A worrying number of VPN apps for Android mobile devices are rife with malware, spying, and code injection, say researchers.
A study [PDF] from CSIRO Data61 in Australia, the University of New South Wales in Australia and the University of California at Berkeley found that Android apps advertising themselves as VPN clients often contain poor security protections, and in some cases engage in outright malicious activities.
"Many apps may legitimately use the VPN permission to offer (some form of) online anonymity or to enable access to censored content," the researchers write. "However, malicious app developers may abuse it to harvest users' personal information."
That sort of malicious activity is shockingly common, the researchers found. They studied the activity of 283 VPN apps on the Google Play store and catalogued the various risky and malicious activities they found:
- 82 per cent of the VPN apps requested permission to access sensitive data on the device, such as SMS history.
- 38 per cent of the apps contained some form of malware.
- 16 per cent routed traffic through other devices, rather than a host server.
- 16 per cent use in-path proxies to modify HTML traffic in transit.
- Three of the 283 analysed apps specifically intercept bank, messaging, and social network traffic.
"Our results show that – in spite of the promises for privacy, security and anonymity given by the majority of VPN apps – millions of users may be unawarely subject to poor security guarantees and abusive practices inflicted by VPN apps," the researchers noted.
The study concluded that, in addition to users being wary in their choice of VPN apps and keeping a close eye on permissions, Google should look to help remedy the situation by setting stricter limits on what VPN apps are able to do in Android.
"The ability of the BIND_VPN_SERVICE permission to break Android's sandboxing and the naive perception that most users have about third-party VPN apps suggest that it is urging [sic] to re-consider Android's VPN permission model to increase the control over VPN clients," they said.
"Our analysis of the user reviews and the ratings for VPN apps suggested that the vast majority of users remain unaware of such practices even when considering relatively popular apps."
So, if you're shopping for a VPN client, what should you do? Well, a little research goes a long way: check reviews and recommendations, and steer clear of overreaching applications.
"Always pay attention to the permissions requested by apps that you download," said Professor Dali Kaafar, a senior researcher at CSIRO, the Australian government's boffinry nerve center. "This study shows that VPN app users, in particular, should take the time to learn about how serious the issues with these apps are and the significant risks they are taking using these services.”
The researchers' paper doesn't list all the apps it tried, which is a little frustrating. However, it does call out EasyOvpn, VPN Free, Tigervpns, DNSet, CM Data Manager, Rocket VPN, Globus VPN, Spotflux VPN and CyberGhost, as "malicious or intrusive." OkVpn, EasyVpn, SuperVPN, Betternet, CrossVpn, Archie VPN, HatVPN, sFly Network Booster, One Click VPN, and Fast Secure Payment, are also flagged up as containing malware in the VirusTotal database.
Open Gate, VPN Gate, and VyprVPN get a slap for using home broadband connections as egress points, and Tigervpns, StrongVPN, and HideMyAss raised suspicions after exogenous traffic was spotted from them.
Finally, we've heard nice things about Algo, if you're looking to set up your own VPN. ®