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The filter call is attempting to use the "stix_objects" iterable but it has not been defined
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Introduction

This document describes how to query and manipulate ATT&CK data from either this repository or the ATT&CK TAXII server, as well as the formatting of the data itself.

The programmatic uses of ATT&CK demonstrated in this document utilize the stix2 python library. Please refer to the STIX2 Python API Documentation for more information on how to work with STIX programmatically. See also the section on Requirements and imports.

This document describes how ATT&CK implements and extends the STIX format. To find out more about STIX, please see the STIX 2.0 website.

We also recommend reading the ATT&CK Design and Philosophy Paper, which describes high-level overall approach, intention, and usage of ATT&CK.

Table of Contents

The ATT&CK data model

The data in this repository is STIX 2.0 and divided into folders, one for each domain of ATT&CK. These domains generally follow the same format with a few departures. Domain differences will be noted in the relevant sections of this document.

ATT&CK uses a mix of predefined and custom STIX objects to implement ATT&CK concepts. The following table is a mapping of ATT&CK concepts to STIX 2.0 objects:

ATT&CK concept STIX object type Custom type?
Matrix x-mitre-matrix yes
Tactic x-mitre-tactic yes
Technique attack-pattern no
Sub-technique attack-pattern where x_mitre_is_subtechnique = true no
Procedure relationship where relationship_type = "uses" and target_ref is an attack-pattern no
Mitigation course-of-action no
Group intrusion-set no
Software malware or tool no

Two additional object types are found in the ATT&CK catalog:

STIX object type About
identity Referenced in the created_by_ref of all objects to state that the MITRE Corporation created the object
marking-definition Referenced in the object_marking_refs of all objects to express the MITRE Corporation copyright

Extensions of the STIX spec

There are three general ways that ATT&CK extends the STIX 2.0 format:

  • Custom object types. Object types prefixed with x-mitre-, e.g x-mitre-matrix, are custom STIX types extending the STIX 2.0 spec. They follow the general STIX Domain Object pattern but describe concepts not covered by types defined in STIX 2.0.

  • Extensions of existing object types. Fields extending the STIX 2.0 spec are prefixed with x_mitre_, e.g x_mitre_platforms in attack-patterns.

    All objects except relationships can have the following extended properties applied:

    Field Type Description
    x_mitre_version string The version of the object in format major.minor where major and minor are integers. ATT&CK increments this version number when the object content is updated.
    x_mitre_contributors string[] People and organizations who have contributed to the object.
    x_mitre_deprecated boolean See Working with deprecated and revoked objects.
  • New relationship types. Unlike custom object types and extended fields, custom relationship types are not prefixed with x_mitre_. You can find a full list of relationship types in the Relationships section, which also mentions whether the type is a default STIX type.

Please see also the STIX documentation on customizing STIX.

IDs in ATT&CK

Objects in ATT&CK may have several different kinds of IDs.

ATT&CK IDs

The most commonly used ID format is what is referred to as the ATT&CK ID or simply ID. Each different type of ATT&CK object has its own variation upon the ATT&CK ID format:

ATT&CK concept ID format
Matrix MAxxxx
Tactic TAxxxx
Technique Txxxx
Sub-Technique Txxxx.yyy
Mitigation Mxxxx
Group Gxxxx
Software Sxxxx

ATT&CK IDs are typically, but not always, unique. See Collisions with Technique ATT&CK IDs for an edge case involving ID collisions between mitigations and techniques.

ATT&CK IDs can be found in the first external reference of all objects except for relationships (which don't have ATT&CK IDs). The first external reference also includes a url field linking to the page describing that object on the ATT&CK Website.

STIX IDs

In addition to ATT&CK IDs, all objects in ATT&CK (including relationships) have STIX IDs in the id field of the object. Unlike ATT&CK IDs, STIX IDs are guaranteed to be unique. STIX IDs are therefore the best way to retrieve and refer to objects programmatically.

Other IDs

Several other IDs can be found in the external references of an object:

  1. NIST Mobile Threat Catalogue IDs can be found for some techniques in the Mobile domain where the external reference source_name is "NIST Mobile Threat Catalogue"
  2. CAPEC IDs can be found for some techniques in the Enterprise domain where the external reference source_name is "capec"

ATT&CK Types

Matrices

The overall layout of the ATT&CK Matrices is stored in x-mitre-matrix objects. As a custom STIX type they follow only the generic STIX Domain Object pattern.

