<p style="text-align:justify;"><span style="font-size:medium;color:#3300ff;"><strong>Abstract </strong></span></p><p style="text-align:justify;">Internet of Things (IoT) devices are rapidly becoming ubiquitous while IoT services are becoming pervasive. Their success has not gone unnoticed and the number of threats and attacks against IoT devices and services are on the increase as well. Cyber-attacks are not new to IoT, but as IoT will be deeply interwoven in our lives and societies, it is becoming necessary to step up and take cyber defense seriously. Hence, there is a real need to secure IoT, which has consequently resulted in a need to comprehensively understand the threats and attacks on IoT infrastructure. This paper is an attempt to classify threat types, besides analyze and characterize intruders and attacks facing IoT devices and services. </p><p style="text-align:justify;"><strong>Keywords:</strong> Internet of Things, Cyber-attack, Security threats.</p><p style="text-align:justify;"><span style="color:#3300ff;font-size:medium;"><strong>1 Introduction </strong></span></p><p style="text-align:justify;">The recent rapid development of the Internet of Things (IoT) [1, 2] and its ability to offer different types of services have made it the fastest growing technology, with huge impact on social life and business environments. IoT has</p>