Please refer to the below image representing the high-level TARA workflow that reflects the ISO 21434 regulation. The
Item Definition is a pre-condition of a TARA, followed by the
Asset Identification that is associated with the
Security Properties which lead to the
Impact Rating. Proceeding with the
Threat Analysis that evaluates the probability of the potential
Attack Steps as well as the likelihood to achieve them.
In addition, you can analyze the conceivable risks related to your
Item Definition on which you can decide whether this would be acceptable, otherwise appropriate countermeasures have to be applied in order to mitigate the identified risk. We call them
Controls. Basically, once you have modelled your TARA end-to-end, you will be able to evaluate the
Impact and the
Attack Feasibility which will result in an overall
Risk Level.