Matrices extend the generic SDO format with the following field:

Field Type Description
tactic_refs string[] The tactic_refs array of the matrix contains an ordered list of x-mitre-tactic STIX IDs corresponding to the tactics of the matrix. The order of tactic_refs determines the order the tactics should appear within the matrix.

Mapping matrices, tactics and techniques

Techniques map into tactics by use of their kill_chain_phases property. Where the kill_chain_name is mitre-attack, mitre-mobile-attack, or mitre-ics-attack (for enterprise, mobile, and ics domains respectively), the phase_name corresponds to the x_mitre_shortname property of an x-mitre-tactic object. Matrices define their tactics in order using the tactic_refs embedded relationships.

matrix, tactic and technique data model

Tactics

A Tactic in ATT&CK is defined by an x-mitre-tactic object. As a custom STIX type they follow only the generic STIX Domain Object pattern.

Tactics extend the generic SDO format with the following field:

Field Type Description
x_mitre_shortname string The x_mitre_shortname of the tactic is used for mapping techniques into the tactic. It corresponds to kill_chain_phases.phase_name of the techniques in the tactic. See mapping matrices, tactics and techniques for more information.

Techniques

A Technique in ATT&CK is defined as an attack-pattern object.

Techniques depart from the attack-pattern format with the following fields. Domain and tactic specific fields are marked in the "applies to" column:

Field Type Applies to Description
x_mitre_detection string All techniques Strategies for identifying if a technique has been used by an adversary.
x_mitre_platforms string[] All techniques List of platforms that apply to the technique.
x_mitre_data_sources string[] Enterprise and ICS domains Sources of information that may be used to identify the action or result of the action being performed.
x_mitre_is_subtechnique boolean Enterprise domain If true, this attack-pattern is a sub-technique. See sub-techniques.
x_mitre_system_requirements string Enterprise domain Additional information on requirements the adversary needs to meet or about the state of the system (software, patch level, etc.) that may be required for the technique to work.
x_mitre_tactic_type string[] Mobile domain "Post-Adversary Device Access", "Pre-Adversary Device Access", or "Without Adversary Device Access".
x_mitre_permissions_required string[] Enterprise domain in the Privilege Escalation tactic The lowest level of permissions the adversary is required to be operating within to perform the technique on a system.
x_mitre_effective_permissions string[] Enterprise domain in the Privilege Escalation tactic The level of permissions the adversary will attain by performing the technique.
x_mitre_defense_bypassed string[] Enterprise domain in the Defense Evasion tactic List of defensive tools, methodologies, or processes the technique can bypass.
x_mitre_remote_support boolean Enterprise domain in the Execution tactic If true, the technique can be used to execute something on a remote system.
x_mitre_impact_type string[] Enterprise domain in the Impact tactic Denotes if the technique can be used for integrity or availability attacks.

See mapping matrices, tactics and techniques for more information about how techniques map into tactics and matrices.

Sub-Techniques

A sub-technique in ATT&CK is represented as an attack-pattern and follows the same format as techniques. They differ in that they have a boolean field (x_mitre_is_subtechnique) marking them as sub-techniques, and a relationship of the type subtechnique-of where the source_ref is the sub-technique and the target_ref is the parent technique. A sub-technique can only have 1 parent technique, but techniques can have multiple sub-techniques.

Additionally:

  • Sub-technique ATT&CK IDs are a suffix of their parent IDs. For a given sub-technique ID Txxxx.yyy, Txxxx is the parent technique ID and yyy is the sub-technique ID. Sub-techniques have unique STIX IDs.
  • Sub-techniques have the same tactics as their parent technique.
  • Sub-techniques have a subset of their parent technique's platforms.

Sub-techniques only exist in the enterprise domain.

Procedures

ATT&CK does not represent procedures under their own STIX type. Instead, procedures are represented as relationships of type uses where the target_ref is a technique. This means that procedures can stem from usage by both groups (intrusion-sets) and software (malware or tools). The content of the procedure is described in the relationship description.

Mitigations

A Mitigation in ATT&CK is defined as a course-of-action object. ATT&CK Mitigations do not depart from the STIX course-of-action spec.

Collisions with technique ATT&CK IDs

In ATT&CK versions prior to v5 (released in July of 2019), mitigations had 1:1 relationships with techniques and shared their technique's ID. These old 1:1 mitigations are deprecated in subsequent ATT&CK releases, and can be filtered out in queries — see Removing revoked and deprecated objects.

