This paper proposes a distributed attack detection and mitigation technique based on distributed estimation over a multi-agent network, where the agents take partial system measurements susceptible to (possible) biasing attacks. In particular, we assume that the system is not locally observable via the measurements in the direct neighborhood of any agent. First, for performance analysis in the attack-free case, we show that the proposed distributed estimation is unbiased with bounded mean-square deviation in steady-state. Then, we propose a residual-based strategy to locally detect possible attacks at agents. In contrast to the deterministic thresholds in the literature assuming an upper bound on the noise support, we define the thresholds on the residuals in a probabilistic sense. After detecting and isolating the attacked agent, a system-digraph-based mitigation strategy is proposed to replace the attacked measurement with a new observationally-equivalent one to recover potential observability loss. We adopt a graph-theoretic method to classify the agents based on their measurements, to distinguish between the agents recovering the system rank-deficiency and the ones recovering output-connectivity of the system digraph. The attack detection/mitigation strategy is specifically described for each type, which is of polynomial-order complexity for large-scale applications. Illustrative simulations support our theoretical results.
Detection and Mitigation of Biasing Attacks on Distributed Estimation Networks
The University of Melbourne（墨尔本大学）；University of New South Wales at the Australian Defence Force Academy（新南威尔士大学澳大利亚国防军学院）；University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）
Detection of Biasing Attacks on Distributed Estimation Networks
University of New South Wales at the Australian Defence Force Academy（新南威尔士大学澳大利亚国防军学院）；University of Melbourne（墨尔本大学）；University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）
Optimal Attack against Cyber-Physical Control Systems with Reactive Attack Mitigation
Advanced Digital Sciences Center, Illinois at Singapore（伊利诺伊大学新加坡先进数字科学中心）；GovTech Singapore（新加坡政府科技局）；Singapore University of Technology and Design（新加坡科技设计大学）；Nanyang Technological University（南洋理工大学）
Performance and Resilience of Cyber-Physical Control Systems with Reactive Attack Mitigation
University of Warwick（华威大学）；Oracle India Pvt. Ltd.（甲骨文印度私人有限公司）；GovTech Singapore（新加坡政府科技局）；Nanyang Technological University（南洋理工大学）；Singapore University of Technology and Design（新加坡科技设计大学）
