In the past decade, the popularity of VPNs has risen due to increased concerns about privacy and surveillance. Some governments are trying to block VPN access by using advanced technology to detect VPN connections. Through our research, we have developed a framework that can accurately identify connections using OpenVPN, the most commonly used protocol for commercial VPN services. Our findings show that over 85% of OpenVPN flows can be detected with minimal false positives, making it possible to block OpenVPN-based services effectively. Despite some VPNs implementing measures to evade detection, our framework successfully identified connections to the majority of “obfuscated” VPN configurations. We discuss the implications of VPN fingerprinting and suggest solutions for both short-term and long-term defenses.
https://arxiv.org/abs/2403.03998