Groups

A Group in ATT&CK is defined as an intrusion-set object. ATT&CK Groups do not depart from the STIX intrusion-set format.

Software

Software in ATT&CK is the union of two distinct STIX types: malware and tool.

Both malware and tool type software depart from the STIX format with the following fields:

Field Type Description
x_mitre_platforms string[] List of platforms that apply to the software.
x_mitre_aliases string[] List of aliases for the given software

Relationships

Objects in ATT&CK are related to each other via STIX relationship objects. These relationships convey concepts like groups using techniques (also called "procedure examples" on the technique pages), the hierarchy of techniques and sub-techniques, and so on.

relationships data model

Unlike other objects in the dataset, relationships cannot be revoked or deprecated. Relationships are considered deprecated/revoked if one of the objects it is attached to is revoked or deprecated. See Working with deprecated and revoked objects for more information on revoked objects.

Relationships oftentimes have descriptions which contextualize the relationship between the objects.

Source Type Relationship Type Target Type Custom Type? About
intrusion-set uses malware or tool No Group using a software.
intrusion-set uses attack-pattern No Group using a technique, which is also considered a procedure example.
malware or tool uses attack-pattern No Software using a technique, which is also considered a procedure example.
course-of-action mitigates attack-pattern No Mitigation mitigating technique.
attack-pattern subtechnique-of attack-pattern Yes Sub-technique of a technique, where the source_ref is the sub-technique and the target_ref is the parent technique.
any type revoked-by any type Yes The target object is a replacement for the source object. Only occurs where the objects are of the same type, and the source object will have the property revoked = true. See Working with deprecated and revoked objects for more information on revoked objects.

Note that because groups use software and software uses techniques, groups can be considered indirect users of techniques used by their software. See Getting techniques used by a group's software.

Accessing ATT&CK data in python

There are several ways to acquire the ATT&CK data in Python. All of them will provide an object implementing the DataStore API and can be used interchangeably with the recipes provided in the Python recipes section.

This section utilizes the stix2 python library. Please refer to the STIX2 Python API Documentation for more information on how to work with STIX programmatically.

Requirements and imports

Before installing requirements, we recommend setting up a virtual environment:

  1. Create virtual environment:
    • macOS and Linux: python3 -m venv env
    • Windows: py -m venv env
  2. Activate the virtual environment:
    • macOS and Linux: source env/bin/activate
    • Windows: env/Scripts/activate.bat

stix2

stix2 can be installed by following the instructions on their repository. Imports for the recipes in this repository can be done from the base package, for example:

from stix2 import Filter

However, if you are aiming to extend the ATT&CK dataset with new objects or implement complex workflows, you may need to use the v20 specifier for some imports. This ensures that the objects use the STIX 2.0 API instead of the STIX 2.1 API. For example:

from stix2.v20 import AttackPattern

You can see a full list of the classes which have versioned imports here.

taxii2client

taxii2-client can be installed by following the instructions on their repository. The ATT&CK TAXII server implements the 2.0 version of the TAXII specification, but the default import of taxii2client (version 2.0.0 and above) uses the 2.1 version of the TAXII specification, which can lead to 406 responses when connecting to our TAXII server if not accounted for.

If the TAXII Client is getting a 406 Response, make sure you are running the latest version (pip install --upgrade stix2 or pip install --upgrade taxii2-client). In addition, make sure you are running the 2.0 version of the client (using the v20 import) as shown below in order to communicate with the ATT&CK TAXII 2.0 Server.

from taxii2client.v20 import Collection

Access local content

Many users may opt to access the ATT&CK content via a local copy of the STIX data on this repo. This can be advantageous for several reasons:

  • Doesn't require internet access after the initial download
  • User can modify the ATT&CK content if desired
  • Downloaded copy is static, so updates to the ATT&CK catalog won't cause bugs in automated workflows. User can still manually update by cloning a fresh version of the data

Access via FileSystemSource

Each domain in this repo is formatted according to the STIX2 FileSystem spec. Therefore you can use a FileSystemSource to load a domain, for example to load the enterprise-attack domain:

from stix2 import FileSystemSource

src = FileSystemSource('./cti/enterprise-attack')

