Developing a secured information processing environment highly depends on securing all of the layers and devices in the environment. Edge/Fog computing environments are not an exception in this case, and the security of those environments highly depends on securing the Internet of Things (IoT) devices which are the most vulnerable devices through the environment. The adoption of Edge/Fog computing paradigms by new emerging technologies stimulated malware development for IoT platforms. Recent attacks initiated by IoT malware show that these attacks make a tremendous impact on compromised systems in terms of Quality of Service because of the number of infected IoT devices. In the light of these developments, there is an enormous need for efficient solutions. However, defense capability against these new malware types is highly constrained by the limited understanding of these new emerging paradigms and the lack of access to malware samples. This paper mainly focuses on IoT malware to understand the behaviors of malware on the most vulnerable layer of the Edge/Fog computing environments. Mainly, 64 IoT malware families are located from 2008 when the first known IoT malware emerged to October 2022. These malware families are systematically characterized from various aspects, including target architecture, target device, delivery methods, attack vectors, persistence techniques, and their evolution from existing malware. During this characterization process, two different investigation frameworks, "Cyber Kill Chain" and "Mitre ATT&CK for ICS," have been adopted in different investigation layers. This paper aims to bring light to future researches with presented features of the IoT malware.