STIX & TAXII - Complete Knowledge

Note: This is a personal knowledge hub that I am trying to create, some of the information can be misleading or wrong, please use this with caution!

Introduction

STIX

What is STIX and What is TAXII? In the most simple terms STIX is a model of Threat Intelligence that is represented in motivations, abilities, capabilities and response objects. Those objects are then represented in either JSON (STIX 2) or XML (STIX 1).

Here is a very simple representation of STIX Objects in a graph.

Explanation of the example

The data can be helpful for preventing or mitigating various kinds of attacks that can be expressed with STIX. All the list of the examples you can find in their official example page.

TAXII

The STIX data has to be relayed in some way, that's why we have the TAXII Server. It is a simple web server specifically created for storing and sharing that kind of data.

TAXII 1.x Structure

The TAXII 1.2 Server has the following structure:

• Discovery Service - Within a POST request to their discovery URL (which should be pointed by the Server maintainers).
• Collection Management URL - The service that has the collections with STIX objects.
• Channels - Push/Subscribe pattern.

The full list of features for TAXII1 can be found in their official documentation:

• https://docs.oasis-open.org/cti/taxii/v1.1.1/taxii-v1.1.1-part3-http.html
• https://taxiiproject.github.io/releases/1.1/TAXII_Overview.pdf
• https://www.oasis-open.org/committees/download.php/57324/OASIS

TAXII 2.x Structure

For the newer versions of the TAXII Server we have the following structure:

• /discovery - Discovers the paths to the different services provided by the Server.
• api_roots - Provides the API URLs for the different types of Collection Management.
  • collections - Provides the available collections for the given api_root.
    • collection/objects - Provides a list of STIX Objects in a given collection

You can see that this is very similar to the TAXII 1.x servers, there isn't much of a difference in the structure besides that the collection_management_url is api_root in TAXII 2.x.

The full list of features for TAXII2 can be found in their official documentation.

TAXII Servers and Threat Intelligence Providers

The information about this is very scarce so I've gathered a quick list of the known providers for STIX data.

Tools for STIX/TAXII

The main tool for creating/parsing or generating STIX data is going to be Python, since that all of the tools created are written in Python. Of course there are other alternatives but currently that's the most common one.

Other tools that might come in handy.

Snippets and Gists

• https://gist.github.com/syrull/6a2614560fb0474df166a51bcb34990d (Creating a TAXII2 Client for LimoAnomali)
• https://gist.github.com/syrull/73b1798f90c4109a13ef9fceb1f2f858 (Creating a TAXII1 Client for OTXAlienVault)