Access via bundle

If you instead prefer to download just the domain bundle, e.g enterprise-attack.json, you can still load this using a MemoryStore:

from stix2 import MemoryStore

src = MemoryStore()
src.load_from_file("enterprise-attack.json")

Access live content

Some users may instead prefer to access "live" ATT&CK content over the internet. This is advantageous for several reasons:

  • Always stays up to date with the evolving ATT&CK catalog
  • Doesn't require an initial download of the ATT&CK content, generally requires less setup

Access from the ATT&CK TAXII server

Users can access the ATT&CK data from the official ATT&CK TAXII server. In TAXII, the ATT&CK domains are represented as collections with static IDs:

domain collection ID
enterprise-attack 95ecc380-afe9-11e4-9b6c-751b66dd541e
mobile-attack 2f669986-b40b-4423-b720-4396ca6a462b
ics-attack 02c3ef24-9cd4-48f3-a99f-b74ce24f1d34

You can also get a list of available collection from the server directly:

from taxii2client.v20 import Server # only specify v20 if your installed version is >= 2.0.0

server = Server("https://cti-taxii.mitre.org/taxii/")
api_root = server.api_roots[0]
# Print name and ID of all ATT&CK domains available as collections
for collection in api_root.collections:
    print(collection.title.ljust(20) + collection.id)

The following recipe demonstrates how to access the enterprise-attack data from the TAXII server.

from stix2 import TAXIICollectionSource
from taxii2client.v20 import Collection # only specify v20 if your installed version is >= 2.0.0

collections = {
    "enterprise_attack": "95ecc380-afe9-11e4-9b6c-751b66dd541e",
    "mobile_attack": "2f669986-b40b-4423-b720-4396ca6a462b",
    "ics-attack": "02c3ef24-9cd4-48f3-a99f-b74ce24f1d34"
}

collection = Collection(f"https://cti-taxii.mitre.org/stix/collections/{collections['enterprise_attack']}/")
src = TAXIICollectionSource(collection)

For more about TAXII, please see oasis-open's Introduction to TAXII.

Access from Github via requests

Users can alternatively access the data from MITRE/CTI using HTTP requests, and load the resulting content into a MemoryStore. While typically the TAXII method is more desirable for "live" access, this method can be useful if you want to access data on a branch of the MITRE/CTI repo (the TAXII server only holds the master branch) or in the case of a TAXII server outage.

import requests
from stix2 import MemoryStore

def get_data_from_branch(domain, branch="master"):
    """get the ATT&CK STIX data from MITRE/CTI. Domain should be 'enterprise-attack', 'mobile-attack' or 'ics-attack'. Branch should typically be master."""
    stix_json = requests.get(f"https://raw.githubusercontent.com/mitre/cti/{branch}/{domain}/{domain}.json").json()
    return MemoryStore(stix_data=stix_json["objects"])

src = get_data_from_branch("enterprise-attack")

Access a specific version of ATT&CK

ATT&CK versions are tracked on the MITRE/CTI repo using tags. Tags prefixed with ATT&CK-v correspond to ATT&CK versions and tags prefixed with CAPEC-v correspond to CAPEC versions. You can find more information about ATT&CK versions on the versions of ATT&CK page on the ATT&CK website.

In addition to checking out the repo under the tag for a given version or downloading the STIX from github using your browser, you can also use a variation on the requests method to access a particular version of ATT&CK:

import requests
from stix2 import MemoryStore

def get_data_from_version(domain, version):
    """get the ATT&CK STIX data for the given version from MITRE/CTI. Domain should be 'enterprise-attack', 'mobile-attack' or 'ics-attack'."""
    stix_json = requests.get(f"https://raw.githubusercontent.com/mitre/cti/ATT%26CK-v{version}/{domain}/{domain}.json").json()
    return MemoryStore(stix_data=stix_json["objects"])

src = get_data_from_version("enterprise-attack", "5.2")

You can get a list of ATT&CK versions programmatically using the github API:

import requests
import re

refToTag = re.compile(r"ATT&CK-v(.*)")
tags = requests.get("https://api.github.com/repos/mitre/cti/git/refs/tags").json()
versions = list(map(lambda tag: refToTag.search(tag["ref"]).groups()[0] , filter(lambda tag: "ATT&CK-v" in tag["ref"], tags)))
# versions = ["1.0", "2.0", ...]

