# Cybersecurity Challenges in the Maritime Sector
## 1 Introduction  
Today's global maritime sector is increasingly reliant on digitalisation, operational integration, and automation [1, 2]. Leading shipbuilders and operators seek to innovate by utilizing cutting-edge technologies and systems that go beyond traditional designs to create ships with advanced remote control, communication, and connectivity capabilities [3]. Those capabilities are tested through various autonomous vessel projects. Mayflower was the first fully autonomous vessel that attempted to cross the Atlantic Ocean by using Artificial Intelligence (AI) technology and the energy from the Sun [4]. The vessel failed in its first attempt to cross the Atlantic, but it will try to sail across the Atlantic again this year. The Nippon Foundation will also test the first fully autonomous long-range commercial sail by February 2022 [5]. Autonomous vessels and modern ships contain a fleet of sensors (e.g., radar, LiDAR, high-definition cameras, thermal imaging, sonar, etc.) and many Operational Technology (OT) systems, which are interconnected with each other to give the ship's AI a precise combined image of the surrounding environment [6, 7]. Their levels of automation can progress from fully manned ships to partially operated, remotely operated, partially autonomous, and fully autonomous unmanned ships [6, 8]. The adoption of Information and Communications Technology (ICT) in the shipping industry is certainly accompanied by an explosion of cyber risks, with existing risks being increased and new risks being introduced [9]. Therefore, ensuring the safety and security of an autonomous ship cannot be ensured, and it is not possible to rely on previous system knowledge [2, 3, 6]. Instead, itnecessitates a novel security approach, which considers all of the various systems onboard and onshore, as well as how they interact [2, 3, 9, 10].  
According to the European Directive \"EU 2016-679\", cyber-enabled ships are among the most critical infrastructures that already rely heavily on digital services, while malicious disruption of their operations can lead to financial and environmental damage or even endanger human safety [7]. Although some research is being conducted in this area [2, 3, 6, 9, 11], maritime cybersecurity has not been deeply investigated. In this paper, we first identify security issues and threats that the modern shipping industry is facing, especially those targeting the systems available on ships. Then, we describe possible mitigation actions that can be utilised in advance to prevent such attacks, and finally, we discuss several challenges and open problems for future research. The remainder of this article is structured as follows: the next section (Section 2) provides the background of the main systems available on modern and autonomous ships that could be targeted by attackers, while Section 3 presents the possible vulnerabilities and major security threats of these systems. Section 4 presents and discusses actual reported incidents in the last few years. Available security countermeasures and possible mitigation actions are discussed in Section 5, and finally, Section 6 concludes the paper and outlines directions for future research.