On Man-in-the-Middle Attack Risks of the VPN Gate Relay System

With the development of the Internet, more and more people use virtual private network (VPN) to circumvent censorship or hide themselves for privacy purposes. However, VPN itself faces some security and privacy risks. Widely used all over the world, the VPN Gate is a volunteer-organized public VPN relay system launched in 2013. By analyzing the security of the system, we have found that there is a man-in-the-middle attack risk because an attacker may hijack a VPN session and decrypt the traffic. According to our study, the reason of the security issues is the misuse of the SSL certificate. To mitigate the security risks, we offered a series of recommendations.