Access multiple domains simultaneously

Because ATT&CK is stored in multiple domains (as of this writing, enterprise-attack, mobile-attack and ics-attack), the above methodologies will only allow you to work with a single domain at a time. While oftentimes the hard separation of domains is advantageous, occasionally it is useful to combine domains into a single DataStore. Use any of the methods above to acquire the individual datastores, and then use the following approach to combine them into a single CompositeDataSource:

from stix2 import CompositeDataSource

src = CompositeDataSource()
src.add_data_sources([enterprise_attack_src, mobile_attack_src, ics_attack_src])

You can then use this CompositeDataSource just as you would the DataSource for an individual domain.

Python recipes

Below are example python recipes which can be used to work with ATT&CK data. They assume the existence of an object implementing the DataStore API. Any of the methods outlined in the Accessing ATT&CK data in python section should provide an object implementing this API.

This section utilizes the stix2 python library. Please refer to the STIX2 Python API Documentation for more information on how to work with STIX programmatically. See also the section on Requirements and imports.

Getting an object

The recipes in this section address how to query the dataset for a single object.

By STIX ID

The following recipe can be used to retrieve an object according to its STIX ID. This is typically the preferred way to retrieve objects when working with ATT&CK data because STIX IDs are guaranteed to be unique.

g0075 = src.get("intrusion-set--f40eb8ce-2a74-4e56-89a1-227021410142")

By ATT&CK ID

The following recipe can be used to retrieve an object according to its ATT&CK ID:

from stix2 import Filter

g0075 = src.query([ Filter("external_references.external_id", "=", "G0075") ])[0]

Note: in prior versions of ATT&CK, mitigations had 1:1 relationships with techniques and shared their technique's ID. Therefore the above method does not work properly for techniques because technique ATTT&CK IDs are not truly unique. By specifying the STIX type you're looking for as attack-pattern you can avoid this issue.

from stix2 import Filter

t1134 = src.query([ 
    Filter("external_references.external_id", "=", "T1134"), 
    Filter("type", "=", "attack-pattern")
])[0]

The old 1:1 mitigations causing this issue are deprecated, so you can also filter them out that way — see Removing revoked and deprecated objects.

By name

The following recipe retrieves an object according to its name:

from stix2 import Filter

def get_technique_by_name(thesrc, name):
    filt = [
        Filter('type', '=', 'attack-pattern'),
        Filter('name', '=', name)
    ]
    return thesrc.query(filt)
# get the technique titled "System Information Discovery"
get_technique_by_name(src, 'System Information Discovery')

By alias

The following methodology can be used to find the group corresponding to a given alias:

from stix2 import Filter

def get_group_by_alias(thesrc, alias):
    return thesrc.query([
        Filter('type', '=', 'intrusion-set'),
        Filter('aliases', '=', alias)
    ])[0]
    
get_group_by_alias(src, 'Cozy Bear')

Getting multiple objects

The recipes in this section address how to query the dataset for multiple objects.

When working with queries to return objects based on a set of characteristics, it is likely that you'll end up with a few objects which are no longer maintained by ATT&CK. These are objects marked as deprecated or revoked. We keep these outdated objects around so that workflows depending on them don't break, but we recommend you avoid using them when possible. Please see the section Working with deprecated and revoked objects for more information.

Objects by type

See The ATT&CK data model for mappings of ATT&CK type to STIX type.

from stix2 import Filter

# use the appropriate STIX type in the query according to the desired ATT&CK type
groups = src.query([ Filter("type", "=", "intrusion-set") ])

Getting techniques or sub-techniques

ATT&CK Techniques and sub-techniques are both represented as attack-pattern objects. Therefore further parsing is necessary to get specifically techniques or sub-techniques.

from stix2 import Filter

def get_techniques_or_subtechniques(thesrc, include="both"):
    """Filter Techniques or Sub-Techniques from ATT&CK Enterprise Domain.
    include argument has three options: "techniques", "subtechniques", or "both"
    depending on the intended behavior."""
    if include == "techniques":
        query_results = thesrc.query([
            Filter('type', '=', 'attack-pattern'),
            Filter('x_mitre_is_subtechnique', '=', False)
        ])
    elif include == "subtechniques":
        query_results = thesrc.query([
            Filter('type', '=', 'attack-pattern'),
            Filter('x_mitre_is_subtechnique', '=', True)
        ])
    elif include == "both":
        query_results = thesrc.query([
            Filter('type', '=', 'attack-pattern')
        ])
    else:
        raise RuntimeError("Unknown option %s!" % include)

    return query_results


subtechniques = get_techniques_or_subtechniques(src, "subtechniques")
subtechniques = remove_revoked_deprecated(subtechniques) # see https://github.com/mitre/cti/blob/master/USAGE.md#removing-revoked-and-deprecated-objects

