Last weekend saw the announcement of ProxyHam, a device that anonymizes Internet activity by jumping on WiFi from public libraries and cafes over a 900MHz radio link. The project mysteriously disappeared and was stricken from the DEFCON schedule. No one knows why, but we spent some time speculating on that and on what hardware was actually used in the undisclosed build.
[Samy Kamkar] has just improved on the ProxyHam concept with ProxyGambit, a device that decouples your location from your IP address. But [Samy]’s build isn’t limited to ProxyHam’s claimed two-mile range. ProxyGambit can work anywhere on the planet over a 2G connection, or up to 10km (6 miles) away through a line-of-sight point to point wireless link.
The more GSM version of ProxyGambit uses two Adafruit FONA GSM breakout boards, two Arduinos, and two Raspberry Pis. The FONA board produces an outbound TCP connection over 2G. The Arduino serves as a serial connection over a reverse TCP tunnel and connects directly to the UART of a Raspberry Pi. The Pi is simply a network bridge at either end of the connection. By reverse tunneling a TCP connection through the ‘throwaway’ part of the build, [Samy] can get an Internet connection anywhere that has 2G service.
Although it’s just a proof of concept and should not be used by anyone who actually needs anonymity, the ProxyGambit does have a few advantages over the ProxyHam. It’s usable just about everywhere on the planet, and not just within two miles of the public WiFi access point. The source for ProxyGambit is also available, something that will never be said of the ProxyHam.