Nested trust boundaries

[harsh02]

Is it possible to put same asset in two boundaries? For example:

I am building a threat model for how devices secrets are saved multiple ways. I have device trust boundary but within that device some assets should be placed in separate boundaries like eHSM which exist in same device but have separate trust level. I want to showcase this in nested trust boundary way.

thanks!

[raphaelahrens]

Hi,

I'm not quite sure if I understand your request correctly, but maybe I can help.

What is currently possible is that you nest boundaries via bounadry_x.inBoundary = boundary_y.

tm = TM("my test tm")

vm = Boundary("Vertiual machine")
server_db = Boundary("Server/DB")
server_db.inBoundary = vm
server_web = Boundary("Server/DB")
server_web.inBoundary = vm
web = Server("Web Server  a")
web.inBoundary = server_web

db = Datastore("SQL Database")
db.inBoundary = server_db

What currently is not possible is to have an element in two boundaries, like this element.inBoundary = [boundray_x, boundary_y]. But this might be a something that could be changed.

[harsh02]

Yes, thats what I am looking for to place element in two boundaries but I guess there might more logic needed to define like inner or outer boundary something like that.

[izar]

@harsh02 would you be able to describe a use case for what you're looking for? I am having difficulty seeing it conceptually.