Security Evaluation of an Airbag-ECU by Reusing Threat Modeling Artefacts

In this work we present an approach to derive test cases for security testing by reusing threat modeling artefacts. We suggest to perform a threat modeling in an early stage of the product life cycle and show how these threat models, originally created for the security design phase, can be reused for security testing. We further show the practical applicability of our approach by describing the creation, execution and evaluation of a penetration test for an Electronic Control Unit (ECU). For the evaluation of our approach we selected a Pyrotechnic Control Unit (PCU) due to its safety critical functionality, which is commonly referred to as an Airbag-ECU. This scenario leads to a safety impact as a PCU is connected to pyrotechnic charges, e.g., airbags, that can lead to serious injury or death, if deployed in a non-appropriate scenario. During this penetration test, the selected PCU was installed on a test bench. We were able to successfully exploit a found vulnerability, causing the deployment of charges.