STIXVersion 2.0. Part 1: STIX Core Concepts

Working Draft 03

19 June 2017

Technical Committee:

OASIS Cyber Threat Intelligence (CTI) TC

​Chair:

Richard Struse (Richard.Struse@HQ.DHS.GOV), DHS Office of Cybersecurity and Communications (CS&C)

​Editors:

Bret Jordan (bret_jordan@symantec.com), Symantec Corp.

Rich Piazza (rpiazza@mitre.org), MITRE Corporation

John Wunder (jwunder@mitre.org), MITRE Corporation

Additional artifacts:

This prose specification is one component of a Work Product that also includes:

Related work:

This specification replaces or supersedes:

This specification is related to:

Abstract:

Structured Threat Information Expression (STIXTM) is a language for expressing cyber threat and observable information. This document defines concepts that apply across all of STIX and defines the overall structure of the STIX language.

Status:

This Working Draft (WD) has been produced by one or more TC Members; it has not yet been voted on by the TC or approved as a Committee Draft (Committee Specification Draft or a Committee Note Draft). The OASIS document Approval Process begins officially with a TC vote to approve a WD as a Committee Draft. A TC may approve a Working Draft, revise it, and re-approve it any number of times as a Committee Draft.

URI patterns:

Initial publication URI:

http://docs.oasis-open.org/cti/stix/v2.0/csd01/part1-stix-core/stix-v2.0-csd01-part1-stix-core.docx

Permanent “Latest version” URI:

http://docs.oasis-open.org/cti/stix/v2.0/stix-v2.0-part1-stix-core.docx

(Managed by OASIS TC Administration; please don’t modify.)

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Table of Contents

​1​ Introduction        6

​1.1​ Terminology        6

​1.2​ Normative References        6

​1.3​ Non-Normative References        7

​1.4​ Overview        7

​1.4.1​ Graph-Based Model        7

​1.4.2​ STIX™ Domain Objects        8

​1.4.3​ STIX™ Relationships        8

​1.4.4​ Cyber Observables        9

​1.4.5​ STIX™ Patterning        9

​1.4.6​ Vocabularies        9

​1.4.7​ Serialization        10

​1.4.8​ Transporting STIX™        10

​1.5​ Naming Requirements        10

​1.5.1​ Property Names and String Literals        10

​1.5.2​ Reserved Names        10

​1.6​ Document Conventions        10

​1.6.1​ Naming Conventions        10

​1.6.2​ Font Colors and Style        11

​2​ Common Data Types        12

​2.1​ Boolean        12

​2.2​ External Reference        13

​2.2.1​ Properties        13

​2.2.2​ Requirements        13

​2.3​ Float        15

​2.4​ Hashes        15

​2.5​ Identifier        16

​2.6​ Integer        16

​2.7​ Kill Chain Phase        17

​2.8​ List        18

​2.9​ Open Vocabulary        18

​2.10​ String        19

​2.11​ Timestamp        19

​2.11.1​ Requirements        19

​3​ STIX™ Objects        21

​3.1​ Common Properties        21

​3.2​ IDs and References        23

​3.3​ Object Creator        23

​3.4​ Versioning        24

​3.4.1​ Versioning Timestamps        24

​3.4.2​ New Version or New Object?        25

​3.5​ Common Relationships        28

​3.6​ Reserved Properties        29

​4​ Data Markings        31

​4.1​ Marking Definition        31

​4.1.1​ Properties        31

​4.1.2​ Relationships        33

​4.1.3​ Statement Marking Object Type        33

​4.1.4​ TLP Marking Object Type        34

​4.2​ Object Markings        35

​4.3​ Granular Markings        35

​4.3.1​ Granular Marking Type        36

​4.3.1.1​ Selector Syntax        36

​5​ Bundle        38

​5.1​ Properties        38

​5.2​ Relationships        39

​6​ Vocabularies        40

​6.1​ Attack Motivation        40

​6.2​ Attack Resource Level        42

​6.3​ Hashing Algorithm Vocabulary        43

​6.4​ Identity Class        44

​6.5​ Indicator Label        45

​6.6​ Industry Sector        46

​6.7​ Malware Label        47

​6.8​ Report Label        49

​6.9​ Threat Actor Label        50

​6.10​ Threat Actor Role        53

​6.11​ Threat Actor Sophistication        54

​6.12​ Tool Label        56

​7​ Customizing STIX™        58

​7.1​ Custom Properties        58

​7.1.1​ Requirements        58

​7.2​ Custom Objects        59

​7.2.1​ Requirements        59

​8​ Conformance        60

​8.1​ Producers and Consumers        60

​8.2​ Mandatory Features        60

​8.2.1​ Versioning        60

​8.3​ Optional Features        60

​8.3.1​ Object-Level Data Markings        60

​8.3.2​ Granular Data Markings        60

​8.3.3​ Custom Properties        61

​8.3.4​ Custom Objects        61

​Appendix A. Glossary        62

​Appendix B. Acknowledgments        63

​Appendix C. Revision History        68



​1​ Introduction

Structured Threat Information Expression (STIX™) is a language and serialization format used to exchange cyber threat intelligence (CTI). STIX enables organizations to share CTI with one another in a consistent and machine readable manner, allowing security communities to better understand what computer-based attacks they are most likely to see and to anticipate and/or respond to those attacks faster and more effectively. STIX is designed to improve many different capabilities, such as collaborative threat analysis, automated threat exchange, automated detection and response, and more.

In response to lessons learned in implementing previous versions, STIX has been significantly redesigned and, as a result, omits some of the objects and properties defined in STIX 1.2.1 (see STIX™ Version 1.2.1 Part 1: Overview). The objects chosen for inclusion in STIX 2.0 represent a minimally viable product (MVP) that fulfills basic consumer and producer requirements for CTI sharing. Objects and properties not included in STIX 2.0, but deemed necessary by the community, will be included in future releases.

​1.1​ Terminology

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in [RFC2119].

All text is normative except for examples, the overview (section 1.4), and any text marked non-normative.

​1.2​ Normative References

[IEEE 754-2008]        “IEEE Standard for Floating-Point Arithmetic”, IEEE 754-2008, August 2008. [Online]. Available: http://ieeexplore.ieee.org/document/4610935/

 

 

[ISO10646]               “ISO/IEC 10646:2014 Information technology -- Universal Coded Character Set (UCS)”, 2014.  [Online]. Available: http://standards.iso.org/ittf/PubliclyAvailableStandards/c063182_ISO_IEC_10646_2014.zip

[RFC2119]                 Bradner, S., “"Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, http://www.rfc-editor.org/info/rfc2119.

 

[RFC3339]                 Klyne, G. and C. Newman, "Date and Time on the Internet: Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, http://www.rfc-editor.org/info/rfc3339.

[RFC3986]                 Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, January 2005, http://www.rfc-editor.org/info/rfc3986.

 

[RFC4122]                 Leach, P., Mealling, M., and R. Salz, "A Universally Unique IDentifier (UUID) URN Namespace", RFC 4122, DOI 10.17487/RFC4122, July 2005, http://www.rfc-editor.org/info/rfc4122.

[RFC7159]                 Bray, T., Ed., "The JavaScript Object Notation (JSON) Data Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March 2014. http://www.rfc-editor.org/info/rfc7159.txt.

 

[TLP]                          Traffic Light Protocol, Version 1.0 (TLP). (2016, Aug. 25). FIRST. [Online]. Available: https://first.org/tlp

​1.3​ Non-Normative References

[CAPEC]                    Common Attack Pattern Enumeration and Classification (CAPEC). (2014, Nov. 7). The MITRE Corporation. [Online]. Available: http://capec.mitre.org.

 

[Casey 2007]             Casey, T., Threat Agent Library Helps Identify Information Security Risks

September 2007. [Online]. Available: https://communities.intel.com/servlet/JiveServlet/downloadBody/1151-102-1-1111/Threat Agent Library_07-2202w.pdf.

[Casey 2015]             Casey, T., “Understanding Cyberthreat Motivations to Improve Defense”, Intel, February 2015. [Online]. Available: https://communities.intel.com/servlet/JiveServlet/previewBody/23856-102-1-28290/understanding-cyberthreat-motivations-to-improve-defense-paper-l.pdf.

 

[Goessner 2007]           Goessner, S., “JSONPath - XPath for JSON”, February 2007. [Online]. Available:

http://goessner.net/articles/JsonPath/.

[JSON Schema]           OASIS Cyber Threat Intelligence (CTI) TC, “cti-stix2-json-schemas”, OASIS. [Online]. Available: https://github.com/oasis-open/cti-stix2-json-schemas.

 

[Mell 2005]                Mell, P., Kent, K. and Nusbaum, J., “Guide to Malware Incident Prevention and Handling”, NIST Special Publication 800-83, November 2005. [Online]. Available: http://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-83.pdf.

 

[VERIS]                      VERIS Community Database. (n.d.). [Online]. Available: http://vcdb.org/

​1.4​ Overview

​1.4.1​ Graph-Based Model

STIX 2.0 is a connected graph of nodes and edges. STIX Domain Objects define the graph nodes and STIX relationships (including STIX Relationship Objects and embedded relationships) define the edges. The full set of STIX Domain Objects and STIX Relationship Objects are known as STIX Objects. This graph-based language conforms to common analysis approaches and allows for flexible, modular, structured, and consistent representations of CTI.

​1.4.2​ STIX™ Domain Objects

STIX 2.0 defines a set of STIX Domain Objects (SDOs): Attack Pattern, Campaign, Course of Action, Identity, Indicator, Intrusion Set, Malware, Observed Data, Report, Threat Actor, Tool, and Vulnerability. Each of these objects corresponds to a concept commonly used in CTI. Using the building blocks of SDOs alongside STIX relationships, entities can create and share broad and comprehensive CTI.

STIX Domain Objects all share a common set of properties. These common properties provide standard capabilities such as versioning, data marking (representing how data can be shared and used), and extensibility.

STIX Domain Objects are defined in STIX™ Version 2.0. Part 2: STIX Objects.

​1.4.3​ STIX™ Relationships

A relationship is a link between STIX Objects that describes the way in which the objects are related. Most relationships are represented using STIX Relationship Objects (SROs), while other special embedded relationships are represented as ID references.

The generic Relationship object is one of two SROs and is used for most relationships in STIX. This generic Relationship object contains a property called relationship_type to describe more specifically what the relationship represents. This specification defines a set of known terms to use for the relationship_type property between SDOs of specific types. For example, the Indicator SDO defines a relationship from itself to Malware with a relationship_type of indicates to describe how the Indicator can be used to detect the presence of that Malware. In addition to the terms defined in the specification, STIX also allows for custom terms to be used as the relationship type.

Currently the only other SRO (besides a generic Relationship) is the Sighting relationship object. The Sighting object is used to capture cases where an entity has "seen" an SDO, such as sighting an indicator. Sighting is a separate SRO because it contains additional properties such as count that are only applicable to Sighting relationships. Other SROs may be defined in future versions of STIX if new relationships are identified that also require additional properties not present on the generic Relationship object.

In addition to relationships created using the SROs (Relationship and Sighting), STIX also uses ID references to represent embedded relationships. Embedded relationships are simply ID reference properties on STIX Objects that contain the ID of a different STIX Object. Embedded relationships are used when the property is an inherent part of the object and not something that a third party might add or something that might require a confidence. Because they represent a simply inherent linkage and have no other properties, an SRO is not needed to represent them. An embedded relationship can only be asserted by the creator of the object ("object creator") it is contained in.

For example, the entity that created a STIX Object is an inherent, factual part of that object and therefore that information is captured in an embedded relationship contained in the created_by_ref property rather than through the use of an SRO.

Embedded relationships (ID references) are described in section 3.2 and STIX Relationship Objects (SROs) are defined in section 3 of STIX™ Version 2.0. Part 2: STIX Objects.

