Tools / Microsoft Threat Modeling Tool (TMT) Interview questions
What is a data flow in a threat model diagram?
A data flow is the arrow connecting two elements on a TMT diagram, representing data moving from one to the other, such as a browser sending a login request to a web server.
Direction matters: a flow can be one-way or marked bidirectional, and TMT treats the two differently at generation time. A flow that isn't connected to a real source and destination doesn't generate meaningful threats, since the rules key off what the flow connects and whether it crosses a trust boundary.
In practice, data flows are where a large share of the interesting threats live, particularly Tampering and Information Disclosure, because that's the point where an attacker positioned on the network can intercept or alter data in transit.
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