This paper aims at investigating a novel type of cyber attack that is injected to multi-agent systems (MAS) having an underlying directed graph. The cyber attack, which is designated as the controllability attack, is injected by the malicious adversary into the communication links among the agents. The adversary, leveraging the compromised communication links disguises the cyber attack signals and attempts to take control over the entire network of MAS. The adversary aims at achieving this by directly attacking only a subset of the multi-agents. Conditions under which the malicious hacker has control over the entire MAS network are provided. Two notions of security controllability indices are proposed and developed. These notions are utilized as metrics to evaluate the controllability that each agent provides to the adversary for executing the malicious cyber attack. Furthermore, the possibility of introducing zero dynamics cyber attacks on the MAS through compromising the communication links is also investigated. Finally, an illustrative numerical example is provided to demonstrate the effectiveness of our proposed methods.

中文翻译：

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多代理系统在通信链路上遭受恶意网络攻击的缓解和弹性

本文旨在研究一种新型的网络攻击，该攻击注入具有底层有向图的多代理系统 (MAS)。被称为可控性攻击的网络攻击是由恶意对手注入代理之间的通信链路。攻击者利用受损的通信链路伪装网络攻击信号，并试图控制 MAS 的整个网络。对手的目标是通过直接攻击多智能体的一个子集来实​​现这一目标。提供了恶意黑客控制整个 MAS 网络的条件。安全可控指标的两个概念被提出和发展。这些概念被用作衡量每个代理为执行恶意网络攻击提供给对手的可控性的指标。此外，还研究了通过破坏通信链路对 MAS 引入零动态网络攻击的可能性。最后，提供了一个说明性的数值例子来证明我们提出的方法的有效性。