​1.4.4​ Cyber Observables

Some parts of the STIX language require describing structured representation of observed objects and their properties in the cyber domain. These capabilities differ from the parts of STIX used to describe higher-level concepts in many ways and are therefore contained in a separate section of the specification. The Cyber Observable sections describe one or more observed data points, for example, information about a file that existed, a process that was observed running, or that network traffic occurred between two IPs. It describes the facts concerning what happened, but not necessarily the who or when, and never the why.

Cyber Observables are defined by two documents in this specification. STIX™ Version 2.0. Part 3: Cyber Observable Core Concepts describes and defines Cyber Observable Core Concepts, which are the parts of STIX that are specific to representation of cyber observables. STIX™ Version 2.0. Part 4: Cyber Observable Objects contains a library of Cyber Observable Objects: definitions for the types of things that can be observed.

​1.4.5​ STIX™ Patterning

In order to enhance detection of possibly malicious activity on networks and endpoints, a standard language is needed to describe what to look for in a cyber environment. The STIX Patterning language allows matching against timestamped Cyber Observable data (such as STIX Observed Data Objects) collected by a threat intelligence platform or other similar system so that other analytical tools and systems can be configured to react and handle incidents that might arise. STIX Patterning is a general concept that can be used anywhere, but in STIX it is currently used by the Indicator object.

STIX Patterning is defined in STIX™ Version 2.0. Part 5: STIX Patterning.

​1.4.6​ Vocabularies

Many STIX Objects contain properties whose values can be selected from a defined set of values. These sets of values are called vocabularies and are defined in STIX in order to enhance interoperability by increasing the likelihood that different entities use the same exact string to represent the same concept. If used consistently, vocabularies make it less likely that one entity refers to the energy sector as “Energy” and another as “Energy Sector”, thereby making comparison and correlation easier.

While using predefined values from STIX vocabularies is encouraged, in some cases this is not possible or desirable. STIX supports this by defining vocabularies as “open”, where entities are permitted to use values outside of the suggested vocabulary.

STIX vocabularies are defined in section 6. Properties that are defined as open vocabularies identify a suggested vocabulary from that section. For example, the Indicator labels property, as defined in section 2.5 of STIX™ Version 2.0. Part 2: STIX Objects, uses the Indicator Label vocabulary as defined in section 6.5.

​1.4.7​ Serialization

STIX is defined independent of any specific storage or serialization. However, the mandatory-to-implement (MTI) serialization for STIX 2.0 is JSON [RFC7159]. In other words, all STIX-conformant tools have to implement support for JSON and can implement support for other serializations.

JSON schemas have been developed by members of the Cyber Threat Intelligence Technical Committee and are available in the cti-stix2-json-schemas OASIS Open Repository [JSON Schema]. The JSON schemas are informative and serve as a best effort attempt to validate that STIX 2.0 content meets the structural requirements identified in this specification. This specification is the normative description of STIX 2.0.

As JSON is the MTI serialization, all examples in this document are expressed in JSON.

​1.4.8​ Transporting STIX™

STIX 2.0 is transport-agnostic, i.e., the structures and serializations do not rely on any specific transport mechanism. A companion CTI specification, TAXII™, is designed specifically to transport STIX Objects. STIX provides a Bundle (see section 5) as a container for STIX Objects to allow for transportation of bulk STIX data, especially over non-TAXII communication mechanisms.

​1.5​ Naming Requirements

​1.5.1​ Property Names and String Literals

In the JSON serialization all property names and string literals MUST be exactly the same, including case, as the names listed in the property tables in this specification. For example, the SDO common property created_by_ref must result in the JSON key name "created_by_ref". Properties marked required in the property tables MUST be present in the JSON serialization.

​1.5.2​ Reserved Names

Reserved property names are marked with a type called RESERVED and a description text of “RESERVED FOR FUTURE USE”. Any property name that is marked as RESERVED MUST NOT be present in STIX content conforming to this version of the specification.

​1.6​ Document Conventions

​1.6.1​ Naming Conventions

All type names, property names and literals are in lowercase, except when referencing canonical names defined in another standard (e.g. literal values from an IANA registry). Words in property names are separated with an underscore (_), while words in type names and string enumerations are separated with a hyphen (-). All type names, property names, object names, and vocabulary terms are between three and 250 characters long.

​1.6.2​ Font Colors and Style

The following color, font and font style conventions are used in this document:



​2​ Common Data Types

This section defines the common types used throughout STIX. These types will be referenced by the Type column in other sections. This section defines the names and permitted values of common types that are used in the STIX information model; it does not, however, define the meaning of any properties using these types. These types may be further restricted elsewhere in the document.

Type

Description

boolean

A value of true or false.

external-reference

A non-STIX identifier or reference to other related external content.

float

An IEEE 754 [IEEE 754-2008] double-precision number.

hashes

One or more cryptographic hashes.

identifier

An identifier (ID) for a STIX Domain Object, STIX Relationship Object, Bundle, or Marking Definition.

integer

A whole number.

kill-chain-phase

A name of a kill chain phase.

list

A sequence of values ordered based on how they appear in the list. The phrasing list of type <type>is used to indicate that all values within the list MUST conform to the specified type.

open-vocab

A value from a STIX open (open-vocab) or suggested vocabulary.

string

A series of Unicode characters.

timestamp

A time value (date and time).

​2.1​ Boolean

Type Name: boolean

A boolean is a value of either true or false. Properties with this type MUST have a value of true or false.

The JSON MTI serialization uses the JSON boolean type [RFC7159], which is a literal (unquoted) true or false.

Examples

{

  ...

  "summary": true,

  ...

}

​2.2​ External Reference

Type Name: external-reference

External references are used to describe pointers to information represented outside of STIX. For example, a Malware object could use an external reference to indicate an ID for that malware in an external database or a report could use references to represent source material.

The JSON MTI serialization uses the JSON object type [RFC7159] when representing external-reference.

​2.2.1​ Properties

Property Name

Type

Description

source_name (required)

string

The source within which the external-reference is defined (system, registry, organization, etc.).

description (optional)

string

A human readable description.

url (optional)

string

A URL reference to an external resource [RFC3986].

hashes (optional)

hashes

Specifies a dictionary of hashes for the contents of the url. This SHOULD be provided when the url property is present.

external_id (optional)

string

An identifier for the external reference content.

​2.2.2​ Requirements

Examples

An external-reference to a VERIS Community Database (VCDB) [VERIS] entry

{

  ...

  "external_references": [

    {

      "source_name": "veris",

      "external_id": "0001AA7F-C601-424A-B2B8-BE6C9F5164E7",

      "url": "https://github.com/vz-risk/VCDB/blob/master/data/json/0001AA7F-C601-424A-B2B8-

             BE6C9F5164E7.json",

      "hashes": {

        "SHA-256": "6db12788c37247f2316052e142f42f4b259d6561751e5f401a1ae2a6df9c674b"

      }

    }

  ],

  ...

}

An external-reference from the CAPEC[CAPEC] repository

{

  ...

  "external_references": [

    {

      "source_name": "capec",

      "external_id": "CAPEC-550"

    }

  ],

  ...

}

 

An external-reference from the CAPEC repository with URL

{

  ...

  "external_references": [

    {

      "source_name": "capec",

      "external_id": "CAPEC-550",

      "url": "http://capec.mitre.org/data/definitions/550.html"

    }

  ],

  ...

}

 

An external-reference to ACME Threat Intel's report document

{

  ...

  "external_references": [

    {

      "source_name": "ACME Threat Intel",

      "description": "Threat report",

      "url": "http://www.example.com/threat-report.pdf"

    }

  ],

  ...

}

 

An external-reference to a Bugzilla item

{

  ...

  "external_references": [

    {

      "source_name": "ACME Bugzilla",

      "external_id": "1370",

      "url": "https://www.example.com/bugs/1370"

    }

  ],

  ...

}

An external-reference to an offline threat report (i.e., e-mailed, offline, etc.)

{

  ...

  "external_references": [

    {

      "source_name": "ACME Threat Intel",

      "description": "Threat report"

    }

  ],

  ...

}

​2.3​ Float

Type Name: float

The float data type represents an IEEE 754 [IEEE 754-2008] double-precision number (e.g., a number with a fractional part). However, because the values ±Infinity and NaN are not representable in JSON, they are not valid values in STIX.

In the JSON MTI serialization, floating point values are represented by the JSON number type [RFC7159].

Examples

{

  ...

  "distance": 8.321,

  ...

}

​2.4​ Hashes

Type Name: hashes

The Hashes type represents 1 or more cryptographic hashes, as a special set of key/value pairs. Accordingly, the name of each hashing algorithm MUST be specified as a key in the dictionary and MUST identify the name of the hashing algorithm used to generate the corresponding value. This name SHOULD either be one of the values defined in the hash-algorithm-ov OR a custom value prepended with “x_” (e.g., “x_custom_hash”).

Keys MUST be unique in each hashes property, MUST be in ASCII, and are limited to the characters a-z (lowercase ASCII), A-Z (uppercase ASCII), numerals 0-9, hyphen (-), and underscore (_). Keys SHOULD be no longer than 30 ASCII characters in length, MUST have a minimum length of 3 ASCII characters, MUST be no longer than 256 ASCII characters in length.

Examples

SHA-256 and Custom Hash

{

  "SHA-256": "6db12788c37247f2316052e142f42f4b259d6561751e5f401a1ae2a6df9c674b",

  "x_foo_hash": "aaaabbbbccccddddeeeeffff0123457890"

}

​2.5​ Identifier

Type Name: identifier

An identifier universally and uniquely identifies a SDO, SRO, Bundle, or Marking Definition. Identifiers MUST follow the form object-type--UUIDv4, where object-type is the exact value (all type names are lowercase strings, by definition) from the type property of the object being identified or referenced and where the UUIDv4 is an RFC 4122-compliant Version 4 UUID. The UUID MUST be generated according to the algorithm(s) defined in RFC 4122, section 4.4 (Version 4 UUID) [RFC4122].

The JSON MTI serialization uses the JSON string type [RFC7159] when representing identifier.

​Examples

{

  ...

  "type": "indicator",

  "id": "indicator--e2e1a340-4415-4ba8-9671-f7343fbf0836",

  ...

}

{

  ...

  "type": "threat-actor",

  "id": "threat-actor--5ee9db36-4a1e-4dd4-bb32-2551eda97f4a",

  ...

}

​2.6​ Integer

Type Name: integer

The integer data type represents a whole number. Unless otherwise specified, all integers MUST be capable of being represented as a signed 64-bit value ([-(2**63)+1, (2**63)-1]). Additional restrictions MAY be placed on the type as described where it is used.

In the JSON MTI serialization, integers are represented by the JSON number type [RFC7159].

Examples

{

  ...

  "count": 8,

  ...

}

​2.7​ Kill Chain Phase

Type Name: kill-chain-phase

The kill-chain-phase represents a phase in a kill chain, which describes the various phases an attacker may undertake in order to achieve their objectives.

The JSON MTI serialization uses the JSON object type [RFC7159] when representing kill-chain-phase.

Property Name

Type

Description

kill_chain_name (required)

string

The name of the kill chain. The value of this property SHOULD be all lowercase (where lowercase is defined by the locality conventions) and SHOULD use hyphens instead of spaces or underscores as word separators.

phase_name (required)

string

The name of the phase in the kill chain. The value of this property SHOULD be all lowercase (where lowercase is defined by the locality conventions) and SHOULD use hyphens instead of spaces or underscores as word separators.

When referencing the Lockheed Martin Cyber Kill Chain™, the kill_chain_name MUST be lockheed-martin-cyber-kill-chain.

Examples

Example specifying the “reconnaissance” phase from the Lockheed Martin Cyber Kill Chain

{

  ...

  "kill_chain_phases": [

    {

      "kill_chain_name": "lockheed-martin-cyber-kill-chain",

      "phase_name": "reconnaissance"

    }

  ],

  ...

