 1447  F2C0 74F8 ACAE 7415 0050

"Without cryptography vihv vivc ce xhrnrw, however, the only thing that can not be unscrambled is an egg." 

 

On Nov 10, 2015, at 11:09, Kirillov, Ivan A. <> wrote:

 

Thanks for the context, Sarah - very helpful.To me, this comes down to being a language versus process question - that is, is Observable revocation something that should be addressed as part of the CybOX language, or should it be considered more as part of the processes in which CybOX is used? I’m leaning towards the latter, for the reason that the notion of revocation around Observables is something that doesn’t seem to fit as part of the data model around them. This is because, at their core, Observables represent some cyber “fact”, and what it does it mean to revoke a “fact”? At least with Indicators, you can argue that the Indicator may no longer be valid, or that its pattern is incorrect. With Observables, I think the semantics of revocation are not as clear and may not really make sense. At least in your case, it seems like we may need to consider defining some sort of garbage collection process, where Observables (and any other id-able CybOX/STIX entities) that were referenced and/or embedded in another entity and then no longer referenced be pruned from the datastore.Regards,IvanOn 11/10/15, 12:31 PM, " on behalf of Sarah Kelley" < on behalf of > wrote:

Just to give a little context around this question, this came up in aconversation between Ali (well, several Soltra people) and myself today.In our instance of Soltra Edge, we have (on many occasions) had to ‘edit’an observable. Currently this involves editing the indicator, deleting thelink to the current Cybox observable, and creating a new observable. Thisleaves lots of orphaned observables in our database that we really need tohave the ability to purge. The understanding we have is that currentlyCybox doesn’t support any sort of revoke/purge like Stix does.Sarah KelleySenior CERT AnalystCenter for Internet Security (CIS)Integrated Intelligence Center (IIC)Multi-State Information Sharing and Analysis Center (MS-ISAC)1-866-787-4722 (7×24 SOC)Email:  us @CISecurityOn 11/10/15, 11:06 AM, " on behalf ofKirillov, Ivan A." < on behalf > wrote:

Great question Ali; unfortunately I don’t have much insight into thistopic. Moving this to the STIX list - I think revocation is more specificto STIX (though it clearly touches upon CybOX as well).Regards,IvanOn 11/10/15, 11:00 AM, " on behalf ofJerome Athias" < on behalf > wrote:

Potential review of thishttps://stixproject.github.io/data-model/1.2/indicator/ValidTimeType/Suggestions welcome2015-11-10 18:48 GMT+03:00 Ali Khan <>:

What is the cybox committees discussion so far for future versions tosupport ability to revoke and remove completely a cybox observablethat wascreated and then shared but now there is a need to remove it.Thank YouAli KhanLead AnalystSOLTRA | An FS-ISAC & DTCC CompanyTampa, fl 33647813.470.2197 | 

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