A Glance through the VPN Looking Glass: IPv6 Leakage and DNS Hijacking in Commercial VPN clients

Abstract

Commercial Virtual Private Network (VPN) services have become a popular and convenient technology for users seeking privacy and anonymity. They have been applied to a wide range of use cases, with commercial providers often making bold claims regarding their ability to fulfil each of these needs, e.g., censorship circumvention, anonymity and protection from monitoring and tracking. However, as of yet, the claims made by these providers have not received a sufficiently detailed scrutiny. This paper thus investigates the claims of privacy and anonymity in commercial VPN services. We analyse 14 of the most popular ones, inspecting their internals and their infrastructures. Despite being a known issue, our experimental study reveals that the majority of VPN services suffer from IPv6 traffic leakage. The work is extended by developing more sophisticated DNS hijacking attacks that allow all traffic to be transparently captured.We conclude discussing a range of best practices and countermeasures that can address these vulnerabilities

MassBrowser: Unblocking the Censored Web for the Masses, by the Masses

“…Proxy-based Systems The most common approach used by circumvention systems is to run network proxies outside the censorship region, and use them to relay the traffic of censored users to censored Internet destinations. Many in-thewild circumvention systems such as Tor [15], Psiphon [58], Lantern [40], and VPN services [56], [52] deploy circumvention proxies in different ways to help censored users. Most circumvention systems [58], [67], [52], [40] use simple, singlehop proxies, while others [15], [57] use more complex models for proxy deployment.…”

MoneyMorph: Censorship Resistant Rendezvous using Permissionless Cryptocurrencies

“…The traditional censorship circumvention systems such as VPNs [55,57], Dynaweb [10], Ultrasurf [24], Lantern [13], Tor [32], and others [33] benefit from establishing proxy servers outside of the censored area. However, these systems are vulnerable to blockage.…”

Investigation into the security and privacy of iOS VPN applications

“…The paper covered a large dataset of 283 applications, but only focused on VPN clients within the Android operating system. A Glance through the VPN Looking Glass [6] is another piece of VPN security research that investigated a significantly smaller dataset (just 14 VPN clients) but clients were analyzed on every common operating system (iOS, Android, Windows, OS X and Linux). The research involves testing the selection of VPN clients for known security issues within VPN clients (such as IPv6 leakage and DNS leakage).…”

“…Due to a lack of support by some VPN clients, IPv6 requests are routed outside of the secure VPN tunnel, potentially leaking user information. This issue is also detailed in A Glance through the VPN Looking Glass [6].…”