}

Example specifying the “pre-attack” phase from the “foo” kill-chain

{

  ...

  "kill_chain_phases": [

    {

      "kill_chain_name": "foo",

      "phase_name": "pre-attack"

    }

  ],

  ...

}

​2.8​ List

Type Name: list

The list type defines a sequence of values ordered based on how they appear in the list. The phrasing “list of type <type>” is used to indicate that all values within the list MUST conform to the specified type. For instance, list of type integer means that all values of the list must be of the integer type. This specification does not specify the maximum number of allowed values in a list, however every instance of a list MUST have at least one value. Specific STIX object properties may define more restrictive upper and/or lower bounds for the length of the list.

Empty lists are prohibited in STIX and MUST NOT be used as a substitute for omitting the property if it is optional. If the property is required, the list MUST be present and MUST have at least one value.

The JSON MTI serialization uses the JSON array type [RFC7159], which is an ordered list of zero or more values.

Examples

{

  ...

  "observed_data_refs": [

    "observed-data--b67d30ff-02ac-498a-92f9-32f845f448cf",

    "observed-data--c96f4120-2b4b-47c3-b61f-eceaa54bd9c6",

    "observed-data--787710c9-1988-4a1b-9761-a2de5e19c62f"

  ],

  ...

}

​2.9​ Open Vocabulary

Type Name: open-vocab

The open-vocab type is represented as a string. For properties that use this type there will be a list of suggested values, known as the suggested vocabulary, that is identified in the definition for that property. The suggested vocabularies are defined in section 6. The value of the property SHOULD be chosen from the suggested vocabulary but MAY be any other string value. Values that are not from the suggested vocabulary SHOULD be all lowercase (where lowercase is defined by the locality conventions) and SHOULD use hyphens instead of spaces or underscores as word separators.

A consumer that receives STIX content with one or more open-vocab terms not defined in the suggested vocabulary MAY ignore those values.

The JSON MTI serialization uses the JSON string type [RFC7159] when representing open-vocab.

Examples

Example using value from the suggested vocabulary. In this example the Indicator labels property is an open vocabulary and we are using one of the suggested vocabulary values.

{

  ...,

  "labels": ["malicious-activity"],

  ...

}

Example using a custom value. In this example, for the same Indicator labels property, we are not using a value in the suggested vocabulary.

{

  ...,

  "labels": ["pbx-fraud-activity"],

  ...

}

​2.10​ String

Type Name: string

The string data type represents a finite-length string of valid characters from the Unicode coded character set [ISO10646]. Unicode incorporates ASCII and the characters of many other international character sets.

The JSON MTI serialization uses the JSON string type [RFC7159], which mandates the UTF-8 encoding for supporting Unicode.

Examples

{

  ...

  "name": "The Black Vine Cyberespionage Group",

  ...

}

​2.11​ Timestamp

Type Name: timestamp

The timestamp type defines how dates and times are represented in STIX.

The JSON MTI serialization uses the JSON string type [RFC7159] when representing timestamp.

​2.11.1​ Requirements

Examples

{

  ...

  "created": "2016-01-20T12:31:12.123Z",

  ...

}



​3​ STIX™ Objects

This section outlines the common properties and behavior across all SDOs and SROs.

The JSON MTI serialization uses the JSON object type [RFC7159] when representing all STIX Objects.

​3.1​ Common Properties

Property Name

Type

Description

type (required)

string

The type property identifies the type of STIX Object. The value of the type property MUST be the name of one of the types of STIX Object defined in sections 2 and 3 of STIX™ Version 2.0. Part 2: STIX Objects (e.g., indicator) or the name of a custom object as defined by section 7.2.

id (required)

identifier

The id property universally and uniquely identifies this object. All objects with the same id are considered different versions of the same object.

Because the object type is part of the identifier, it is invalid for objects of different types to share the same id.

created_by_ref (optional)

identifier

The created_by_ref property specifies the ID of the Identity object that describes the entity that created this object.

If this attribute is omitted, the source of this information is undefined. This may be used by object creators who wish to remain anonymous.

created (required)

timestamp

The created property represents the time at which the first version of this object was created. The object creator can use the time it deems most appropriate as the time the object was created.

The created property MUST NOT be changed when creating a new version of the object.

The created timestamp MUST be precise to the nearest millisecond (exactly three digits after the decimal place in seconds).

See section 3.4 for further definition of versioning.

modified (required)

timestamp

The modified property represents the time that this particular version of the object was created. The object creator can use the time it deems most appropriate as the time this version of the object was modified. The value of the modified property for a given object version MUST be later than or equal to the value of the created property.

Object creators MUST set the modified property when creating a new version of an object.

The modified timestamp MUST be precise to the nearest millisecond (exactly three digits after the decimal place in seconds).

See section 3.4 for further definition of versioning.

revoked (optional)

boolean

The revoked property indicates whether the object has been revoked. Revoked objects are no longer considered valid by the object creator. Revoking an object is permanent; future versions of the object with this id MUST NOT be created. 

The default value of this property is false.

See section 3.4 for further definition of versioning.

labels (optional)

list of type string

The labels property specifies a set of classifications.

Each STIX Object can define a suggested vocabulary for the labels property. For example, the Indicator object, as defined in section 2.5 of STIX™ Version 2.0. Part 2: STIX Objects, uses the Indicator Label vocabulary as defined in section 6.5.

In some cases (generally, when a suggested vocabulary is defined) the labels property is then required for that specific SDO.

If a vocabulary is defined, items in this list SHOULD come from the vocabulary. Additional labels MAY be added beyond what is in the suggested vocabulary.

external_references

(optional)

list of type external-reference

The external_references property specifies a list of external references which refers to non-STIX information. This property is used to provide one or more URLs, descriptions, or IDs to records in other systems.

object_marking_refs (optional)

list of type identifier

The object_marking_refs property specifies a list of IDs of marking-definition objects that apply to this object.

See section 4 for further definition of data markings.

granular_markings (optional)

list of type granular-marking

The granular_markings property specifies a list of granular markings applied to this object.

See section 4 for further definition of data markings.

​3.2​ IDs and References

The id property universally and uniquely identifies an SDO, SRO, Bundle, or Marking Definition. It MUST meet the requirements of the identifier type (see section 2.5).

All STIX Objects (as well as Bundle and Marking Definition) use identifiers as defined by the identifier type. The identifier type is also used to define properties that are ID references to other constructs (such as the created_by_ref property in all STIX Objects). Resolving an ID reference is the process of identifying and obtaining the actual object referred to by the ID reference property. ID references resolve to an object when the value of the ID reference property (e.g., created_by_ref) is an exact match with the id property of another object. If a consumer has access to multiple versions of an object, the consumer SHOULD interpret any references to that object as referring to the latest version as defined in section 3.4. ID references can refer to objects to which the consumer/producer may not currently have. This specification does not address the implementation of ID reference resolution.

​3.3​ Object Creator

The object creator is the entity (e.g., system, organization, instance of a tool) that generates the id property for a given object. Object creators are represented as Identity objects. An embedded relationship to the Identity object representing the object creator MAY be captured in the created_by_ref property (or that property can be left blank, meaning the object creator is anonymous).

Entities that re-publish an object from another entity without making any changes to the object, and thus maintaining the original id, are not considered the object creator and MUST NOT change the created_by_ref property. An entity that accepts objects and republishes them with modifications, additions, or omissions MUST create a new id for the object. They are considered the object creator of the new object for purposes of versioning.

​3.4​ Versioning

Versioning is the mechanism that object creators use to update and revoke the STIX Objects that they create. This section describes the versioning process and normative rules for performing versioning and revocation. STIX Objects are versioned using the revoked, created, and modified properties. See the properties table in section 3.1 for full definitions and normative usage of those properties.

STIX Objects MAY be versioned in order to update, add, or remove information. A version of a STIX Object is identified uniquely by the combination of its id and modified properties. The first version of the object MUST have the same timestamp for the created and modified properties. More recent values of the modified property indicate later versions of the object. Implementations MUST consider the version of the STIX Object with the most recent modified value to be the most recent state of the object. For every new version of an object, the modified property MUST be updated to represent the time that the new version was created. If a consumer receives two objects that are different, but have the same id and modified timestamp, it is not defined how the consumer handles the objects. This specification does not address how implementations should handle versions of the object that are not current.

STIX Objects have a single object creator, the entity that generates the id for the object and creates the first version. The object creator may (but not necessarily will) be identified in the created_by_ref property of the object. Only the object creator is permitted to create new versions of a STIX Object. Producers other than the object creator MUST NOT create new versions of that object. If a producer other than the object creator wishes to create a new version, they MUST instead create a new object with a new id. They SHOULD additionally create a derived-from Relationship object to relate their new object to the original object that it was derived from.

Every representation (each time the object version is serialized and shared) of a version of an object (identified by the object's id and modified properties) MUST always have the same set of properties and the same values for each property. In order to change the value of any property, or to add or remove properties, the modified property MUST be updated with the time of the change to indicate a new version.

Objects can also be revoked, which means that they are no longer considered valid by the object creator. As with issuing a new version, only the object creator is permitted to revoke a STIX Object. A value of true in the revoked property indicates that an object (including the current version and all past versions) has been revoked. Revocation is permanent: once an object is marked as revoked, later versions of that object MUST NOT be created. Changing the revoked property to indicate that an object is revoked is an update to the object, and therefore its modified property MUST be updated at the same time. This specification does not address how implementations should handle revoked data.

​3.4.1​ Versioning Timestamps

There are two timestamp properties used to indicate when STIX Objects were created and modified: created and modified. The created property indicates the time the first version of the object was created. The modified property indicates the time the specific version of the object was created. The modified time MUST NOT be earlier than the created time. This specification does not address the specifics of how implementations should determine the value of the creation and modification times for use in the created and modified properties (e.g. one system might use when the object is first added to the local database as the creation time, while another might use the time when the object is first distributed as STIX).

​3.4.2​ New Version or New Object?

Eventually an implementation will encounter a case where a decision must be made regarding whether a change is a new version of an existing object or is different enough that it is a new object. This is generally considered a data quality problem and therefore this specification does not provide any normative text.

 

However, to assist implementers and promote consistency across implementations, some rules of thumb are provided. Any time a change indicates a material change to the meaning of the object, a new object with a different id should be used. A material change is any change that the object creator believes substantively changes the meaning of the object. As an example, an object creator might consider changing a Threat Actor from one country to another is a material change. These decisions are always made by the object creator. The object creator should also think about relationships to the object when deciding if a change is material. If the change would invalidate the usefulness of relationships to the object, then the change is considered material and a new object id should be used.

Examples

Example of a new version

One object creator has decided that the previous name they used for a SDO is incorrect. They consider that change as an update to the object.

Note: the IDs in the example below use a simplified format to help illustrate the changing IDs more clearly.

Step #

STIX Object

Object Creator Action

1

{

  "type": "example",

  "id": "example--1",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-01T06:13:14.000Z",

  "name": "attention",

  "description": "this is the description"

}

Original version of an object is created.

2

N/A, STIX is not involved in this step

Object creator changes the name in their internal database.

3

{

  "type": "example",

  "id": "example--1",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-08T03:43:44.000Z",

  "name": "Attention!",

  "description": "this is the description"

}

Object creator updates the modified property.

Example of derived object

One object creator has decided that the previous name they used for a SDO is incorrect. They consider that change fundamental to the meaning of the object and therefore revoke the object and issue a new one.

Step #

STIX Object

Object Creator Action

1

{

  "type": "example",

  "id": "example--1",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-01T06:13:14.000Z",

  "name": "attention",

  "description": "this is the description"

}

Original object created (via new id and setting created and modified to the same value).

2

N/A, STIX is not involved in this step

Object creator changes the name in their internal database.

