Undetectable Cyber Attacks on Communication Links in Multi-Agent Cyber-Physical Systems

TL;DR

This paper analyzes undetectable cyber attacks in multi-agent cyber-physical systems, classifies attack types, introduces a novel quasi-covert attack, and proposes an event-triggered detector to identify such attacks.

Contribution

It develops conditions for undetectable attacks, introduces a new quasi-covert attack concept, and proposes an event-triggered detection method for these cyber threats.

Findings

Undetectable attacks occur when root agents are compromised.

Non-root agent attacks can become detectable under certain conditions.

The proposed detector effectively identifies quasi-covert cyber attacks.

Abstract

The objective in this paper is to study and develop conditions for a network of multi-agent cyber-physical systems (MAS) where a malicious adversary can utilize vulnerabilities in order to ensure and maintain cyber attacks undetectable. We classify these cyber attacks as undetectable in the sense that their impact cannot be observed in the generated residuals. It is shown if an agent that is the root of a rooted spanning tree in the MAS graph is under a cyber attack, the attack is undetectable by the entire network. Next we investigate if a non-root agent is compromised, then under certain conditions cyber attacks can become detectable. Moreover, a novel cyber attack that is designated as quasi-covert cyber attack is introduced that can be used to eliminate detectable impacts of cyber attacks to the entire network and maintain these attacks as undetected. Finally, an event-triggered based detector is proposed that can be used to detect the quasi-covert cyber attacks. Numerical simulations are provided to illustrate the effectiveness and capabilities of our proposed methodologies.