In this paper we present a model-based intrusion detection system (IDS) for home area networks (HANs) within the smart grid. Considering that ZigBee is the dominant technology in future HAN, the proposed IDS is designed to target ZigBee standard. Our focus is on the physical and medium access control (MAC) layers of ZigBee technology, which are defined in IEEE 802.15.4 standard. In the proposed IDS, normal behavior of the network is modeled through specifications extracted from the IEEE 802.15.4 standard as well as features of wireless network traffic. Deviations from normal behavior can be a sign of malicious activities. We use Bayesian network as a classifier to distinguish the normal and malicious behavior of the network according to extracted features. We further investigate the physical and MAC layer attacks in IEEE 802.15.4 networks that have been introduced in literature. In order to evaluate the performance of the proposed method we simulate a HAN network as well as some attack scenarios, in NS-2 simulation environment. We evaluate the performance of the proposed IDS against these attacks. Analysis and simulation results demonstrate that the proposed IDS provides good detection performance against known attacks, and since this is an IDS based on anomalous event detection, we expect the same for unknown attacks.
KeywordsHAN, IDS, smart grid
I TRODUCTIOSmart grid is a vision to modernize the electricity transmission and distribution systems. Smart grid incorporates computer intelligence into the power system, and provides two way energy flow and data communication. Unlocking the tremendous potential of the smart grid such as resilience, high power quality, and consumer participation, strongly depends on the security of this system. Integration of a data layer to the power grid can expose the system to many cyber security threats. Smart grid is an infrastructure that many other utilities rely on; without strong security measures, not only the smart grid will inherit the vulnerabilities of the legacy power system, but also new vulnerabilities will be added due to the proliferation of new technologies.In the 2009 White House Cyberspace Policy Review, federal government was asked to "ensure that security standards are developed and adopted to avoid creating unexpected opportunists to penetrate these systems or conduct large-scale attacks" [1]. The US National Institute of Standards and Technology (NIST) has provided guidelines for developers and policy makers, covering cyber security requirements of the smart grid that should be included from the beginning of the development process [2]. Along with the security mechanisms that should be designed into the smart grid with the goal of reducing the vulnerabilities and mitigating their consequences, such as cryptographic algorithms and secure protocols, appropriate intrusion detection systems (IDSs) are also required. The need for research on intrusion detection for embedded processors has been emphasized in "NIST guidelines for smart grid cyber security", ...