3

{

  "type": "example",

  "id": "example--1",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-08T03:43:44.000Z",

  "name": "attention",

  "description": "this is the description",

  "revoked": true

}

Object creator revokes the existing object by setting revoked to true. The modified property is updated.

4

{

  "type": "example",

  "id": "example--2",

  "created": "2016-05-08T03:43:44.000Z",

  "modified": "2016-05-08T03:43:44.000Z",

  "name": "Something completely different",

  "description": "this is the description"

}

Object creator creates a new object (with a new id and setting created and modified to the same value).

5

{

  "type": "relationship",

  "id": "relationship--3",

  "created": "2016-05-08T03:43:44.000Z",

  "modified": "2016-05-08T03:43:44.000Z",

  "relationship_type": "derived-from",

  "source_ref": "example--1",

  "target_ref": "example--2"

}

(Optional) Object creator creates a new Relationship indicating that the new object is derived from the old object.

Example consumer workflow

This section describes an example workflow where a consumer receives multiple updates to a particular object. (In this example, the STIX Objects have been truncated for brevity.)

Step #

STIX Object

Recipient Action

1

{

  "type": "example",

  "id": "example--1",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-01T06:13:14.000Z"

}

Consumer stores example object because this is the first time they have seen the object.

2

{

  "type": "example",

  "id": "example--1",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-08T03:43:44.000Z"

}

Consumer updates example object because the received modified property is later than the object that is currently stored.

 

3

{

  "type": "example",

  "id": "example--1",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-06T06:23:45.000Z"

}

Consumer ignores this object because they already have a newer version of the object.

Note: consumer might choose to store meta-information about received objects, including versions that were received out-of-order. The consumer also may choose to store a copy for reference.

4

{

  "type": "example",

  "id": "example--1",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-11T06:41:21.000Z",

  "revoked": true

}

Consumer decides to delete example object, but keeps some metadata regarding the object.

5

{

  "type": "example",

  "id": "example--1",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-10T17:28:54.000Z"

}

Consumer ignores this object because they already have a newer version of the object (the revoked version).

Example object creator workflow

This section describes an example workflow where a object creator publishes multiple updates to a particular object. This scenario assumes a human using a STIX implementation. (In this example, the STIX Objects have been truncated for brevity.)

Step #

STIX Object

User Action

1

N/A – STIX is not involved in this scenario.

(Tools could choose to create and track STIX versions for internal changes, but it is not required by the specification.)

User clicks a create button in the user interface, creates a SDO, then clicks save. This action causes information to be stored in the product’s database.

 

2

{

  "type": "example",

  "id": "example--2",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-01T06:13:14.000Z"

}

The user clicks the “share” button, delivering the intelligence to sharing partners.

 

3

N/A – STIX is not involved in this scenario.

(Tools could choose to create and track STIX versions for internal changes, but it is not required by the specification.)

The user performs additional analysis within the STIX implementation, performing multiple modifications and saving their work multiple times.

4

{

  "type": "example",

  "id": "example--2",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-03T16:33:51.000Z"

}

The user, happy with the status of their work, decides to provide an update to some properties of the previously published object (not shown).

5

{

  "type": "example",

  "id": "example--2",

  "created": "2016-05-01T06:13:14.000Z",

  "modified": "2016-05-08T13:35:12.000Z",

  "revoked": true

}

The user receives lots of negative feedback regarding the quality of their work and decides to retract the object by pressing the “revoke” button.

​3.5​ Common Relationships

Each SDO has its own set of relationship types that are specified in the definition of that SDO. The following common relationship types are defined for all SDOs. See section 1.4.3 for more information about relationships.

Relationship Type

Source

Target

Description

derived-from

<STIX Domain Object>

<STIX Domain Object of same type>

The information in the target object is based on information from the source object.

derived-from is an explicit relationship between two separate objects and MUST NOT be used as a substitute for the versioning process defined in section 3.4.

duplicate-of

<STIX Domain Object>

<STIX Domain Object of same type>

The referenced source and target objects are semantically duplicates of each other.

This specification does not address whether the source or the target object is the duplicate object or what action, if any, a consumer should take when receiving an instance of this relationship.

As an example, a Campaign object from one organization could be marked as a duplicate-of a Campaign object from another organization if they both described the same campaign.

related-to

<STIX Domain Object>

<STIX Domain Object of any type>

Asserts a non-specific relationship between two SDOs. This relationship can be used when none of the other predefined relationships are appropriate.

As an example, a Malware object describing a piece of malware could be marked as a related-to a Tool if they are commonly used together. That relationship is not common enough to standardize on, but may be useful to some analysts.

​3.6​ Reserved Properties

This section defines property names that are reserved for future use in revisions of this document. The property names defined in this section MUST NOT be used for the name of any Custom Property.

Properties that are currently reserved across all STIX Objects are:

In addition, the following object names are reserved:



​4​ Data Markings

Data markings represent restrictions, permissions, and other guidance for how data can be used and shared. For example, data may be shared with the restriction that it must not be re-shared, or that it must be encrypted at rest. In STIX, data markings are specified using the marking-definition object. These definitions are applied to complete STIX Objects using object markings and to individual properties of STIX Objects via granular markings.

Some types of marking definitions or trust groups have rules about which markings override other markings or which markings can be additive to other markings. This specification does not define rules for how multiple markings applied to the same object or property should be interpreted.

​4.1​ Marking Definition

Type Name: marking-definition

The marking-definition object represents a specific marking. Data markings typically represent handling or sharing requirements for data, and are applied in the object_marking_refs and granular_markings properties on STIX Objects, which reference a list of IDs for marking-definition objects.

Two marking definition types are defined in this specification: TLP, to capture TLP markings, and Statement, to capture text marking statements. In addition, it is expected that the FIRST Information Exchange Policy (IEP) will be included in a future version once a machine-usable specification for it has been defined.

Unlike STIX Objects, Marking Definition objects cannot be versioned because it would allow for indirect changes to the markings on a STIX Object. For example, if a Statement marking is changed from "Reuse Allowed" to "Reuse Prohibited", all STIX Objects marked with that Statement marking would effectively have an updated marking without being updated themselves. Instead, a new Statement marking with the new text should be created and the marked objects updated to point to the new marking.

The JSON MTI serialization uses the JSON object type [RFC7159] when representing marking-definition.

​4.1.1​ Properties

Property Name

Type

Description

type (required)

string

The type property identifies the type of object. The value of this property MUST be marking-definition.

id (required)

identifier

The id property universally and uniquely identifies this Marking Definition.

Because the object type is part of the identifier, it is not possible for objects of different types to share the same id.

created_by_ref (optional)

identifier

The created_by_ref property specifies the ID of the identity object that describes the entity that created this Marking Definition.

If this attribute is omitted, the source of this information is undefined. This may be used by object creators who wish to remain anonymous.

created (required)

timestamp

The created property represents the time at which the Marking Definition was created. The object creator can use the time it deems most appropriate as the time the object was created.

external_references

(optional)

list of type external-reference

The external_references property specifies a list of external references which refers to non-STIX information. This property is used to provide one or more URLs, descriptions, or IDs to records in other systems.

object_marking_refs (optional)

list of type identifier

The object_marking_refs property specifies a list of IDs of marking-definitions that apply to this Marking Definition. This property MUST NOT contain any references to this Marking Definition object (i.e., it cannot contain any circular references).

Though uncommon, in some cases marking definitions themselves may be marked with sharing or handling guidance.

granular_markings (optional)

list of type granular-marking

The granular_markings property specifies a list of granular markings applied to this. This property MUST NOT contain any references to this Marking Definition object (i.e., it cannot contain any circular references).

Though uncommon, in some cases Marking Definitions themselves may be marked with sharing or handling guidance.

definition_type (required)

open-vocab

The definition_type property identifies the type of Marking Definition. The value of the definition_type property SHOULD be one of the types defined in the subsections below: statement or tlp (see sections 4.1.3 and 4.1.4)

definition (required)

<marking object>

The definition property contains the marking object itself (e.g., the TLP marking as defined in section 4.1.4, the Statement marking as defined in section 4.1.3, or some other marking definition defined elsewhere).

​4.1.2​ Relationships

Data Marking is not a STIX Object and MUST NOT have any SRO relationships to it or from it. This table lists the embedded relationships by property name along with their corresponding target.

Embedded Relationships

created_by_ref

identity

object_marking_refs

marking-definition

​4.1.3​ Statement Marking Object Type

The Statement marking type defines the representation of a textual marking statement (e.g., copyright, terms of use, etc.) in a definition. The value of the definition_type property MUST be statement when using this marking type. Statement markings are generally not machine-readable and this specification does not define any behavior or actions based on their values.

Content may be marked with multiple Statement marking types that do not override each other. In other words, the same content can be marked both with a statement saying "Copyright 2016" and a statement saying "Terms of use are ..." and both statements apply.

Property Name

Type

Description

statement (required)

string

A Statement (e.g., copyright, terms of use) applied to the content marked by this marking definition.

Examples

{

  "type": "marking-definition",

  "id": "marking-definition--34098fce-860f-48ae-8e50-ebd3cc5e41da",

  "created": "2016-08-01T00:00:00.000Z",

  "definition_type": "statement",

  "definition": {

    "statement": "Copyright 2016, Example Corp"

  }

}

​4.1.4​ TLP Marking Object Type

The TLP marking type defines how you would represent a Traffic Light Protocol (TLP) marking in a definition property. The value of the definition_type property MUST be tlp when using this marking type.

Property Name

Type

Description

tlp (required)

string

The TLP level [TLP] of the content marked by this marking definition, as defined in this section.

The following standard marking definitions MUST be used to reference or represent TLP markings. Other instances of tlp-marking MUST NOT be used (the only instances of TLP marking definitions permitted are those defined here).

white

{

  "type": "marking-definition",

  "id": "marking-definition--613f2e26-407d-48c7-9eca-b8e91df99dc9",

  "created": "2017-01-20T00:00:00.000Z",

  "definition_type": "tlp",

  "definition": {

    "tlp": "white"

  }

}

green

{

  "type": "marking-definition",

  "id": "marking-definition--34098fce-860f-48ae-8e50-ebd3cc5e41da",

  "created": "2017-01-20T00:00:00.000Z",

  "definition_type": "tlp",

  "definition": {

    "tlp": "green"

  }

}

amber

{

  "type": "marking-definition",

  "id": "marking-definition--f88d31f6-486f-44da-b317-01333bde0b82",

  "created": "2017-01-20T00:00:00.000Z",

  "definition_type": "tlp",

  "definition": {

    "tlp": "amber"

  }

}

red

{

  "type": "marking-definition",

  "id": "marking-definition--5e57c739-391a-4eb3-b6be-7d15ca92d5ed",

  "created": "2017-01-20T00:00:00.000Z",

  "definition_type": "tlp",

  "definition": {

    "tlp": "red"

  }

}

​4.2​ Object Markings

Object Markings apply data markings to an entire STIX Object or Marking Definition and all of its contents. Object Markings are specified as embedded relationships in the object_marking_refs property, which is an optional list of IDs for marking-definition objects. The referenced markings apply to that STIX Object or Marking Definition and all of its contents. Changes to the object_marking_refs property (and therefore the markings applied to the object) are treated the same as changes to any other properties on the object and follow the same rules for versioning.

Examples

This example marks the Indicator and all its properties with the Marking Definition referenced by the ID.

{

  "type": "indicator",

  "id": "indicator--b346b4b3-f4b7-4235-b659-f985f65f0009",

  ...

  "object_marking_refs": ["marking-definition--089a6ecb-cc15-43cc-9494-767639779123"],

  ...

}

​4.3​ Granular Markings

Whereas object markings apply to an entire STIX Object or Marking Definition and all its properties, granular markings allow data markings to be applied to individual portions of STIX Objects and Marking Definitions. Granular markings are specified in the granular_markings property, which is a list of granular-marking instances. Each of those instances contains a list of selectors to indicate what is marked and a reference to the marking-definition object to be applied. Granular markings can be used, for example, to indicate that the name property of an indicator should be handled as TLP:GREEN, the description property as TLP:AMBER, and the pattern property as TLP:RED.

