The Null Device
A group of hackers in Germany have built a device disguised as a wall-mounted power supply which connects to wireless networks, intercepts packets and subtly changes the content of pages from news websites:
The Newstweek uses ARP spoofing to change the text displayed on several news sites. After doing some field research, placing and configuring the device, there’s a simple web frontend that configures the man-in-the-middle hack. Right now, the Newstweek only allows a few news sites to be targeted, but the team is working on allowing anyone to add their own targets.There is a technical walkthrough of its construction here. Unsurprisingly, it's basically a Linux-based wireless access point, hacked into a new case and running a customised version of the OpenWRT firmware.
Meanwhile, Charlie Stross extrapolates on more serious applications of such technologies:
This sort of gadget is, in bulk, extremely cheap — I bet you could order them for well under $100 in batches of a thousand and up. Say you're a repressive regime, but not so repressive that you can just haul random dissidents off to the torture chamber without paying lip service to due process. How hard would it be to plant these things in your targets' homes, so that you can gaslight them by interfering with the news they're reading? Call it a digital agent provocateur. Say you're the DHS and you want a steady stream of clueless Al Qaida wannabes to arrest and show on CNN to keep everyone afraid enough to go along with your PATRIOT Act extension? Plant these in the homes of young muslim males who hang out at the wrong mosques, crank up the volume of hateful news, and see who snaps ...