# Security Issues in IoT-Based Wireless Sensor Networks: Classifications and Solutions
###### Abstract
With the diversity of modern attack models, continuously updating and enhancing security measures becomes the key to building and ensuring safe, efficient, and reliable WSN-IoT applications [13; 14]. [PERSON] et al. [15] studied the development, applications and challenges faced by IoT systems. The security issues in IoTs were analyzed through a multi-layered perspective, thereby proposing secure data transmission solutions for WSN-based IoT applications. [PERSON] et al. [16] proposed solutions to improve IoT security and abnormal detection methods. They were compared with state-of-the-art intrusion detection systems (IDSs). [PERSON] et al. performed a comprehensive analysis of security challenges and potential threats in IoT applications [17], thereby proposing solutions to improve IoT infrastructure to support secure interactions. Device security, transmission security, and data security are all included in the security classification criteria of [PERSON] et al. [18] to evaluate IoT security. In IoTs, some types of attacks can be mitigated by using authentication techniques and lightweight encryption algorithms. [PERSON] et al. [19] emphasized vulnerabilities that can lead to security breaches and identified common threats and attack routes on IoT devices. The study also provides some security enhancements and preventive techniques to mitigate the risks, along with remediation measures for compromised devices. To enhance the security effectiveness in WSN-IoT, some other authors have proposed the use of technologies such as machine learning, edge computing, cloud computing, and blockchain to improve IoT security. In the study of [PERSON] et al. [20], an intrusion prevention framework for mobile IoT devices and integration with WSNs was proposedto provide data security with an improved network distribution ratio. Machine learning techniques are proven to be effective in WSN-IoT due to their intelligent and cost-effective computational procedures. In some recent studies [21; 22; 23; 24], the authors have discussed machine learning algorithms to improve security performance, such as congestion-based intrusion detection in WSN-IoT. The above-mentioned studies have highlighted the prominent WSN-IoT security attacks in recent years, based on criteria such as attack targets, technologies used, impact level, feasibility, and contribution to overall WSN-IoT security solutions. However, there are still gaps in these studies, especially in thoroughly analyzing attacks from a security perspective for WSNs while integrated with the IoT. Therefore, the corresponding security methods need to be comprehensively considered based on criteria such as cost optimization, resource efficiency, energy saving, and system availability assurance. In addition, other proposed solutions are also considered, including data aggregation methods, intrusion detection and trust modeling methods, and methods based on new technologies such as blockchain. Since there are many results related to security problems and solutions are considered separately in the fields, it is necessary to present some work that either leads to addressing the problems in some classifications or provides solutions corresponding to problems. The objective of this paper is to address these issues through the following research objectives and research questions (RQs), as shown in Figure 1.  
In this paper, through a comprehensive review of the literature and a detailed analysis of the prominent WSN-IoT-related security attacks in recent years, the importance of WSN-IoT systems is highlighted based on their applications in various fields. Security issues in WSN-IoT systems are reviewed and related security attacks are classified in detail. The corresponding security solutions are proposed, compared, and evaluated to mitigate security attacks, threats, and vulnerabilities in WSN-IoT systems. In addition, we outline key security limitations and challenges, and present future research directions based on emerging application areas. The rest of this paper is organized as follows.