Understanding the Proxy Ecosystem: A Comparative Analysis of Residential and Open Proxies on the Internet

Proxy servers act as an intermediary and a gateway between users and other servers on the Internet, and have many beneficial applications targeting the privacy of users, including bypassing server-side blocking, regional restrictions, etc. Despite the beneficial applications of proxies, they are also used by adversaries to hide their identity and to launch many attacks. As such, many websites restrict access from proxies, resulting in blacklists to filter out those proxies and to aid in their blocking. In this work, we explore the ecosystem of proxies by understanding their affinities and distributions comparatively. We compare residential and open proxies in various ways, including country-level and city-level analyses to highlight their geospatial distributions, similarities, and differences against a large number of blacklists and categories therein, i.e., spam and maliciousness analysis, to understand their characteristics and attributes. We conclude that, while aiming to achieve the same goal, residential and open proxies still have distinct characteristics warranting considering them separately for the role they play in the larger Internet ecosystem. Moreover, we highlight the correlation of proxy locality distribution and five country-level characteristics, such as their Internet censorship, political stability, and Gross Domestic Product (GDP).