Biblio
Although 6LoWPAN has brought about a revolutionary leap in networking for Low-power Lossy Networks, challenges still exist, including security concerns that are yet to answer. The most common type of attack on 6LoWPANs is the network layer, especially routing attacks, since the very members of a 6LoWPAN network have to carry out packet forwarding for the whole network. According to the initial purpose of IoT, these nodes are expected to be resource-deficient electronic devices with an utterly stochastic time pattern of attachment or detachment from a network. This issue makes preserving their authenticity or identifying their malignity hard, if not impossible. Since 6LoWPAN is a successor and a hybrid of previously developed wireless technologies, it is inherently prone to cyber-attacks shared with its predecessors, especially Wireless Sensor Networks (WSNs) and WPANs. On the other hand, multiple attacks have been uniquely developed for 6LoWPANs due to the unique design of the network layer protocol of 6LoWPANs known as RPL. While there exist publications about attacks on 6LoWPANs, a comprehensive survey exclusively on RPL-specific attacks is felt missing to bold the discrimination between the RPL-specific and non-specific attacks. Hence, the urge behind this paper is to gather all known attacks unique to RPL in a single volume.
A significant segment of the Internet of Things (IoT) is the resource constrained Low Power and Lossy Networks (LLNs). The communication protocol used in LLNs is 6LOWPAN (IPv6 over Low-power Wireless Personal Area Network) which makes use of RPL (IPv6 Routing Protocol over Low power and Lossy network) as its routing protocol. In recent times, several security breaches in IoT networks occurred by targeting routers to instigate various DDoS (Distributed Denial of Service) attacks. Hence, routing security has become an important problem in securing the IoT environment. Though RPL meets all the routing requirements of LLNs, it is important to perform a holistic security assessment of RPL as it is susceptible to many security attacks. An important attribute of RPL is its rank property. The rank property defines the placement of sensor nodes in the RPL DODAG (Destination Oriented Directed Acyclic Graphs) based on an Objective Function. Examples of Objective Functions include Expected Transmission Count, Packet Delivery Rate etc. Rank property assists in routing path optimization, reducing control overhead and maintaining a loop free topology through rank based data path validation. In this paper, we investigate the vulnerabilities of the rank property of RPL by constructing an Attack Graph. For the construction of the Attack Graph we analyzed all the possible threats associated with rank property. Through our investigation we found that violation of protocols related to rank property results in several RPL attacks causing topological sub-optimization, topological isolation, resource consumption and traffic disruption. Routing security essentially comprises mechanisms to ensure correct implementation of the routing protocol. In this paper, we also present some observations which can be used to devise mechanisms to prevent the exploitation of the vulnerabilities of the rank property.