RE: [cti-stix] [cti-users] MTI Binding

["Davidson II, Mark S" <mdavidson@mitre.org>]

I think we’re wrapped around the axle a little bit on this whole topic. I’d like to try and step back and ask some basic questions:

 

1. Is anyone actually proposing JSON-LD as the MTI for STIX? I’ve seen the question asked, and I’ve seen lots of discussion. Is there somebody who would like to come forward and state their opinion that JSON-LD should be the MTI for STIX?

Note: I see this question as a higher bar than asking who thinks we should consider it – IMO the recent discussion makes it clear that we are considering it

2. There was an opinion that the proposed examples (the indicator and incident idioms) wouldn’t be sufficient for comparing size and complexity. What examples would be sufficient?

3. What toolchain is required to develop software that supports using a model without any custom code? Maybe I’m missing something, but if I have a product and I want to add STIX support, won’t developers have to write code?

I guess at its core – I hear what people are saying about models and not programming to the data syntax, I just don’t understand how that actually works (the more concrete the example the better, at least for me).

 

Thank you.

-Mark

 

From: cti-stix@lists.oasis-open.org [mailto:cti-stix@lists.oasis-open.org] On Behalf Of Jordan, Bret
Sent: Monday, October 05, 2015 10:23 PM
To: Cory Casanave <cory-c@modeldriven.com>; cti-users@lists.oasis-open.org; cti-stix@lists.oasis-open.org
Subject: Re: [cti-stix] [cti-users] MTI Binding

 

Cory,

 

Please help me understand....  

 

Say for kicks and giggles I have some structs that looks like this to consume an Indicator in a STIX package

 

type StixMessageType struct {
       Id         string                    `json:"id,omitempty"`
       IdRef      string                    `json:"idref,omitempty"`
       Timestamp  string                    `json:"timestamp,omitempty"`
       Version    string                    `json:"version,omitempty"`
       Indicators []indicator.IndicatorType `json:"indicators,omitempty"`
}

 

type IndicatorType struct {

       Id                        string                         `json:"id,omitempty"`

       IdRef                     string                          `json:"idref,omitempty"`
       Timestamp                 string                         `json:"timestamp,omitempty"`
       Version                      string                               `json:"version,omitempty"`
       Negate                       bool                                 `json:"negate,omitempty"`
       Title                        string                               `json:"title,omitempty"`
       Types                        []string                             `json:"type,omitempty"`
       AlternativeIDs               []string                             `json:"alternative_ids,omitempty"`
       Descriptions                 []common.StructuredTextType          `json:"descriptions,omitempty"`
       ShortDescriptions            []common.StructuredTextType          `json:"short_descriptions,omitempty"`
       ValidTimePositions           []ValidTimeType                      `json:"valid_time_positions,omitempty"`
       Observable                   *observable.ObservableType           `json:"observable,omitempty"`
       CompositeIndicatorExpression *CompositeIndicatorExpressionType    `json:"composite_indicator_expression,omitempty"`
       IndicatedTTP                 []common.RelatedTTPType              `json:"indicated_ttps,omitempty"`
       KillChainPhases              []common.KillChainPhaseReferenceType `json:"kill_chain_phases,omitempty"`
       TestMechanisms               []TestMechanismType                  `json:"test_mechanisms,omitempty"`
       LikelyImpact                 *common.StatementType                `json:"likely_impact,omitempty"`
       SuggestedCOAs                []SuggestedCOAsType                  `json:"suggested_coas,omitempty"`
       Handling                     []common.MarkingSpecificationType    `json:"handling,omitempty"`
       Confidence                   *common.ConfidenceType               `json:"confidence,omitempty"`
       Sightings                    *SightingsType                       `json:"sightings,omitempty"`
       RelatedIndicators            *RelatedIndicatorsType               `json:"related_indicators,omitempty"`
       RelatedCampaigns             *RelatedCampaignReferencesType       `json:"related_campaigns,omitempty"`
       RelatedPackages              []common.RelatedPackageRefType       `json:"related_packages,omitempty"`
       Producer                     *common.InformationSourceType        `json:"producer,omitempty"`
}

And lets say I get an indicator over the wire that looks something like this, built directly from the STIX 1.2 schema.  

 

{
    "stix_package": {
        "id": "example:package-1ad2aab5-1707-4fcc-8fd2-ebae152adeec",
        "indicators": [
            {
                "id": "example:indicator-8571137a-32a2-4934-8077-2129475813af",
                "idref": "companyfoo:indicator-1234-1234-1234-1234",
                "timestamp": "2015-10-05T20:03:23-06:00",
                "version": "1.2.1",
                "title": "Some really neat indicator that we found",
                "type": [
                    "URL Watchlist"
                ],
                "alternative_ids": [
                    "CV-2014-12-12345",
                    "CV-2015-02-54321"
                ],
                "descriptions": [
                    {
                        "id": "example:text-8769b510-9e76-4573-9778-864a51f052ae",
                        "format": "text/plain",
                        "value": "Some long description"
                    }
                ],
                "short_descriptions": [
                    {
                        "id": "example:text-12170f79-62f4-48d9-9a97-d7077f05714f",
                        "format": "text/plain",
                        "value": "Some shorter description"
                    }
                ]
            }
        ]
    }
}

 

We have a version field to say what version of an indicator it is and we know the type because it is in an indicator blob inside a stix_package blob.  

 

How does adding namespace elements make this more clear? 

 

I can easily parse this indicator and do interesting things with it.  I can parse the TTPs that reference it and do things with them.  I understand all of the fields in the indicator package because they are all well documented on the Github site [1] for Indicators.  So I can either dump this data in to a relational database or in to a document database like MongoDB.  

 

Please help me understand why namespaces are required for structured data that is well defined.  Like I said before, I can totally get and fully understand the need for JSON-LD in the open web.  It makes perfect sense when you need this to share say random profile data between two or more entities (twitter, Facebook, youtube, etc).  But we are not transporting random CTI, it will be in STIX.  So alternative_ids are Alternative IDs, and a title is a Title.  I do not see how JSON-LD helps us in anyway other than making a case for RDF over UML/OWL as RDF can work with JSON-LD.  

 

The only value I can see for JSON-LD is if we want to allow overloading.  So I can make my own Indicator format and not adhere to the STIX version of an Indicator.  In that case, yes, I can see the value, but I can also see the madness and chaos that would come from it.  

 

[1] - http://stixproject.github.io/data-model/1.2/indicator/IndicatorType/

 

 

Thanks,

 

Bret

 

 

 

Bret Jordan CISSP

Director of Security Architecture and Standards | Office of the CTO

Blue Coat Systems

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