# On the Modeling of Automotive Security: A Survey of Methods and Perspectives
## 1 Introduction  
With the rapid development of the high technologies, such as Mobile Internet, Big Data, Artificial Intelligence and Cloud Computing, the automobile has gradually become a new-type of intelligent travel carrier [1; 2]. There are more and more communication demands and scenarios between automobiles and the external. Due to interconnection and intelligence, the automobile is transformed from a closed system to open. Nevertheless, it also provides more connecting controllers and sensors for the attackers to be exploited, especially when the access to Internet is activated. Compromising the security of the automobile results in not only financial loss and a privacy breach, but also malicious control and a threat to safety. A demonstrative attack was conducted to remotely disable the car's brakes on a highway [3]. Recently, researchers and white hat hackers explored and manifested a number of the vulnerabilities of automobiles as shown in [4; 5; 6; 7; 8]. In the beginning, automotive security mainly concerned the locking systems and immobilizers because of the usage of keyless entry systems [9]. Many studies have demonstrated the possibility to access the system without permission [10; 11; 12; 13; 14]. With the increasing connectivity of vehicles, the external communication can be seen as new attack surfaces in modern vehicles. For example, there are various services that could affect cybersecurity, such as communicating via telematics system, connecting to OBD (on-board diagnostics) port, or reflashing ECUs (Electronic Control Unit) by OTA (Over-The-Air). The feasibility to attack vehicles by exploiting the potential weakness in these services are examined in [15]. Additionally, the manipulations from wireless connection are also used to perform attacks [16; 17; 18; 19]. Since the autonomous vehicles on levels 2 and above need to be equipped with dozens of sensors for collecting data from the environment [20], they are vulnerable to a variety of possible security attacks [21; 22]. The cameras on vehicles can be blinded [23] and the LiDAR system can be deceived with fake echoes [24]. Reference [25] listed the automotive security incidents from 2010 to 2019. Reference [26] surveyed the theoretical and practical attacks with different approaches and [27] provided a comprehensive taxonomy so that the information derived from attacks can be used for vehicular development and testing. It is significant to attach great importance to the security of intelligent connected automobiles since the security threats are increasing substantially. Moreover, it is necessary to implement well-grounded security practices for ITS. Managing the security on different levels is a basic requirement for security activity. Therein, the elemental step is to assess and prioritize the risks with security analysis techniques. In order to improve the security of the system, we need firstly to understand what threat and risk the system will confront. The interaction and information that influence the system should be processed and analyzed primarily. It is necessary to utilize systematic approaches to identify the vulnerabilities and the latent threats. Based on that, the security objectives can be settled and the countermeasures to mitigate the risk impacts can be derived. A security model can be built to explore all the correlated factors in an organized manner [28]. Instead of simply brainstorming and informal group discussions of the possible intentions of the adversaries, security models are exploited systematically to investigate the vulnerabilities to ensure high coverage. It is particularly important for cyber-physical systems like automobiles since it has direct physical effects on the environment instead of virtual ones [29]. Security models are developed to describe the security characteristics of systems formally and to explain the reasons for the security-related behaviors of systems accurately [30].