​4.3.1​ Granular Marking Type

The granular-marking type defines how the marking-definition object referenced by the marking_ref property applies to a set of content identified by the list of selectors in the selectors property.

Property Name

Type

Description

marking_ref (required)

identifier

The marking_ref property specifies the ID of the marking-definition object that describes the marking.

selectors 

(required)

list of type string

The selectors property specifies a list of selectors for content contained within the STIX Object in which this property appears. Selectors MUST conform to the syntax defined in section 4.3.1.1.

The marking-definition referenced in the marking_ref property is applied to the content selected by the selectors in this list.

​4.3.1.1​ Selector Syntax

Selectors contained in the selectors list are strings that consist of multiple components that MUST be separated by the . character. Each component MUST be one of:

Selectors denote path traversals: the root of each selector is the STIX Object that the granular_markings property appears in. Starting from that root, for each component in the selector, properties and list items are traversed. When the complete list has been traversed, the value of the content is considered selected.

Selectors MUST refer to properties or list items that are actually present on the marked object.

As an example, consider the following STIX Object:

{

  "id": "vulnerability--ee916c28-c7a4-4d0d-ad56-a8d357f89fef",

  "created": "2016-02-14T00:00:00.000Z",

  "modified": "2016-02-14T00:00:00.000Z",

  "type": "vulnerability",

  "name": "CVE-2014-0160",

  "description": "The (1) TLS...",

  "external_references": [{

    "source_name": "cve",

    "external_id": "CVE-2014-0160"

  }],

  "labels": ["heartbleed", "has-logo"]

}

Valid selectors:

Invalid selectors:

This syntax is inspired by JSONPath [Goessner 2007] and is in fact a strict subset of allowable JSONPath expressions (with the exception that the '$' to indicate the root is implicit). Care should be taken when passing selectors to JSONPath evaluators to ensure that the root of the query is the individual STIX Object. It is expected, however, that selectors can be easily evaluated in programming languages that implement list and key/value mapping types (dictionaries, hashmaps, etc.) without resorting to an external library.

Examples

This example marks the description and labels properties with the single marking definition referenced in the list.

{

  ...

  "granular_markings": [

    {

      "marking_ref": "marking-definition--089a6ecb-cc15-43cc-9494-767639779123",

      "selectors": ["description", "labels"]

    }

  ],

  "description": "Some description",

  "name": "Some name",

  "labels": ["first", "second"]

}

​​ 



​5​ Bundle

Type Name: bundle

A Bundle is a collection of arbitrary STIX Objects and Marking Definitions grouped together in a single container. A Bundle does not have any semantic meaning and Objects are not considered related by virtue of being in the same Bundle.

Bundle is not STIX Object, so it does not have any of the Common Properties other than the type and id properties. Bundle is transient and implementations should not assume that other implementations will treat it as a persistent object.

The JSON MTI serialization uses the JSON object type [RFC7159] when representing bundle.

​5.1​ Properties

Property Name

Type

Description

type (required)

string

The type property identifies the type of object. The value of this property MUST be bundle.

id (required)

identifier

An identifier for this Bundle. The id property for the Bundle is designed to help tools that may need it for processing, but tools are not required to store or track it. Consuming tools should not rely on the presence of this property or the ability to refer to bundles by ID.

spec_version (required)

string

The version of the STIX specification used to represent the content in this Bundle. This enables non-TAXII transports or other transports without their own content identification mechanisms to know the version of STIX content.

The value of this property MUST be 2.0 for bundles containing STIX Objects defined in this specification.

objects (optional)

list of type <STIX Object> or marking-definition

Specifies a set of one or more STIX Objects. Objects in this list MUST be a STIX Object (SDO, SRO or Custom Object) or a Marking Definition object.

​5.2​ Relationships

Bundle is not a STIX Object and MUST NOT have any relationships to it or from it.

Examples

{

  "type": "bundle",

  "id": "bundle--5d0092c5-5f74-4287-9642-33f4c354e56d",

  "spec_version": "2.0",

  "objects": [

    {

      "type": "indicator",

      "id": "indicator--8e2e2d2b-17d4-4cbf-938f-98ee46b3cd3f",

      "created_by_ref": "identity--f431f809-377b-45e0-aa1c-6a4751cae5ff",

      "created": "2016-04-29T14:09:00.000Z",

      "modified": "2016-04-29T14:09:00.000Z",

      "object_marking_refs": ["marking-definition--089a6ecb-cc15-43cc-9494-767639779123"],

      "name": "Poison Ivy Malware",

      "description": "This file is part of Poison Ivy",

      "pattern": "[file:hashes.'SHA-256' = 'aec070645fe53ee3b3763059376134f058cc337247c978add178b6ccdfb0019f']"

    },

    {

      "type": "marking-definition",

      "id": "marking-definition--34098fce-860f-48ae-8e50-ebd3cc5e41da",

      "created": "2016-08-01T00:00:00.000Z",

      "definition_type": "tlp",

      "definition": {

        "tlp": "green"

      }

    }

  ]

}



​6​ Vocabularies

The following sections provide object-specific listings for each of the vocabularies referenced in the object description sections defined in STIX™ Version 2.0. Part 2: STIX Objects. STIX vocabularies, which all have type names ending in '-ov', are "open": they provide a listing of common and industry accepted terms as a guide to the user but do not limit the user to that defined list.

​6.1​ Attack Motivation

Vocabulary Name: attack-motivation-ov

The attack motivation vocabulary is currently used in the following SDOs:

Knowing a Threat Actor or Intrusion Set's motivation may allow an analyst or defender to better understand likely targets and behaviors.

Motivation shapes the intensity and the persistence of an attack. Threat Actors and Intrusion Sets usually act in a manner that reflects their underlying emotion or situation, and this informs defenders of the manner of attack. For example, a spy motivated by nationalism (ideology) likely has the patience to achieve long-term goals and work quietly for years, whereas a cyber-vandal out for notoriety can create an intense and attention-grabbing attack but may quickly lose interest and move on. Understanding these differences allows defenders to implement controls tailored to each type of attack for greatest efficiency.

This section including vocabulary items and their descriptions is based on the Threat Agent Motivations publication from Intel Corp in February 2015 [Casey 2015].

Vocabulary Summary

accidental, coercion, dominance, ideology, notoriety, organizational-gain, personal-gain, personal-satisfaction, revenge, unpredictable

Vocabulary Value

Description

accidental

A non-hostile actor whose benevolent or harmless intent inadvertently causes harm.

For example, a well-meaning and dedicated employee who through distraction or poor training unintentionally causes harm to his or her organization.

coercion

Being forced to act on someone else's behalf.  

Adversaries who are motivated by coercion are often forced through intimidation or blackmail to act illegally for someone else’s benefit. Unlike the other motivations, a coerced person does not act for personal gain, but out of fear of incurring a loss.

dominance

A desire to assert superiority over someone or something else.

Adversaries who are seeking dominance over a target are focused on using their power to force their target into submission or irrelevance. Dominance may be found with ideology in some state-sponsored attacks and with notoriety in some cyber vandalism based attacks.

ideology

A passion to express a set of ideas, beliefs, and values that may shape and drive harmful and illegal acts.

Adversaries who act for ideological reasons (e.g., political, religious, human rights, environmental, desire to cause chaos/anarchy, etc.) are not usually motivated primarily by the desire for profit; they are acting on their own sense of morality, justice, or political loyalty.

For example, an activist group may sabotage a company’s equipment because they believe the company is harming the environment.

notoriety

Seeking prestige or to become well known through some activity.

Adversaries motivated by notoriety are often seeking either personal validation or respect within a community and staying covert is not a priority. In fact one of the main goals is to garner the respect of their target audience.

organizational-gain

Seeking advantage over a competing organization, including a military organization.

Adversaries motivated by increased profit or other gains through an unfairly obtained competitive advantage are often seeking theft of intellectual property, business processes, or supply chain agreements and thus accelerating their position in a market or capability.

personal-gain

The desire to improve one’s own financial status.

Adversaries motivated by a selfish desire for personal gain are often out for gains that come from financial fraud, hacking for hire, or intellectual property theft.  

While a Threat Actor or Intrusion Set may be seeking personal gain this does not mean they are acting alone. Individuals can band together solely to maximize their own personal profits.

personal-satisfaction

A desire to satisfy a strictly personal goal, including curiosity, thrill-seeking, amusement, etc.

Threat Actors or Intrusion Set driven by personal satisfaction may incidentally receive some other gain from their actions, such as a profit, but their primary motivation is to gratify a personal, emotional need. Individuals can band together with others toward a mutual, but not necessarily organizational, objective.

revenge

A desire to avenge perceived wrongs through harmful actions such as sabotage, violence, theft, fraud, or embarrassing certain individuals or the organization.

A disgruntled Threat Actor or Intrusion Set seeking revenge can include current or former employees, who may have extensive knowledge to leverage when conducting attacks. Individuals can band together with others if the individual believes that doing so will enable them to cause more harm.

unpredictable

Acting without identifiable reason or purpose and creating unpredictable events.

Unpredictable is not a miscellaneous or default category. Unpredictable means a truly random and likely bizarre event, which seems to have no logical purpose to the victims.

​6.2​ Attack Resource Level

Vocabulary Name: attack-resource-level-ov

The attack resource level vocabulary is currently used in the following SDO(s):

Attack Resource Level is an open vocabulary that captures the general level of resources that a threat actor, intrusion set, or campaign might have access to. It ranges from individual, a person acting alone, to government, the resources of a national government.

This section including vocabulary items and their descriptions is based on the Threat Agent Library publication from Intel Corp in September 2007 [Casey 2007].

Vocabulary Summary

individual, club, contest, team, organization, government

Vocabulary Value

Description

individual

Resources limited to the average individual; Threat Actor acts independently.

club

Members interact on a social and volunteer basis, often with little personal interest in the specific target. An example might be a core group of unrelated activists who regularly exchange tips on a particular blog. Group persists long term.

contest

A short-lived and perhaps anonymous interaction that concludes when the participants have achieved a single goal. For example, people who break into systems just for thrills or prestige may hold a contest to see who can break into a specific target first. It also includes announced "operations" to achieve a specific goal, such as the original "OpIsrael" call for volunteers to disrupt all of Israel's Internet functions for a day.

team

A formally organized group with a leader, typically motivated by a specific goal and organized around that goal. Group persists long term and typically operates within a single geography.

organization

Larger and better resourced than a team; typically a company or crime syndicate. Usually operates in multiple geographic areas and persists long term.

government

Controls public assets and functions within a jurisdiction; very well resourced and persists long term.

​6.3​ Hashing Algorithm Vocabulary

Vocabulary Name: hash-algorithm-ov

An open vocabulary of hashing algorithms.

When specifying a hashing algorithm not already defined within the hash-algorithm-ov, wherever an authoritative name for a hashing algorithm name is defined, it should be used as the value. In cases where no authoritative name exists and/or where there is variance in the naming of a particular hashing algorithm, producers should exercise their best judgement.

                                                                 

Vocabulary Summary

MD5, MD6, RIPEMD-160, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, SHA3-224, SHA3-256, SHA3-384, SHA3-512, SSDEEP, WHIRLPOOL

Vocabulary Value

Description

MD5

Specifies the MD5 message digest algorithm. The corresponding hash string for this value MUST be a valid MD5 message digest as defined in [RFC 1321].

MD6

Specifies the MD6 message digest algorithm. The corresponding hash string for this value MUST be a valid MD6 message digest as defined in the [MD6] proposal.

RIPEMD-160

Specifies the RIPEMD­-160 (R​ACE​ Integrity Primitives Evaluation Message Digest)​ cryptographic hash function. The corresponding hash string for this value MUST be a valid RIPEMD-160 message digest as defined in the [RIPEMD-160] specification.

