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

From
Sarah Kelley <>
Date
2015-11-12T12:43:05+00:00
ID
Thread
Re: [cti-stix] Re: [cti-cybox] Revoke Cybox Observable
I can give you two very good reasons for Deleting data, as we have both situations in our database currently.

You input the data wrong in the first place. Example: You’re typing out an IP address. You mean to type 1.2.3.4 and instead you type 1.2.3.5. The second IP address is not right. It was never right. But now will live on in infamy as there is no way to purge
 it (barring the solution that Aharon mentioned Soltra is working). This is true even if the data never leaves our system via a feed, it’s now clogging up our database with incorrect information. (This was the main reason for creating orphaned observables,
 not linked to an indicator, and purging the orphans.) 

Policy violations. We are getting data from multiple different sources. Our policy with one of those sources states that we CAN NOT link it to data from any other source. So if this source and a second source give us the same information, and both live
 in the database simultaneously, we are in violation of our policy with our first provider. Doing this could cause us serious issues, and could cause us to lose out on that first valuable source of information because we can no longer protect the data as we
 were instructed. We need the ability to delete one of those instances.

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: Cory Casanave <>

Date: Wednesday, November 11, 2015 at 8:44 AM

To: Jerome Athias <>, Sarah Kelley <>

Cc: "Jordan, Bret" <>, Ivan Kirillov <>, Ali Khan <>,
 "" <>, "" <>

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

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 Athias

Sent: Tuesday, November 10, 2015 9:08 PM

To: Sarah Kelley

Cc: Jordan, Bret; Ivan Kirillov; Ali Khan; 
; 


Subject: [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 PM

To: 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,

Ivan

On 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 a

conversation 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 the

link to the current Cybox observable, and creating a new observable. This

leaves lots of orphaned observables in our database that we really need to

have the ability to purge. The understanding we have is that currently

Cybox doesn’t support any sort of revoke/purge like Stix does.

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

On 11/10/15, 11:06 AM, " on behalf of

Kirillov, Ivan A." < on behalf of

> wrote:

Great question Ali; unfortunately I don’t have much insight into this

topic. Moving this to the STIX list - I think revocation is more specific

to STIX (though it clearly touches upon CybOX as well).

Regards,

Ivan

On 11/10/15, 11:00 AM, " on behalf of

Jerome Athias" < on behalf of

> wrote:

Potential review of this

https://stixproject.github.io/data-model/1.2/indicator/ValidTimeType/

Suggestions welcome

2015-11-10 18:48 GMT+03:00 Ali Khan <>:

What is the cybox committees discussion so far for future versions to

support ability to revoke and remove completely a cybox observable

that was

created and then shared but now there is a need to remove it.

Thank You

Ali Khan

Lead Analyst

SOLTRA | An FS-ISAC & DTCC Company

Tampa, fl 33647

813.470.2197 | 


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