## 2 Background
### Cybersecurity in IoUT  
Nowadays, the term \"communication\" is implicitly linked to security. The technological advancements that are taking place every day in numerous domains, such as industrial IoT, digital twins, 3D printing, quantum computing, security blockchain, etc., have exponential growth. Upcoming trends such as 5G, IoT connectivity, Cloud computing, etc., are becoming part of our daily life. However, the major issue of this rapid technological development is the difficulty, in most cases, to follow along [43]. The tremendous development of information and communication technologies (ICTs) and automation of mostprocesses in our daily life, improve mobility by offering a variety of services to a vast number of users [44]. However, vulnerabilities are raised even more, impacting users directly from the security perspective. The principal issue concerns non-awareness of the power of constantly emerging trends and the fact that users cannot perceive their function. Undoubtedly, the weakest link in defense against cyberattacks is the human being [45]. Internet of Things (IoT) in combination with 5G can connect huge number of devices with huge speeds, but the majority are not aware of the potential threats this facilitation seeks. This increases the number of potential access points for cybercriminals [46], and a great example is the era of COVID-19, in which remote work constantly raised extreme risks. From free-access hotspots to personal devices, adversaries can find a path to exploit them and extract our personal data; in fact, according to the UK National Cyber Security Centre, in the first quarter of 2021, there were three times as many ransomware attacks as in the whole of 2019 [46]. Numerous security issues and vulnerabilities are emerging regularly, in networks across all domains. Unfamiliarity with technology, is one of numerous and various reasons security systems fail to detect and defend against sophisticated attacks. Statistics from IBM's Cost of a Data Breach Report 2021 [47] indicate that the average cost of a data breach increased by 1.07 million USD in 2021. Furthermore, according to ENISA's (European Network and Information Security Agency) Threat Landscape 2021 [48], DDoS attacks, a denial-of-service attack that malfunctions a network, have shown an upward tendency the last two years. Additionally, an infamous (in the cybersecurity community) virus named Emotet botnet, one of the longest-running and most widespread malware threats which is spread through spam emails, dealt a major blow, due to its enormous impact, especially in Windows administration and control servers [47]. Adversaries from \"script kiddies\" to the experienced can perform devastating attacks; most of these attacks concern networks and communication protocols between the host and the server. However, innovative tools can utilize new technologies to counter cybercrime. AI-powered cybersecurity for example, can predict vulnerabilities and identify suspect patterns, to alert incident responders for possible attacks. Thus, an interesting project, known as AIDA [49], utilizes artificial intelligence (AI) combined with machine learning (ML), in order to establish effective data analytics. Consequently, by developing big data analysis and an analytics framework equipped with automated data mining to deal with information extraction and knowledge management, they contribute to counter cybercrime. The project is expected to be completed by the third quarter of 2022. Vulnerabilities and cyber threats exist across all domains, and it is undoubtedly irrational to deny their existence as well in the domain of IoUT. To ensure the security of the underwater domain, robust security systems equipped with effective frameworks and semantic knowledge are a recommended solution, offering suitable methods for \"uncharted\" behavior; the main issue of the cybersecurity domain [50]. Attack methodologies and tools are becoming more and more sophisticated, generating the need for determination of the specific steps of an attack.