  A Digital Twin (DT) is a digital representation of a physical object used to
simulate it before it is built or to predict failures after the object is
deployed. The DT concept was originally applied to manufacturing but has been
gaining attention in other areas. In this article, we introduce a novel concept
called Cyber Digital Twin (CDT), which transfers the idea of the DT to
automotive software for the purpose of security analysis. In our approach, the
ECU software (i.e., firmware) is transformed into a CDT, which contains
automatically extracted, security-relevant information from the firmware. With
this, we can evaluate automotive security requirements through automated
security requirements verification using policy enforcement checks and
detection of security vulnerabilities. The evaluation can be done continuously
using newly integrated checks and published security vulnerabilities.