SHA-1

Specifies the SHA­-1 (secure-­hash algorithm 1) cryptographic hash function. The corresponding hash string for this value MUST be a valid SHA-1 message digest as defined in [RFC 3174].

SHA-224

Specifies the SHA-­224 cryptographic hash function (part of the SHA­2 family). The corresponding hash string for this value MUST be a valid SHA-224 message digest as defined in [RFC 6234].

SHA-256

Specifies the SHA-­256 cryptographic hash function (part of the SHA­2 family). The corresponding hash string for this value MUST be a valid SHA-256 message digest as defined in [RFC 6234].

SHA-384

Specifies the SHA-­384 cryptographic hash function (part of the SHA­2 family). The corresponding hash string for this value MUST be a valid SHA-384 message digest as defined in [RFC 6234].

SHA-512

Specifies the SHA-­512 cryptographic hash function (part of the SHA­2 family). The corresponding hash string for this value MUST be a valid SHA-512 message digest as defined in [RFC 6234].

SHA3-224

Specifies the SHA3-224 cryptographic hash function. The corresponding hash string for this value MUST be a valid SHA3-224 message digest as defined in [FIPS202].

SHA3-256

Specifies the SHA3-256 cryptographic hash function. The corresponding hash string for this value MUST be a valid SHA3-256 message digest as defined in [FIPS202].

SHA3-384

Specifies the SHA3-384 cryptographic hash function. The corresponding hash string for this value MUST be a valid SHA3-384 message digest as defined in [FIPS202].

SHA3-512

Specifies the SHA3-512 cryptographic hash function. The corresponding hash string for this value MUST be a valid SHA3-512 message digest as defined in [FIPS202].

ssdeep

Specifies the ssdeep fuzzy hashing algorithm. The corresponding hash string for this value MUST be a valid piecewise hash as defined in the [SSDEEP] specification.

WHIRLPOOL

Specifies the whirlpool cryptographic hash function. The corresponding hash string for this value MUST be a valid WHIRLPOOL message digest as defined in [ISO10118].

​6.4​ Identity Class

Vocabulary Name: identity-class-ov

The identity class vocabulary is currently used in the following SDO(s):

This vocabulary describes the type of entity that the Identity represents: whether it describes an organization, group, individual, or class.

Vocabulary Summary

individual, group, organization, class, unknown

Vocabulary Value

Description

individual

A single person.

group

An informal collection of people, without formal governance, such as a distributed hacker group.

organization

A formal organization of people, with governance, such as a company or country.

class

A class of entities, such as all hospitals, all Europeans, or the Domain Administrators in a system.

unknown

It is unknown whether the classification is individual, group, organization, or class.

​6.5​ Indicator Label

Vocabulary Name: indicator-label-ov

The indicator label vocabulary is currently used in the following SDO(s):

Indicator labels is an open vocabulary used to categorize Indicators. It is intended to be high-level to promote consistent practices. Indicator labels should not be used to capture information that can be better captured via related Malware or Attack Pattern objects. It is better to link an Indicator to a Malware object describing Poison Ivy rather than simply labeling it with "poison-ivy".

Vocabulary Summary

anomalous-activity, anonymization, benign, compromised, malicious-activity, attribution

Vocabulary Value

Description

anomalous-activity

Unexpected, or unusual activity that may not necessarily be malicious or indicate compromise. This type of activity may include reconnaissance-like behavior such as port scans or version identification, network behavior anomalies, and asset and/or user behavioral anomalies.

anonymization

Suspected anonymization tools or infrastructure (proxy, TOR, VPN, etc.).

benign

Activity that is not suspicious or malicious in and of itself, but when combined with other activity may indicate suspicious or malicious behavior.

compromised

Assets that are suspected to be compromised.

malicious-activity

Patterns of suspected malicious objects and/or activity.

attribution

Patterns of behavior that indicate attribution to a particular Threat Actor or Campaign.

​6.6​ Industry Sector

Vocabulary Name: industry-sector-ov

The industry sector vocabulary is currently used in the following SDO(s):

Industry sector is an open vocabulary that describes industrial and commercial sectors. It is intended to be holistic; it has been derived from several other lists and is not limited to "critical infrastructure" sectors.

Vocabulary Summary

agriculture, aerospace, automotive, communications, construction, defence, education, energy, entertainment, financial-services, government-national, government-regional, government-local, government-public-services, healthcare, hospitality-leisure, infrastructure, insurance, manufacturing, mining, non-profit, pharmaceuticals, retail, technology, telecommunications, transportation, utilities

Vocabulary Value

Description

agriculture

aerospace

automotive

communications

construction

defence

education

energy

entertainment

financial-services

government-national

government-regional

government-local

government-public-services

emergency services, sanitation

healthcare

hospitality-leisure

infrastructure

insurance

manufacturing

mining

non-profit

pharmaceuticals

retail

technology

telecommunications

transportation

utilities

​6.7​ Malware Label

Vocabulary Name: malware-label-ov

The malware label vocabulary is currently used in the following SDO(s):

Malware label is an open vocabulary that represents different types and functions of malware. Malware labels are not mutually exclusive; a malware instance can be both spyware and a screen capture tool.

Vocabulary Summary

adware, backdoor, bot, ddos, dropper, exploit-kit, keylogger, ransomware, remote-access-trojan, resource-exploitation, rogue-security-software, rootkit, screen-capture, spyware, trojan, virus, worm

Vocabulary Value

Description

adware

Any software that is funded by advertising. Adware may also gather sensitive user information from a system.

backdoor

A malicious program that allows an attacker to perform actions on a remote system, such as transferring files, acquiring passwords, or executing arbitrary commands [Mell2005].

bot

A program that resides on an infected system, communicating with and forming part of a botnet. The bot may be implanted by a worm or Trojan, which opens a backdoor. The bot then monitors the backdoor for further instructions.

ddos

A tool used to perform a distributed denial of service attack.

dropper

A type of trojan that deposits an enclosed payload (generally, other malware) onto the target computer.

exploit-kit

A software toolkit to target common vulnerabilities.

keylogger

A type of malware that surreptitiously monitors keystrokes and either records them for later retrieval or sends them back to a central collection point.

ransomware

A type of malware that encrypts files on a victim's system, demanding payment of ransom in return for the access codes required to unlock files.

remote-access-trojan

A remote access trojan program (or RAT), is a trojan horse capable of controlling a machine through commands issued by a remote attacker.

resource-exploitation

A type of malware that steals a system's resources (e.g., CPU cycles), such as a bitcoin miner.

rogue-security-software

A fake security product that demands money to clean phony infections.

rootkit

A type of malware that hides its files or processes from normal methods of monitoring in order to conceal its presence and activities. Rootkits can operate at a number of levels, from the application level  simply replacing or adjusting the settings of system software to prevent the display of certain information  through hooking certain functions or inserting modules or drivers into the operating system kernel, to the deeper level of firmware or virtualization rootkits, which are activated before the operating system and thus even harder to detect while the system is running.

screen-capture

A type of malware used to capture images from the target systems screen, used for exfiltration and command and control.

spyware

Software that gathers information on a user's system without their knowledge and sends it to another party. Spyware is generally used to track activities for the purpose of delivering advertising.

trojan

Any malicious computer program which is used to hack into a computer by misleading users of its true intent.

virus

A malicious computer program that replicates by reproducing itself or infecting other programs by modifying them.

worm

A self-replicating, self-contained program that usually executes itself without user intervention.

​6.8​ Report Label

Vocabulary Name: report-label-ov

The report label vocabulary is currently used in the following SDO(s):

Report label is an open vocabulary to describe the primary purpose or subject of a report. For example, a report that contains malware and indicators for that malware should have a report label of malware to capture that the malware is the primary purpose. Report labels are not mutually exclusive: a Report can be both a malware report and a tool report. Just because a report contains objects of a type does not mean that the report should include that label.  If the objects are there to simply provide evidence or context for other objects, it is not necessary to include them in the label.

Vocabulary Summary

threat-report, attack-pattern, campaign, identity, indicator, malware, observed-data, threat-actor, tool, vulnerability

Vocabulary Value

Description

threat-report

Report subject is a broad characterization of a threat across multiple facets.

attack-pattern

Report subject is a characterization of one or more attack patterns and related information.

campaign

Report subject is a characterization of one or more campaigns and related information.

identity

Report subject is a characterization of one or more identities and related information.

indicator

Report subject is a characterization of one or more indicators and related information.

intrusion-set

Report subject is a characterization of one or more intrusion sets and related information.

malware

Report subject is a characterization of one or more malware instances and related information.

observed-data

Report subject is a characterization of observed data and related information.

threat-actor

Report subject is a characterization of one or more threat actors and related information.

tool

Report subject is a characterization of one or more tools and related information.

vulnerability

Report subject is a characterization of one or more vulnerabilities and related information.

​6.9​ Threat Actor Label

Vocabulary Name: threat-actor-label-ov

The threat actor label vocabulary is currently used in the following SDO(s):

Threat actor label is an open vocabulary used to describe what type of threat actor the individual or group is. For example, some threat actors are competitors who try to steal information, while others are activists who act in support of a social or political cause. Actor labels are not mutually exclusive: a threat actor can be both a disgruntled insider and a spy. [Casey 2007])

Vocabulary Summary

activist, competitor, crime-syndicate, criminal, hacker, insider-accidental, insider-disgruntled, nation-state, sensationalist, spy, terrorist

Vocabulary Value

Description

activist

Highly motivated, potentially destructive supporter of a social or political cause (e.g., trade, labor, environment, etc.) that attempts to disrupt an organization's business model or damage their image.

This category includes actors sometimes referred to as anarchists, cyber vandals, extremists, and hacktivists.

competitor

An organization that competes in the same economic marketplace.

 

The goal of a competitor is to gain an advantage in business with respect to the rival organization it targets. It usually does this by copying intellectual property, trade secrets, acquisition strategies, or other technical or business data from a rival organization with the intention of using the data to bolster its own assets and market position.  

crime-syndicate

An enterprise organized to conduct significant, large-scale criminal activity for profit.

 

Crime syndicates, also known as organized crime, are generally large, well-resourced groups that operate to create profit from all types of crime.

criminal

Individual who commits computer crimes, often for personal financial gain and often involves the theft of something valuable.

 

Intellectual property theft, extortion via ransomware, and physical destruction are common examples. A criminal as defined here refers to those acting individually or in very small or informal groups. For sophisticated organized criminal activity, see the crime syndicate descriptor.

hacker

An individual that tends to break into networks for the thrill or the challenge of doing so.

Hackers may use advanced skills or simple attack scripts they have downloaded.

insider-accidental

A non-hostile insider who unintentionally exposes the organization to harm.

 

“Insider” in this context includes any person extended internal trust, such as regular employees, contractors, consultants, and temporary workers.

insider-disgruntled

Current or former insiders who seek revengeful and harmful retaliation for perceived wrongs.

 

“Insider” in this context includes any person extended internal trust, such as regular employees, contractors, consultants, and temporary workers.

 

Disgruntled threat actors may have extensive knowledge that can be leveraged when conducting attacks and can take any number of actions including sabotage, violence, theft, fraud, espionage, or embarrassing individuals or the organization.

nation-state

Entities who work for the government or military of a nation state or who work at their direction.

These actors typically have access to significant support, resources, training, and tools and are capable of designing and executing very sophisticated and effective Intrusion Sets and Campaigns.

sensationalist

Seeks to cause embarrassment and brand damage by exposing sensitive information in a manner designed to cause a public relations crisis.

 

A sensationalist may be an individual or small group of people motivated primarily by a need for notoriety. Unlike the activist, the sensationalist generally has no political goal, and is not using bad PR to influence the target to change its behavior or business practices.

spy

Secretly collects sensitive information for use, dissemination, or sale.

