On the Robustness of Clustering Algorithms to Adversarial Attacks

Machine learning is becoming more and more used by businesses and private users as an additional tool for aiding in decision making and automation processes. However, over the past few years, there has been an increased interest in research related to the security or robustness of learning models in presence of adversarial examples. It has been discovered that wisely crafted adversarial perturbations, unaffecting human judgment, can significantly affect the performance of the learning models. Adversarial machine learning studies how learning algorithms can be fooled by crafted adversarial examples. In many ways it is a recent research area, mainly focused on the analysis of supervised models, and only few works have been done in unsupervised settings. The adversarial analysis of this learning paradigm has become imperative as in recent years unsupervised learning has been increasingly adopted in multiple security and data analysis applications. In this thesis, we are going to show how an attacker can craft poisoning perturbations on the input data for reaching target goals. In particular, we are going to analyze the robustness of two fundamental applications of unsupervised learning, feature-based data clustering and image segmentation. We are going to show how an attacker can craft poisoning perturbations against the two applications. We choose 3 very well known clustering algorithms (K-Means, Spectral and Dominant Sets clustering) and multiple datasets for analyzing the robustness provided by them against adversarial examples, crafted with our designed algorithms.