Getting software

Because software are the union of two STIX types (tool and malware), the process for accessing software is slightly more complicated.

from itertools import chain
from stix2 import Filter

def get_software(thesrc):
    return list(chain.from_iterable(
        thesrc.query(f) for f in [
            Filter("type", "=", "tool"), 
            Filter("type", "=", "malware")
        ]
    ))

get_software(src)

Objects by content

Sometimes it may be useful to query objects by the content of their description:

from stix2 import Filter

def get_techniques_by_content(thesrc, content):
    techniques = src.query([ Filter('type', '=', 'attack-pattern') ])
    return list(filter(lambda t: content.lower() in t.description.lower(), techniques))

# Get all techniques where the string LSASS appears in the description
get_techniques_by_content(src, 'LSASS')

Techniques by platform

Techniques are associated with one or more platforms. You can query the techniques under a specific platform with the following code:

from stix2 import Filter

def get_techniques_by_platform(thesrc, platform):
    return thesrc.query([
        Filter('type', '=', 'attack-pattern'),
        Filter('x_mitre_platforms', '=', platform)
    ])

# get techniques in the windows platform
get_techniques_by_platform(src, 'Windows')

Techniques by tactic

Techniques are related to tactics by their kill_chain_phases property. The phase_name of each kill chain phase corresponds to the x_mitre_shortname of a tactic.

from stix2 import Filter

def get_tactic_techniques(thesrc, tactic):
    # double checking the kill chain is MITRE ATT&CK
    # note: kill_chain_name is different for other domains:
    #    - enterprise: "mitre-attack"
    #    - mobile: "mitre-mobile-attack"
    #    - ics: "mitre-ics-attack"
    return thesrc.query([
        Filter('type', '=', 'attack-pattern'),
        Filter('kill_chain_phases.phase_name', '=', tactic),
        Filter('kill_chain_phases.kill_chain_name', '=', 'mitre-attack'),
    ])


# use the x_mitre_shortname as argument
get_tactic_techniques(src, 'defense-evasion')

Tactics by matrix

The tactics are individual objects (x-mitre-tactic), and their order in a matrix (x-mitre-matrix) is found within the tactic_refs property in a matrix. The order of the tactics in that list matches the ordering of the tactics in that matrix. The following recipe returns a structured list of tactics within each matrix of the input DataStore.

from stix2 import Filter

def getTacticsByMatrix(thesrc):
    tactics = {}
    matrix = thesrc.query([
        Filter('type', '=', 'x-mitre-matrix'),
    ])
    
    for i in range(len(matrix)):
        tactics[matrix[i]['name']] = []
        for tactic_id in matrix[i]['tactic_refs']:
            tactics[matrix[i]['name']].append(thesrc.get(tactic_id))
    
    return tactics

# get tactic layout
getTacticsByMatrix(src)

Objects created or modified since a given date

Sometimes you may want to get a list of objects which have been created or modified after a certain time.

from stix2 import Filter

def get_created_after(thesrc, timestamp):
    filt = [
        Filter('created', '>', timestamp)
    ]
    return thesrc.query(filt)

get_created_after(src, "2018-10-01T00:14:20.652Z")


def get_modified_after(thesrc, timestamp):
    filt = [
        Filter('modified', '>', timestamp)
    ]
    return thesrc.query(filt)
    
get_modified_after(src, "2018-10-01T00:14:20.652Z")

We don't recommend you use this method to detect a change to the contents of the knowledge base. For detecting an update to the overall knowledge base we recommend using requests to check the list of released versions of ATT&CK.

Getting related objects

A large part of working with ATT&CK revolves around parsing relationships between objects. It is useful to track not only the related object but the relationship itself because a description is often present to contextualize the nature of the relationship. The following recipes demonstrate some common uses of relationships.

