PoisonCatcher: Revealing and Identifying LDP Poisoning Attacks in IIoT

Local Differential Privacy (LDP) is widely adopted in the Industrial Internet of Things (IIoT) for its lightweight, decentralized, and scalable nature. However, its perturbation-based privacy mechanism makes it difficult to distinguish between uncontaminated and tainted data, encouraging adversaries to launch poisoning attacks. While LDP provides some resilience against minor poisoning, it lacks robustness in IIoT with dynamic networks and substantial real-time data flows. Effective countermeasures for such attacks are still underdeveloped. This work narrows the critical gap by revealing and identifying LDP poisoning attacks in IIoT. We begin by deepening the understanding of such attacks, revealing novel threats that arise from the interplay between LDP indistinguishability and IIoT complexity. This exploration uncovers a novel rule-poisoning attack, and presents a general attack formulation by unifying it with input-poisoning and output-poisoning. Furthermore, two key attack impacts, i.e., Statistical Query Result (SQR) accuracy degradation and inter-dataset correlations disruption, along with two characteristics: attack patterns unstable and poisoned data stealth are revealed. From this, we propose PoisonCatcher, a four-stage solution that detects LDP poisoning attacks and identifies specific contaminated data points. It utilizes temporal similarity, attribute correlation, and time-series stability analysis to detect datasets exhibiting SQR accuracy degradation, inter-dataset disruptions, and unstable patterns. Enhanced feature engineering is used to extract subtle poisoning signatures, enabling machine learning models to identify specific contamination. Experimental evaluations show the effectiveness, achieving state-of-the-art performance with average precision and recall rates of 86.17% and 97.5%, respectively, across six representative attack scenarios.