STIX and TAXII: On the road to becoming the de facto standard

The road to blissful cyber threat intelligence sharing often feels like a bumpy dirt track in a Wild West ghost town, but there’s hope on the horizon: A new language, designed to define and describe a broad swath of threat activity, is beginning to take shape. This language, known as STIX, and its transport method, called TAXII, offers security firms, industry, and government the promise of better and faster cyber threat intelligence sharing.

STIX and TAXII have been getting key support and backing from groups as diverse as the Department of Homeland Security, The MITRE Corporation, and members of various information security groups and vendors, including Blue Coat Systems. For the past 6 months, I have been heading up Blue Coat’s participation in this effort.

STIX (Structured Threat Information eXpression) is a language used to communicate a set of cyber threat intelligence idioms, including:

·      Threat Actors

·      Campaigns

·      Techniques, Tactics, and Procedures

·      Exploit Targets

·      Indicators

·      Incidents

·      Cyber-Observables

·      Courses of Action

TAXII (Trusted Automated eXchange of Indicator Information) is the preferred delivery mechanism for STIX data. Technically, TAXII is a lightweight XML-over-HTTP transport protocol, specifically designed to deliver STIX data. TAXII allows publishers to share STIX data with (and, optionally, get STIX data from) subscribers, or for peers to share STIX data with other peers.

The STIX and TAXII standards have matured well beyond their initial drafts and first release in 2013. In fact, major vendors are lining up to announce support and governments, incident responders and CERTs, the Financial Services Information Sharing and Analysis Center (FS-ISAC), and the Industrial Control Systems Information Sharing and Analysis Center (ICS-ISAC) (to name a few) have already started using STIX and TAXII in their production environments.

With all new technologies and community driven efforts, there inevitably comes a point when someone asks the question "when will this move to an official international standards body?" It is my opinion that moving right now to an international standards body would just inhibit development and slow down adoption. For the past two years, the amazing grassroots efforts of MITRE and DHS – with the help of FS-ISAC – have produced remarkable results.

In my opinion, four issues are slowing down the adoption of STIX and TAXII as the de facto standard:

Item 1: The absence of a hardened, full-featured, open source, Berkeley Software Distribution (BSD) licensed, TAXII server that end users, enterprises, and vendors can easily use and adapt for their needs. A project currently underway at FS-ISAC called Avalanche may solve this need, in the end. We need the TAXII equivalent of a FreeRADIUS server.  It would be nice if it were highly efficient, fully featured, and written in a compiled language for performance reasons.  

Item 2: Better support for creating and interpreting STIX packages. MITRE has done a lot of good work on creating and maintaining Python APIs, and there are some up and coming Java APIs. However, additional language support is needed; Hopefully, the community will create additional bindings. Part of the issue comes from the debate among contributors about the format that the data will eventually take: XML, JSON, or Cap'n Proto. In my experience, most academics love XML, and most developers ask for anything but XML.

Item 3: A fully featured, standalone GUI client or application – or a combination of the two – that will allow someone to manually create and/or understand STIX packages from their computer and/or mobile device. Even though you can publish STIX data via TAXII, I still see people posting cyber threat information on their Web site, FTP server, or via an RSS feed.  We really need a way of reading those packages and being able to update/change them and re-publish the results back in STIX format. It would be great if this GUI tool could also talk to a remote TAXII server and query it by asking "give me information you have about 'foo' and 'bar'". Having access to a tool like this would make it a lot easier for someone researching issues they see in their own network.   

Item 4: My personal wish item is an analytics tool for the cyber threat data itself.  Once you start collecting large repositories (millions of indicators or bigger) of STIX data.  As repositories of indicators increase in size, it becomes difficult to see the big picture. Imagine having the ability to run some sort of analytics tool on top of your cyber threat intelligence data to make sense of it all: Something that can build correlations while visually helping you research and understand the threat data you have. I could see someone taking a tool like this and overlaying their own traffic to answer interesting questions like 'what types of threat data are actually found in my network?’ and ‘what other entities are seeing the same types of data?' (said another way, 'what threat feeds are the most relevant for my network?').

With every user that jumps on board, every vendor that comes to the table, and—as owners of large cyber threat data decide to play—everyone wins and becomes more secure. As a result, that deserted bumpy road of cyber threat intelligence sharing in the middle of a Wild West ghost town will no longer be deserted, and will become a smooth paved boulevard of information exchange.

Eventually, STIX and TAXII will evolve into the de facto standard because it is the first standard collaboratively created by the people that actually WANT to share and WILL share critical cyber threat intelligence.