Catalyzing security in service orientation

Blogger: Ramon Krikken

Many different conference tracks, many different perspectives on 'security' and how to best implement it. I spent most of my time in the Service-Oriented Architecture (SOA) track, looking for little nuggets of wisdom to help with my upcoming SOA security overview, and I certainly did find some. There were - luckily - no huge upsets, but there were certainly lots of questions on how to to implement controls in a service-oriented environment. What was once only the question of what Web Services standards to use, has now evolved to discussions on everything from high-level architecture to the minutiae of security token translations.

One of the discussions in SOA security revolves around the location of controls. In general the architecture is best served if most controls, such as authentication and authorization, are externalized from the application code. It creates a separation of concerns, and usually makes management and auditing more straightforward. So some of the different infrastructure components, like web services modules and the XML gateways, support access control, encryption, and data validation features. Some vendors would like us to believe that pushing all this functionality into their well-packaged, standards-based solution is going to solve the 'security problem,' but does it?

It all works out well as long as we can - in the true spirit of service orientation - view the service as a black box, but that isn't necessarily possible from a security perspective. Certain functionality, like the compute-intensive XML schema validation, is an ideal candidate for infrastructure security, and so is service-to-service authentication. User authorization is all over the map depending on its granularity and requirements for data-awareness. With encryption it also depends on whether we're talking data transport or storage. Service-enabling legacy applications also throws us a curve-ball because of, amongst things, the need for identity and access token mapping that take us into the darkness of the black-box service.

In other words, both applying controls in service orientation, and applying service-oriented principles to security, aren't necessarily as straightforward as some may want us to believe. Security professionals probably already had a feeling this would be the case; we're a bunch of skeptics, after all. But if it's the case that enterprise architecture is far ahead of security architecture in SOA planning or implementation, then there may be some misunderstanding in the organization on how to secure the infrastructure and services. At the surface, and in the common case, the decision to put controls at the infrastructure level seems simple. The devil, it appears, is very much in the details that are invisible to us in some of the higher-level architectural discussions.

Fortunately, all is not lost. We may have thought that 'the SOA train has left the station, and security is not on board,' but it now appears - at least from Burton Group's research - that the train isn't necessarily all too far down the tracks yet. We need to work with the architects to create a security strategy that matures along with the other aspects of SOA implementation, work with the development team to overcome the challenges of building security into the SDLC, and most of all, work with ourselves to make sure we're able to apply consistent principles of information assurance no matter what the next best thing in SOA technology is. There is time to get things right, and the best time to start is now.