## 1 Introduction
Keys can be compromised, devices with weak malware protections can be used as \"bots\" to forward malicious codes to infest other devices and the entire network can be intruded on. A recent HP study reveals that 70% of IoT devices are vulnerable to various forms of cyberattacks [14]. Thus, strong encryption and authentication of the application payload and the network admission request, etc. are some of the methodology proposed in the literature. The threats, effects and impacts of LPWAN security menaces have been extensively discussed in numerous studies [15; 16; 17; 18]. To mitigate the growing IoT and LPWAN security challenges, numerous security solutions such as intrusion detection systems (IDSs), key management and encryption schemes have been proposed in the literature [19; 20; 21; 22]. Despite the satisfactory performances demonstrated, some of the various schemes and upgrades from the standard producers have struggled in addressing the emerging security requirements of the IoT operational environment, e.g., despite LoRaWAN's specification that laid emphasis on key management protocol whereby a compromised key from an end node should not create a major problem for other nodes, experiences have shown that key management issues is still a major problem with regards to the standard. Thus, there is a need to present efficient and effective security solutions that can urgently detect and mitigate LPWAN attacks and vulnerabilities. Focusing on analyzing LPWAN's key cybersecurity architectural framework and technical features, a comprehensive review of the most recent research works that discussed the security aspect of LPWAN is presented in this paper. The paper aims at summarizing recent research methodologies on key LPWAN security challenges and varieties of threats, the effect of the attacks, and most importantly the various approaches proposed in the literature for the attacks' mitigations. The main contributions of the paper are stated briefly as follows:  
* We present a comprehensive review of the security and privacy issues and attacks that affect LPWAN. The attacks are categorized under the prominent information security requirements known as Confidentiality, Integrity, and Availability (CIA triad);* a detailed analysis of the different techniques and security solutions that have been proposed in the literature for securing LPWAN are extensively discussed. The analysis entails a comparison of the mitigation methodologies, the types of attacks mitigated, the security requirements and limitations; and
* challenges and research gap in existing LPWAN security methods and the direction for future works are broadly analyzed. Accordingly, the reminder of the paper is organized as follows: The related works on IoT and LPWAN is presented in Section 2. Section 3 presents an overview of the LPWAN. Section 4 presents the LPWAN technologies. Section 5 presents a brief security analysis of LPWAN. The section discusses the vulnerabilities and threats attributed to LPWAN. In Section 6, we discuss and compare some of the proposed techniques in the literature for mitigating attacks in LPWAN. The research challenges and recommendations for future works are discussed in Section 7. Lastly, Section 8 presents the conclusion.