Relationships microlibrary

The following microlibrary can be used to build a lookup table of stixID to related objects and relationships. The argument to each accessor function is a STIX2 MemoryStore to build the relationship mappings from.

from stix2 import MemoryStore, Filter
from itertools import chain

def get_related(thesrc, src_type, rel_type, target_type, reverse=False):
    """build relationship mappings
       params:
         thesrc: MemoryStore to build relationship lookups for
         src_type: source type for the relationships, e.g "attack-pattern"
         rel_type: relationship type for the relationships, e.g "uses"
         target_type: target type for the relationship, e.g "intrusion-set"
         reverse: build reverse mapping of target to source
    """

    relationships = thesrc.query([
        Filter('type', '=', 'relationship'),
        Filter('relationship_type', '=', rel_type)
    ])

    # stix_id => [ { relationship, related_object_id } for each related object ]
    id_to_related = {} 

    # build the dict
    for relationship in relationships:
        if (src_type in relationship.source_ref and target_type in relationship.target_ref):
            if (relationship.source_ref in id_to_related and not reverse) or (relationship.target_ref in id_to_related and reverse):
                # append to existing entry
                if not reverse: 
                    id_to_related[relationship.source_ref].append({
                        "relationship": relationship,
                        "id": relationship.target_ref
                    })
                else: 
                    id_to_related[relationship.target_ref].append({
                        "relationship": relationship, 
                        "id": relationship.source_ref
                    })
            else: 
                # create a new entry
                if not reverse: 
                    id_to_related[relationship.source_ref] = [{
                        "relationship": relationship, 
                        "id": relationship.target_ref
                    }]
                else:
                    id_to_related[relationship.target_ref] = [{
                        "relationship": relationship, 
                        "id": relationship.source_ref
                    }]
    # all objects of relevant type
    if not reverse:
        targets = thesrc.query([
            Filter('type', '=', target_type),
        ])
    else:
        targets = thesrc.query([
            Filter('type', '=', src_type),
        ])
    
    # remove revoked and deprecated objects from output
    targets = list(
        filter(
            lambda x: x.get("x_mitre_deprecated", False) is False and x.get("revoked", False) is False,
            targets
        )
    )

    # build lookup of stixID to stix object
    id_to_target = {}
    for target in targets:
        id_to_target[target.id] = target

    # build final output mappings
    output = {}
    for stix_id in id_to_related:
        value = []
        for related in id_to_related[stix_id]:
            if not related["id"] in id_to_target:
                continue # targeting a revoked object
            value.append({
                "object": id_to_target[related["id"]],
                "relationship": related["relationship"]
            })
        output[stix_id] = value
    return output


# software:group
def software_used_by_groups(thesrc):
    """returns group_id => {software, relationship} for each software used by the group."""
    x = get_related(thesrc, "intrusion-set", "uses", "tool")
    x.update(get_related(thesrc, "intrusion-set", "uses", "malware"))
    return x

def groups_using_software(thesrc):
    """returns software_id => {group, relationship} for each group using the software."""
    x = get_related(thesrc, "intrusion-set", "uses", "tool", reverse=True)
    x.update(get_related(thesrc, "intrusion-set", "uses", "malware", reverse=True))
    return x

# technique:group
def techniques_used_by_groups(thesrc):
    """returns group_id => {technique, relationship} for each technique used by the group."""
    return get_related(thesrc, "intrusion-set", "uses", "attack-pattern")

def groups_using_technique(thesrc):
    """returns technique_id => {group, relationship} for each group using the technique."""
    return get_related(thesrc, "intrusion-set", "uses", "attack-pattern", reverse=True)

# technique:software
def techniques_used_by_software(thesrc):
    """return software_id => {technique, relationship} for each technique used by the software."""
    x = get_related(thesrc, "malware", "uses", "attack-pattern")
    x.update(get_related(thesrc, "tool", "uses", "attack-pattern"))
    return x

def software_using_technique(thesrc):
    """return technique_id  => {software, relationship} for each software using the technique."""
    x = get_related(thesrc, "malware", "uses", "attack-pattern", reverse=True)
    x.update(get_related(thesrc, "tool", "uses", "attack-pattern", reverse=True))
    return x

# technique:mitigation
def mitigation_mitigates_techniques(thesrc):
    """return mitigation_id => {technique, relationship} for each technique mitigated by the mitigation."""
    return get_related(thesrc, "course-of-action", "mitigates", "attack-pattern", reverse=False)

def technique_mitigated_by_mitigations(thesrc):
    """return technique_id => {mitigation, relationship} for each mitigation of the technique."""
    return get_related(thesrc, "course-of-action", "mitigates", "attack-pattern", reverse=True)