 

Traditional spies (governmental and industrial) are part of a well-resourced intelligence organization and are capable of very sophisticated clandestine operations. However, insiders such as employees or consultants acting as spies can be just as effective and damaging, even when their activities are largely opportunistic and not part of an overall campaign.

terrorist

Uses extreme violence to advance a social or political agenda as well as monetary crimes to support its activities.

 

In this context a terrorist refers to individuals who target noncombatants with violence to send a message of fear far beyond the actual events. They may act independently or as part of a terrorist organization.

Terrorist organizations must typically raise much of their operating budget through criminal activity, which often occurs online. Terrorists are also often adept at using and covertly manipulating social media for both recruitment and impact.

​6.10​ Threat Actor Role

Vocabulary Name: threat-actor-role-ov

The threat actor role vocabulary is currently used in the following SDO(s):

Threat actor role is an open vocabulary that is used to describe the different roles that a threat actor can play. For example, some threat actors author malware or operate botnets while other actors actually carry out attacks directly.

Threat actor roles are not mutually exclusive. For example, an actor can be both a financial backer for attacks and also direct attacks.

Vocabulary Summary

agent, director, independent, infrastructure-architect, infrastructure-operator, malware-author, sponsor

Vocabulary Value

Description

agent

Threat actor executes attacks either on behalf of themselves or at the direction of someone else.

director

The threat actor who directs the activities, goals, and objectives of the malicious activities.

independent

A threat actor acting by themselves.

infrastructure-architect

Someone who designs the battle space.

infrastructure-operator

The threat actor who provides and supports the attack infrastructure that is used to deliver the attack (botnet providers, cloud services, etc.).

malware-author

The threat actor who authors malware or other malicious tools.

sponsor

The threat actor who funds the malicious activities.

​6.11​ Threat Actor Sophistication

Vocabulary Name: threat-actor-sophistication-ov

Threat actor sophistication vocabulary is currently used in the following SDO(s):

Threat actor sophistication vocabulary captures the skill level of a threat actor. It ranges from "none", which describes a complete novice, to "strategic", which describes an attacker who is able to influence supply chains to introduce vulnerabilities. This vocabulary is separate from resource level because an innovative, highly-skilled threat actor may have access to very few resources while a minimal-level actor might have the resources of an organized crime ring.

Vocabulary Summary

none, minimal, intermediate, advanced, expert, innovator, strategic

Vocabulary Value

Description

none

Can carry out random acts of disruption or destruction by running tools they do not understand. Actors in this category have average computer skills.

Example Roles: Average User

These actors:

  • can not launch targeted attacks

minimal

Can minimally use existing and frequently well known and easy-to-find techniques and programs or scripts to search for and exploit weaknesses in other computers. Commonly referred to as a script-kiddie.

These actors rely on others to develop the malicious tools, delivery mechanisms, and execution strategy and often do not fully understand the tool they are using or how they work. They also lack the ability to conduct their own reconnaissance and targeting research.

Example Roles: Script-Kiddie

These actors:

  • attack known weaknesses;
  • use well known scripts and tools; and
  • have minimal knowledge of the tools.

intermediate

Can proficiently use existing attack frameworks and toolkits to search for and exploit vulnerabilities in computers or systems. Actors in this category have computer skills equivalent to an IT professional and typically have a working knowledge of networks, operating systems, and possibly even defensive techniques and will typically exhibit some operational security.

These actors rely others to develop the malicious tools and delivery mechanisms, but are able to plan their own execution strategy. They are proficient in the tools they are using and how they work and can even make minimal modifications as needed.

Example Roles: Toolkit User

These actors:

  • attack known vulnerabilities;
  • use attack frameworks and toolkits; and
  • have proficient knowledge of the tools.

advanced

Can develop their own tools or scripts from publicly known vulnerabilities to target systems and users. Actors in this category are very adept at IT systems and have a background in software development along with a solid understanding of defensive techniques and operational security.

These actors rely on others to find and identify weaknesses and vulnerabilities in systems, but are able to create their own tools, delivery mechanisms, and execution strategies.

Example Roles: Toolkit Developer

These actors:

  • attack known vulnerabilities;
  • can create their own tools; and
  • have proficient knowledge of the tools.

expert

Can focus on the discovery and use of unknown malicious code, are is adept at installing user and kernel mode rootkits, frequently use data mining tools, target corporate executives and key users (government and industry) for the purpose of stealing personal and corporate data. Actors in this category are very adept at IT systems and software development and are experts with security systems, defensive techniques, attack methods, and operational security.

Example Roles: Vulnerability Researcher, Reverse Engineer, Threat Researcher, Malware Creator

These actors:

  • attack unknown and known vulnerabilities;
  • can create their own tools from scratch; and
  • have proficient knowledge of the tools.

innovator

Typically criminal or state actors who are organized, highly technical, proficient, well-funded professionals working in teams to discover new vulnerabilities and develop exploits.

Demonstrates sophisticated capability. An innovator has the ability to create and script unique programs and codes targeting virtually any form of technology. At this level, this actor has a deep knowledge of networks, operating systems, programming languages, firmware, and infrastructure topologies and will demonstrate operational security when conducting his activities. Innovators are largely responsible for the discovery of 0-day vulnerabilities and the development of new attack techniques.

Example Roles: Toolkit Innovator, 0-Day Exploit Author

These actors:

  • attack unknown and known vulnerabilities;
  • create attacks against 0-Day exploits from scratch; and
  • create new and innovative attacks and toolkits.

strategic

State actors who create vulnerabilities through an active program to “influence” commercial products and services during design, development or manufacturing, or with the ability to impact products while in the supply chain to enable exploitation of networks and systems of interest.

These actors:

  • can create or use entire supply chains to launch an attack;
  • can create and design attacks for any systems, software package, or device; and
  • are responsible for APT-level attacks.

​6.12​ Tool Label

Vocabulary Name: tool-label-ov

The tool label vocabulary is currently used in the following SDO(s):

Tool labels describe the categories of tools that can be used to perform attacks.

Vocabulary Summary

denial-of-service, exploitation, information-gathering, network-capture, credential-exploitation, remote-access, vulnerability-scanning

Vocabulary Value

Description

denial-of-service

Tools used to perform denial of service attacks or DDoS attacks, such as Low Orbit Ion Cannon (LOIC) and DHCPig.

exploitation

Tools used to exploit software and systems, such as sqlmap and Metasploit.

information-gathering

Tools used to enumerate system and network information, e.g., NMAP.

network-capture

Tools used to capture network traffic, such as Wireshark and Kismet.

credential-exploitation

Tools used to crack password databases or otherwise exploit/discover credentials, either locally or remotely, such as John the Ripper and NCrack.

remote-access

Tools used to access machines remotely, such as VNC and Remote Desktop.

vulnerability-scanning

Tools used to scan systems and networks for vulnerabilities, e.g., Nessus.



​7​ Customizing STIX™

There are two primary means to customize STIX: Custom Properties, and Custom Objects. Custom Properties provides a mechanism and requirements for adding properties not defined by this specification to existing STIX Objects. Custom Objects, on the other hand, provides a mechanism and requirements to create custom STIX Objects (objects not defined by this specification).

A consumer that receives a STIX document containing Custom Properties or Objects it does not understand MAY refuse to process the document or MAY ignore those properties or objects and continue processing the document.

Producers of STIX documents that contain Custom Properties or Objects should recognize that consumers may not understand them and may ignore them. Producers should define any Custom Properties and Objects they use, along with any rules for processing them, and make these definitions and rules accessible to any potential consumers. This specification does not specify a process for doing this.

​7.1​ Custom Properties

There will be cases where certain information exchanges can be improved by adding properties that are neither specified nor reserved in this document; these properties are called Custom Properties. This section provides guidance and requirements for how producers can use Custom Properties and how consumers should interpret them in order to extend STIX in an interoperable manner.

​7.1.1​ Requirements

Examples

{

  ...,

  "x_acme_org_confidence": 10,

  "x_acme_org_scoring": {

    "impact": "high",

    "probability": "low"

  },

  ...

}

​7.2​ Custom Objects

There will be cases where certain information exchanges can be improved by adding objects that are not specified nor reserved in this document; these objects are called Custom Objects. This section provides guidance and requirements for how producers can use Custom Objects and how consumers should interpret them in order to extend STIX in an interoperable manner.

​7.2.1​ Requirements

Examples

{

  "type": "bundle",

  "id": "bundle--f37aa79d-f5f5-4af7-874b-734d32c08c10",

  "spec_version": "2.0",

  "custom_objects": [

    {

      "type": "x-example-com-customobject",

      "id": "x-example-com-customobject--4527e5de-8572-446a-a57a-706f15467461",

      "created": "2016-08-01T00:00:00.000Z",

      "modified": "2016-08-01T00:00:00.000Z",

      "some_custom_stuff": 14,

      "other_custom_stuff": "hello"

    }

  ]

}



​8​ Conformance

​8.1​ Producers and Consumers

A "STIX 2.0 Producer" is any software that creates STIX 2.0 content and conforms to the following normative requirements:

  1. It MUST be able to create content encoded as JSON.
  2. All properties marked required in the property table for the STIX Object or type MUST be present in the created content.
  3. All properties MUST conform to the data type and normative requirements for that property.
  4. It MUST support at least one STIX Object per the Conformance section in STIX™ Version 2.0. Part 2: STIX Objects.
  5. It MUST support all features listed in section 8.2, Mandatory Features.
  6. It MAY support any features listed in section 8.3, Optional Features. Software supporting an optional feature MUST comply with the normative requirements of that feature.
  7. It MUST support JSON as a serialization format and MAY support serializations other than JSON.

A "STIX 2.0 Consumer" is any software that consumes STIX 2.0 content and conforms to the following normative requirements:

  1. It MUST support parsing all required properties for the content that it consumes.
  2. It MUST support all features listed in section 8.2, Mandatory Features.
  3. It MAY support any features listed in section 8.3, Optional Features. Software supporting an optional feature MUST comply with the normative requirements of that feature.
  4. It MUST support JSON as a serialization format and MAY support serializations other than JSON.

​8.2​ Mandatory Features

​8.2.1​ Versioning

A STIX 2.0 Producer or STIX 2.0 Consumer MUST support versioning by following the normative requirements listed in section 3.4.

​8.3​ Optional Features

​8.3.1​ Object-Level Data Markings

A STIX 2.0 Producer or STIX 2.0 Consumer MAY support "Object-Level Data Markings". Software claiming to support "Object-Level Data Markings" MUST follow the normative requirements listed in sections 4.1 and 4.2.

​8.3.2​ Granular Data Markings

A STIX 2.0 Producer or STIX 2.0 Consumer MAY support "Granular Data Markings". Software claiming to support "Granular Data Markings" MUST follow the normative requirements listed in sections 4.1 and 4.3.

​8.3.3​ Custom Properties

A STIX 2.0 Producer or STIX 2.0 Consumer MAY support "Custom Properties". Software claiming to support "Custom Properties" MUST follow the normative requirements listed in section 7.1.

​8.3.4​ Custom Objects

A STIX 2.0 Producer or STIX 2.0 Consumer MAY support "Custom Objects". Software claiming to support "Custom Objects" MUST follow the normative requirements listed in section 7.2.



​Appendix A. Glossary

CAPEC - Common Attack Pattern Enumeration and Classification

Consumer - Any entity that receives STIX content

CTI - Cyber Threat Intelligence

Embedded Relationship - A link (an "edge" in a graph) between one STIX Object and another represented as a property on one object containing the ID of another object

Entity - Anything that has a separately identifiable existence (e.g., organization, person, group, etc.)

