  Cooperative Intelligent Transportation Systems (cITS) are a promising
technology to enhance driving safety and efficiency. Vehicles communicate
wirelessly with other vehicles and infrastructure, thereby creating a highly
dynamic and heterogeneously managed ad-hoc network. It is these network
properties that make it a challenging task to protect integrity of the data and
guarantee its correctness. A major component is the problem that traditional
security mechanisms like PKI-based asymmetric cryptography only exclude
outsider attackers that do not possess key material. However, because attackers
can be insiders within the network (i.e., possess valid key material), this
approach cannot detect all possible attacks. In this survey, we present
misbehavior detection mechanisms that can detect such insider attacks based on
attacker behavior and information analysis. In contrast to well-known intrusion
detection for classical IT systems, these misbehavior detection mechanisms
analyze information semantics to detect attacks, which aligns better with
highly application-tailored communication protocols foreseen for cITS. In our
survey, we provide an extensive introduction to the cITS ecosystem and discuss
shortcomings of PKI-based security. We derive and discuss a classification for
misbehavior detection mechanisms, provide an in-depth overview of seminal
papers on the topic, and highlight open issues and possible future research
trends.
