The Internet of Things (IoT) represents a modern approach where boundaries between real and digital domains progressively eliminated by changing over consistently every physical device to smart object. Each of these smart objects play a role in different life domains but at the same time create new challenges. The glue that binds IoT systems and their actors or devices will provide a mechanism for risk propagation and creation of harm, particularly in security and privacy, at physical, social, and economic scales. As such, the IoT actor, if repurposed, might be able to facilitate harms far beyond what is expected. Estimating risk is a complex operation that requires the consideration of a variety of factors. Moreover, the interpretation and estimation of the risk might vary depending on the working domain. This needs to be considered in a new risk assessment approach, as the inability of periodic assessment to respond to dramatic changes in IoT environments. This paper presents a review of different risk assessment techniques.