IEP - FIRST (Forum of Incident Response and Security Teams) Information Exchange Policy

Instance - A single occurrence of a STIX object version

MTI - Mandatory To Implement

MVP - Minimally Viable Product

Object Creator - The entity that created or updated a STIX object (see section 3.3)

Object Representation - An instance of an object version that is serialized as STIX

Producer - Any entity that distributes STIX content, including object creators as well as those passing along existing content

SDO - STIX Domain Object (a "node" in a graph)

SRO - STIX Relationship Object (one mechanism to represent an "edge" in a graph)

STIX - Structured Threat Information Expression

STIX Content - STIX documents, including STIX Objects, STIX Objects grouped as bundles, etc.

STIX Object - A STIX Domain Object (SDO) or STIX Relationship Object (SRO)

STIX Relationship - A link (an "edge" in a graph) between two STIX Objects represented by either an SRO or an embedded relationship

TAXII - An application layer protocol for the communication of cyber threat information

TLP - Traffic Light Protocol

TTP - Tactic, technique, or procedure; behaviors and resources that attackers use to carry out their attacks



​Appendix B. Acknowledgments

STIX Subcommittee Chairs:

Sarah Kelley, Center for Internet Security (CIS)

John Wunder, MITRE Corporation

 

Cyber Observable Subcommittee Chairs:

Trey Darley, Kingfisher Operations, sprl

Ivan Kirillov, MITRE Corporation

 

Special Thanks:

Substantial contributions to this specification from the following individuals are gratefully acknowledged:

 

Sarah Kelley, Center for Internet Security (CIS)

Terry MacDonald, Cosive

Jane Ginn, Cyber Threat Intelligence Network, Inc. (CTIN)

Richard Struse, DHS Office of Cybersecurity and Communications

Iain Brown, GDS

Jason Keirstead, IBM

Tim Casey, Intel

Trey Darley, Kingfisher Operations, sprl

Allan Thomson, LookingGlass Cyber

Greg Back, MITRE Corporation

Ivan Kirillov, MITRE Corporation

Jon Baker, MITRE Corporation

John Wunder, MITRE Corporation

Sean Barnum, MITRE Corporation

Richard Piazza, MITRE Corporation

Christian Hunt, New Context Services, Inc.

John-Mark Gurney, New Context Services, Inc.

Aharon Chernin, Perch

Dave Cridland, Surevine

Bret Jordan, Symantec Corp.

Participants:

The following individuals were members of the OASIS CTI Technical Committee during the creation of this specification and their contributions are gratefully acknowledged:

David Crawford, Aetna

Marcos Orallo, Airbus Group SAS

Roman Fiedler, AIT Austrian Institute of Technology

Florian Skopik, AIT Austrian Institute of Technology

Russell Spitler, AlienVault

Ryan Clough, Anomali

Nicholas Hayden, Anomali

Wei Huang, Anomali

Angela Nichols, Anomali

Hugh Njemanze, Anomali

Katie Pelusi, Anomali

Dean Thompson, Australia and New Zealand Banking Group (ANZ Bank)

Alexander Foley, Bank of America

Sounil Yu, Bank of America

Vicky Laurens, Bank of Montreal

Humphrey Christian, Bay Dynamics

Ryan Stolte, Bay Dynamics

Alexandre Dulaunoy, CIRCL

Andras Iklody, CIRCL

Rapha‘l Vinot, CIRCL

Sarah Kelley, CIS

Syam Appala, Cisco Systems

Ted Bedwell, Cisco Systems

David McGrew, Cisco Systems

Mark-David McLaughlin, Cisco Systems

Pavan Reddy, Cisco Systems

Omar Santos, Cisco Systems

Jyoti Verma, Cisco Systems

Doug DePeppe, Cyber Threat Intelligence Network, Inc. (CTIN)

Jane Ginn, Cyber Threat Intelligence Network, Inc. (CTIN)

Ben Othman, Cyber Threat Intelligence Network, Inc. (CTIN)

Jeff Odom, Dell

Sreejith Padmajadevi, Dell

Ravi Sharda, Dell

Will Urbanski, Dell

Sean Sobieraj, DHS Office of Cybersecurity and Communications (CS&C)

Richard Struse, DHS Office of Cybersecurity and Communications (CS&C)

Marlon Taylor, DHS Office of Cybersecurity and Communications (CS&C)

Jens Aabol, Difi-Agency for Public Management and eGovernment

Wouter Bolsterlee, EclecticIQ

Marko Dragoljevic, EclecticIQ

Oliver Gheorghe, EclecticIQ

Joep Gommers, EclecticIQ

Sergey Polzunov, EclecticIQ

Rutger Prins, EclecticIQ

Andrei S”rghi, EclecticIQ

Raymon van der Velde, EclecticIQ

Ben Sooter, Electric Power Research Institute (EPRI)

Chris Ricard, Financial Services Information Sharing and Analysis Center (FS-ISAC)

Phillip Boles, FireEye, Inc.

Prasad Gaikwad, FireEye, Inc.

Rajeev Jha, FireEye, Inc.

Anuj Kumar, FireEye, Inc.

Shyamal Pandya, FireEye, Inc.

Paul Patrick, FireEye, Inc.

Scott Shreve, FireEye, Inc.

Jon Warren, FireEye, Inc.

Remko Weterings, FireEye, Inc.

Gavin Chow, Fortinet Inc.

Steve Fossen, Fortinet Inc.

Kenichi Terashita, Fortinet Inc.

Ryusuke Masuoka, Fujitsu Limited

Daisuke Murabayashi, Fujitsu Limited

Derek Northrope, Fujitsu Limited

Jonathan Algar, GDS

Iain Brown, GDS

Adam Cooper, GDS

Mike McLellan, GDS

Tyrone Nembhard, GDS

Chris O'Brien, GDS

James Penman, GDS

Howard Staple, GDS

Chris Taylor, GDS

Laurie Thomson, GDS

Alastair Treharne, GDS

Julian White, GDS

Bethany Yates, GDS

Robert van Engelen, Genivia

Eric Burger, Georgetown University

Allison Miller, Google Inc.

Mark Risher, Google Inc.

Yoshihide Kawada, Hitachi, Ltd.

Jun Nakanishi, Hitachi, Ltd.

Kazuo Noguchi, Hitachi, Ltd.

Akihito Sawada, Hitachi, Ltd.

Yutaka Takami, Hitachi, Ltd.

Masato Terada, Hitachi, Ltd.

Peter Allor, IBM

Eldan Ben-Haim, IBM

Allen Hadden, IBM

Sandra Hernandez, IBM

Jason Keirstead, IBM

John Morris, IBM

Laura Rusu, IBM

Ron Williams, IBM

Paul Martini, iboss, Inc.

Jerome Athias, Individual

Peter Brown, Individual

Joerg Eschweiler, Individual

Stefan Hagen, Individual

Elysa Jones, Individual

Sanjiv Kalkar, Individual

Terry MacDonald, Individual

Alex Pinto, Individual

Tim Casey, Intel Corporation

Kent Landfield, Intel Corporation

Karin Marr, Johns Hopkins University Applied Physics Laboratory

Julie Modlin, Johns Hopkins University Applied Physics Laboratory

Mark Moss, Johns Hopkins University Applied Physics Laboratory

Mark Munoz, Johns Hopkins University Applied Physics Laboratory

Nathan Reller, Johns Hopkins University Applied Physics Laboratory

Pamela Smith, Johns Hopkins University Applied Physics Laboratory

David Laurance, JPMorgan Chase Bank, N.A.

Russell Culpepper, Kaiser Permanente

Beth Pumo, Kaiser Permanente

Michael Slavick, Kaiser Permanente

Trey Darley, Kingfisher Operations, sprl

Gus Creedon, Logistics Management Institute

Wesley Brown, LookingGlass

Jamison Day, LookingGlass

Kinshuk Pahare, LookingGlass

Allan Thomson, LookingGlass

Ian Truslove, LookingGlass

Chris Wood, LookingGlass

Greg Back, Mitre Corporation

Jonathan Baker, Mitre Corporation

Sean Barnum, Mitre Corporation

Desiree Beck, Mitre Corporation

Michael Chisholm, Mitre Corporation

Nicole Gong, Mitre Corporation

Ivan Kirillov, Mitre Corporation

Michael Kouremetis, Mitre Corporation

Chris Lenk, Mitre Corporation

Richard Piazza, Mitre Corporation

Larry Rodrigues, Mitre Corporation

Jon Salwen, Mitre Corporation

Charles Schmidt, Mitre Corporation

Alex Tweed, Mitre Corporation

Emmanuelle Vargas-Gonzalez, Mitre Corporation

John Wunder, Mitre Corporation

James Cabral, MTG Management Consultants, LLC.

Scott Algeier, National Council of ISACs (NCI)

Denise Anderson, National Council of ISACs (NCI)

Josh Poster, National Council of ISACs (NCI)

Mike Boyle, National Security Agency

Joe Brule, National Security Agency

Jessica Fitzgerald-McKay, National Security Agency

David Kemp, National Security Agency

Shaun McCullough, National Security Agency

John Anderson, NC4

Michael Butt, NC4

Mark Davidson, NC4

Daniel Dye, NC4

Angelo Mendonca, NC4

Michael Pepin, NC4

Natalie Suarez, NC4

Benjamin Yates, NC4

Daichi Hasumi, NEC Corporation

Takahiro Kakumaru, NEC Corporation

Lauri Korts-P_rn, NEC Corporation

John-Mark Gurney, New Context Services, Inc.

Christian Hunt, New Context Services, Inc.

Daniel Riedel, New Context Services, Inc.

Andrew Storms, New Context Services, Inc.

Stephen Banghart, NIST

David Darnell, North American Energy Standards Board

Cory Casanave, Object Management Group

Aharon Chernin, Perch

Dave Eilken, Perch

Sourabh Satish, Phantom

Josh Larkins, PhishMe Inc.

John Tolbert, Queralt Inc.

Ted Julian, Resilient Systems, Inc..

Igor Baikalov, Securonix

Joseph Brand, Semper Fortis Solutions

Duncan Sparrell, sFractal Consulting LLC

Thomas Schreck, Siemens AG

Rob Roel, Southern California Edison

Dave Cridland, Surevine Ltd.

Bret Jordan, Symantec Corp.

Curtis Kostrosky, Symantec Corp.

Juha Haaga, Synopsys

Masood Nasir, TELUS

Greg Reaume, TELUS

Alan Steer, TELUS

Crystal Hayes, The Boeing Company

Wade Baker, ThreatConnect, Inc.

Cole Iliff, ThreatConnect, Inc.

Andrew Pendergast, ThreatConnect, Inc.

Ben Schmoker, ThreatConnect, Inc.

Jason Spies, ThreatConnect, Inc.

Ryan Trost, ThreatQuotient, Inc.

Patrick Coughlin, TruSTAR Technology

Chris Roblee, TruSTAR Technology

Mark Angel, U.S. Bank

Brian Fay, U.S. Bank

Joseph Frazier, U.S. Bank

Mark Heidrick, U.S. Bank

Mona Magathan, U.S. Bank

Yevgen Sautin, U.S. Bank

Richard Shok, U.S. Bank

James Bohling, US Department of Defense (DoD)

Eoghan Casey, US Department of Defense (DoD)

Gary Katz, US Department of Defense (DoD)

Jeffrey Mates, US Department of Defense (DoD)

Evette Maynard-Noel, US Department of Homeland Security

Robert Coderre, VeriSign

Kyle Maxwell, VeriSign

Eric Osterweil, VeriSign

Patrick Maroney, Wapack Labs LLC

Anthony Rutkowski, Yanna Technologies LLC



​Appendix C. Revision History

Revision

Date

Editor

Changes Made

01

2017-01-20

Bret Jordan,

John Wunder,

Rich Piazza,

Ivan Kirillov,

Trey Darley

Initial Version

02

2017-04-24

Bret Jordan,

John Wunder,

Rich Piazza,

Ivan Kirillov,

Trey Darley

Changes made from first public review

stix-v2.0-wd03-part1-stix-core                                       Working Draft 03                                                                       19 June 2017

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