I've blogged several times over the past couple of years on zero trust and CARTA (thinking OAuth2 and Contextual Binding, Implementing Zero Trust in AM 6.0, Set Session Limits Using Context) and the topic came up again this week with a customer. A did a simple demo based on the transactional authorization strategy within the AM PDP along with a simple user-agent comparator Intelligent Access tree, so I thought I'd blog it out.
Capture Context During Login
There are lots of authentication nodes we ship in AM and in the ForgeRock marketplace that capture and analyse context. For simplicity I just capture the user-agent - and for the demo just pop the value into the session properties object. In a real world, you'd probably use something more granular and probably hash the value too for privacy preservation.
The login process occurs are normal, but the resulting session object then contains extra context, which we can re-use in a minute.
Sessions are only really useful, if you use them - typically to access resource or perform a transaction. The AM PDP has an environmental condition called transactional - which needs fulfilling on every request - a bit like a stateless event. In this case, I'll create a simple REST resource object that a single page app will request access to.
The AM authorization policy is trivial and simply requires the user to have a valid session and then pass a transactional condition - and this condition will perform a simple contextual compare.
The transactional condition is based on a tree from Intelligent Access, which is basically just a few lines of script to perform a compare of the session properties user agent and the current user agent.
Processing the event is simply a set of REST calls to the PDP - firstly one to perform an policy evaluate, which responds back with a TX (transaction) Id.
The TXid is then sent to the Intelligent Access tree via a composite advice payload to go through the DeviceCheck tree. Once that is complete (as it's script driven, no interactive callbacks need completing), a final call is made back to the PDP with the associated transaction ID to get the go ahead with a set of actions that are allowed. In this case a basic GET:true.
If a difference occurs (which is simple to demo with a user-agent chooser plugin) the event is stopped - but more likely especially in a CARTA world, an advice payload could explain why and perhaps allow a restricted or reduced set of actions to take place.