Re: [cti-stix] STIX Indicator Proposal

On 9/06/2017 23:46, "Jason Keirstead" <Jason.Keirstead@ca.ibm.com> wrote:

This is indeed a very apt analogy to the problem we're trying to solve here...

Now that Gary has explained his proposal more... I agree with @jmg that I am not a fan of this approach, namely because it would require continuously modifying the observed_data which doesn't make much sense, unless we want to totally re-define what observed_data is.

I could get behind a set of relationships from an indicator object to pre-existing observed_data like I described though (the relationship becomes the "highlighter pen")

-
Jason Keirstead
STSM, Product Architect, Security Intelligence, IBM Security Systems
www.ibm.com/security

Without data, all you are is just another person with an opinion - Unknown

From: Jerome Athias <jerome.athias@protonmail.com>
To: "Katz, Gary CTR DC3\\\\DCCI" <Gary.Katz.ctr@dc3.mil>
Cc: "'cti-stix@lists.oasis-open.org'" <cti-stix@lists.oasis-open.org>
Date: 06/09/2017 02:05 AM
Subject: Re: [cti-stix] STIX Indicator Proposal
Sent by: <cti-stix@lists.oasis-open.org>

My 2c
I do like the idea behind that.

Sounds like you have a large piece of writing, and want to avoid writing a stand-alone summary by using an highlighter pen.

That would be worth exploring a solution imho.

-------- Original Message --------
Subject: [cti-stix] STIX Indicator Proposal
Local Time: June 8, 2017 6:49 PM
UTC Time: June 8, 2017 3:49 PM
From: Gary.Katz.ctr@dc3.mil
To: 'cti-stix@lists.oasis-open.org' <cti-stix@lists.oasis-open.org>

I would like to provide another alternative to cover the issues associated
with analysts creating indicators and the objects they are based upon.
There are definitely some cons to this approach, but I believe it does meet
the core issue and at the least it should hopefully start some new
discussion on the topic.

Problem:
Currently analysts need to capture an IP address, email address or other
atomic indicators in two ways, first as part of observed data or
infrastructure and then again as an indicator within a pattern. Not all
IPs, FQDNs, email addresses, etc. are indicators but a large majority are
and large volumes of these types of indicators are captured on a daily
basis. While individual products can be built to alleviate the extra work
required to maintain this information in two locations (the indicator object
and in the analysis (i.e. observed data, infrastructure, etc.), STIX should
be designed to encourage good practices and minimize the need for systems to
hide inefficiencies in the standard.

Proposed Solution:
This solution does leave the opportunity for indicators to be included
within a document in two ways, but encourages atomic indicators to be
represented in one way, while complex indicators to be represented in
another way. Many properties within objects can also be atomic indicators.
This proposal suggests that any properties that are also an atomic indicator
have an 'i_' in front of the property name, while if that property was not
an indicator it would not have an 'i_'. The Indicator object would be used
to store complex indicators (i.e. patterns), although atomic indicators
could still also be stored using this approach (hence the two ways to
represent an indicator).

For example:
{
"type": "observed-data",
"id": "observed-data--b67d30ff-02ac-498a-92f9-32f845f448cf",
"created_by_ref": "identity--f431f809-377b-45e0-aa1c-6a4751cae5ff",
"created": "2016-04-06T19:58:16.000Z",
"modified": "2016-04-06T19:58:16.000Z",
"first_observed": "2015-12-21T19:00:00Z",
"last_observed": "2015-12-21T19:00:00Z",
"number_observed": 50,
"objects": {
"0": {
"type": "email-addr",
"i_value": "badguy@harpoons.com",
"display_name": "Bad Guy"
},
"1": {
"type": "email-addr",
"value": "victim@clicksonanything.com",
"display_name": "Vic"
},
}
}

Two email addresses are represented within the objects. badguy@harpoons.com
is an indicator, while victim@clicksonanything.com is not an indicator.
This allows users (or implementers) to easily create atomic indicators
without having to represent the email address within the context of the
event and then separately create an indicator object with the same email
address, linking the two together.

In order for this approach to work, we would need to define how each data
type (including complex datatypes, such as windows-registry-value-type)
would be used as an indicator. In most cases this would be simple, but in
complex datatypes such as windows-registry-value-type, we would need to
specify how the key and values are used to create an indicator.

I do not believe this functionality would need to go in the 2.0 release of
STIX. In my view, this does not break backwards compatibility, although it
is a fairly significant change that would break forwards compatibility.
It also is a little be it of a hack, which I'm not a fan of and puts extra
work onto the developer to support the capability. Truthfully, I'd rather
put more work on the developer to make things easier on the users
rather than making it easier on the developer to implement something
that puts the burden onto the user.

Interested in everyone's thoughts,
-Gary

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