Internet of Things (IoT) generally referred as Industry 4.0, Now a day's Application Areas are everywhere like Smart Transportation, Smart Construction, Fitness monitoring, Energy Supervision, Construction managing, Environmental Supervise, Groceries supply chain. IoT has a compound network of smart nodes; information sending and receiving of nodes are through the Internet. In this process, it is vulnerable to attacks. In This paper, we review the possible attacks with respect to Cisco-Seven Layer model.