Analysis and prediction of web proxies misbehavior

The need for anonymity and privacy has given a rise to open web proxies that act as gateways relaying traffic between web servers and their clients, allowing users to access otherwise not accessible content. As the open web proxy ecosystem continues to grow, research studies point out the extent of content alteration on the Internet. While the previous studies focused on detection and analysis of content manipulation by proxies, we focus on the feasibility of predicting these manipulations. In this work, we present a new approach for predicting the types of content alterations that might be silently introduced by open proxies. Our approach is designed to proactively indicate changes without a need to fetch the data through a proxy first. We explore the feasibility of the approach on a website content of 1028 domains fetched through 1293 proxies. We leverage our approach to proactively and accurately identify various content manipulations with 87% - 92% accuracy. Our study reveals an important observation that the majority of proxies manipulate website content based on technical information of the website and its web server.