# technique:subtechnique
def subtechniques_of(thesrc):
    """return technique_id => {subtechnique, relationship} for each subtechnique of the technique."""
    return get_related(thesrc, "attack-pattern", "subtechnique-of", "attack-pattern", reverse=True)

def parent_technique_of(thesrc):
    """return subtechnique_id => {technique, relationship} describing the parent technique of the subtechnique"""
    return get_related(thesrc, "attack-pattern", "subtechnique-of", "attack-pattern")[0]

Example usage:

group_id_to_software = groups_using_software(src)
group_id_to_software["intrusion-set--2a158b0a-7ef8-43cb-9985-bf34d1e12050"] # G0019
# [
#     {
#         "object": Malware, # S0061
#         "relationship": Relationship # relationship between G0019 and S0061
#     },
#     { 
#         ...
#     }
# ]

Getting techniques used by a group's software

Because a group uses software, and software uses techniques, groups can be considered indirect users of techniques used by their software. These techniques are oftentimes distinct from the techniques used directly by a group, although there are occasionally intersections in these two sets of techniques.

The following recipe can be used to retrieve the techniques used by a group's software:

from stix2.utils import get_type_from_id
from stix2 import Filter

def get_techniques_by_group_software(thesrc, group_stix_id):
    # get the malware, tools that the group uses
    group_uses = [
        r for r in thesrc.relationships(group_stix_id, 'uses', source_only=True)
        if get_type_from_id(r.target_ref) in ['malware', 'tool']
    ]

    # get the technique stix ids that the malware, tools use
    software_uses = thesrc.query([
        Filter('type', '=', 'relationship'),
        Filter('relationship_type', '=', 'uses'),
        Filter('source_ref', 'in', [r.source_ref for r in group_uses])
    ])

    #get the techniques themselves
    return thesrc.query([
        Filter('type', '=', 'attack-pattern'),
        Filter('id', 'in', [r.target_ref for r in software_uses])
    ])

get_techniques_by_group_software(src, "intrusion-set--f047ee18-7985-4946-8bfb-4ed754d3a0dd")

Working with deprecated and revoked objects

Objects that are deemed no longer beneficial to track as part of the knowledge base are marked as deprecated, and objects which are replaced by a different object are revoked. In both cases, the old object is marked with a field (either x_mitre_deprecated or revoked) noting their status. In the case of revoked objects, a relationship of type revoked-by is also created targeting the replacing object.

Unlike other objects in the dataset, relationships cannot be revoked or deprecated. Relationships are considered deprecated/revoked if one of the objects it is attached to is revoked or deprecated.

Removing revoked and deprecated objects

Revoked and deprecated objects are kept in the knowledge base so that workflows relying on those objects are not broken. We recommend you filter out revoked and deprecated objects from your views whenever possible since they are no longer maintained by ATT&CK.

We recommend not using built-in STIX filters for removing revoked objects (e.g Filter('revoked', '=', False)). This is because the behavior of this specific filter is inconsistent depending on the method of access (using local data or accessing via the TAXII server). We recommend using the following code example to filter revoked objects instead. See issue #127 for more details.

from stix2 import Filter

def remove_revoked_deprecated(stix_objects):
    """Remove any revoked or deprecated objects from queries made to the data source"""
    # Note we use .get() because the property may not be present in the JSON data. The default is False
    # if the property is not set.
    return list(
        filter(
            lambda x: x.get("x_mitre_deprecated", False) is False and x.get("revoked", False) is False,
            stix_objects
        )
    )

mitigations = src.query([ Filter("type", "=", "course-of-action") ])
mitigations = remove_revoked_deprecated(mitigations)

Getting a revoking object

When an object is replaced by another object, it is marked with the field revoked and a relationship of type revoked-by is created where the source_ref is the revoked object and the target_ref is the revoking object. This relationship can be followed to find the replacing object:

from stix2 import Filter

def getRevokedBy(stix_id, thesrc):
    relations = thesrc.relationships(stix_id, 'revoked-by', source_only=True)
    revoked_by = thesrc.query([
        Filter('id', 'in', [r.target_ref for r in relations]),
        Filter('revoked', '=', False)
    ])
    if revoked_by is not None:
        revoked_by = revoked_by[0]

    return revoked_by

getRevokedBy("attack-pattern--c16e5409-ee53-4d79-afdc-4099dc9292df", src)