Characterizing the VPN Ecosystem in the Wild

With the increase of remote working during and after COVID-19 pandemic, use Virtual Private Networks (VPNs) around world has nearly doubled. Therefore, measuring traffic security aspects VPN ecosystem is more important now than ever. users rely on solutions, to protect private corporate communication. Thus a good understanding state servers crucial. Moreover, properly detecting characterizing remains challenging, since some protocols same port number as web port-based classification will not help. In this paper, we aim at in wild, which facilitates traffic. To end, perform Internet-wide active measurements find analyze their cryptographic certificates, vulnerabilities, locations, fingerprints. We 9.8M distributed using OpenVPN, SSTP, PPTP, IPsec, vulnerability. SSTP be most vulnerable protocol with 90% detected being TLS downgrade attacks. Out all that respond our probes, 2% also HTTP probes therefore are classified Web servers. Finally, list identify large European ISP observe 2.6% related these