How To Build A ProxyHam Despite A Cancelled DEFCON Talk

A few days ago, [Ben Caudill] of Rhino Security was scheduled to give a talk at DEFCON. His project, ProxyHam, is designed for those seeking complete anonymity online. Because IP addresses can be tied to physical locations, any online activities can be tracked by oppressive regimes and three letter government agencies. Sometimes, this means doors are breached, and “seditious” journalists and activists are taken into custody.

With the ProxyHam, the link between IP addresses and physical locations is severed. ProxyHam uses a 900MHz radio link to bridge a WiFi network over miles. By hiding a ProxyHam base station in a space with public WiFi, anyone can have complete anonymity online; if the government comes to take you down, they’ll first have to stop at the local library, Starbucks, or wherever else has free WiFi.

[Ben Caudill] will not be giving a talk at DEFCON. It wasn’t the choice of DEFCON organizers to cancel the talk, and it wasn’t his employers – [Ben] founded and is principal consultant at Rhino Security. The talk has been killed, and no one knows why. Speculation ranges from National Security Letters to government gag orders to a far more pedestrian explanations like, “it doesn’t work as well as intended.” Nevertheless, the details of why the ProxyHam talk was cancelled will never be known. That doesn’t mean this knowledge is lost – you can build a ProxyHam with equipment purchased from Amazon, Newegg, or any one of a number of online retailers.

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Turning the DEFCON Badge Into a Bitcoin Miner


The DEFCON badge this year was an impressive piece of hardware, complete with mind-bending puzzles, cap sense buttons, LEDs, and of course a Parallax Propeller. [mike] thought a chip as cool as the Propeller should be put to better use than just sitting around until next year so he turned it into a Bitcoin miner, netting him an astonishing 40 hashes per second.

Mining Bitcoins on hardware that doesn’t have much processing power to begin with (at least compared to the FPGAs and ASIC miners commonly used) meant [mike] would have to find some interesting ways to compute the SHA256 hashes that mining requires. He turned to RetroMiner, the Bitcoin miner made for an original Nintendo. Like the NES miner, [mike] is offloading the communication with the Bitcoin network to a host computer, but all of the actual math is handled by a single core on the Propeller.

Saving one core for communication with the host computer, a DEFCON badge could conceivably manage 280 hashes/second, meaning the processing power of all the badges made for DEFCON is about equal to a seven-year-old graphics card.

DEFCON: Blackphone

Despite being full of techies and people doing interesting things with portable devices, you don’t want to have an active radio on you within a quarter-mile of DEFCON. The apps on your phone leak personal data onto the Internet all the time, and the folks at DEFCON’s Wall Of Sheep were very successful in getting a few thousand usernames and passwords for email accounts.

Blackphone is designed to be the solution to this problem, so when we ran into a few members of the Blackphone crew at DEFCON, we were pretty interested to take a quick peek at their device.

The core functionality for the Blackphone comes from its operating system called PrivatOS. It’s a fork of Android 4.4.2 that is supposed to seal up the backdoors found in other mobile phones. There’s also a bundle of apps from Silent Circle that give the Blackphone the ability to make encrypted phone calls, texts (with file sharing), and encrypted and password protected contact lists.

The hardware for the Blackphone is pretty impressive; a quad-core Nvidia Tegra provides all the power you need for your apps, video, and playing 2048, a 2000mAh battery should provide enough juice to get you through a day or two (especially since you can turn off cores), and the usual front/rear cameras, GPS, 802.11bgn and GSM and HSPA+/WCDA radios means this phone will be useable on most networks.

Defcon Side Trip: Pololu And Robots

PololuDuring our trip out to Vegas for Defcon, we were lucky enough to catch up with a few of the companies that should be of interest to Hackaday readers. One of the companies based out of the area is Pololu, makers and purveyors of fine electronics and robots. In an incredible bit of lucky scheduling, LV Bots, the Las Vegas area robot builders club, was having an event the same weekend we were there. A maze challenge, no less, where builders would compete to build the best robot and write the best code to get a pile of motors and electronics through a line-following maze in the fastest amount of time.

The Bots

The LV Bots events are held in the same building as Pololu, and unsurprisingly there were quite a few Pololu employees making a go at taking the stuff they developed and getting it to run through a maze. At least one bot was based on the Zumo kit, and a few based on the 3pi platform. Interestingly, the Raspberry Pi Model B+ was the brains of quite a few robots; not extremely surprising, but evidence that the LV Bots people take their line-following mazes seriously and are constantly improving their builds.

Each robot and builder ‘team’ was given three runs. For each team, the first run is basically dedicated to mapping the entire maze. A carefully programmed algorithm tries to send the robot around the entire maze, storing all the intersections in memory. For the second and third runs, the bot should – ideally – make it to the end in a very short amount of time. This is the ideal situation and was only representative of one team for that weekend’s event.

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Fear and Loathing at DEFCON 22

Nothing says “Welcome to Vegas” like a massive turbulence on a plane full of drunk people who, instead of holding on to their seats, frantically laugh and shout “we’re all going to die!” At 105 Fahrenheit outside, the heat was getting into everyone’s head. After a bumpy touchdown, the in-flight entertainment system rebooted, and a black terminal screen flashed onto everyone’s face:

RedBoot(tm) bootstrap and debug environment [RAM]
(MAS eFX) release, version ("540060-212" v "0.1.02") - built 12:00:35,
Nov 19 2004

Now, that was a beautiful sight – an IFE system that hadn’t been updated for almost a decade. For people who didn’t come here to participate in a big zero-sum game that is Vegas, this was a sign.

DEFCON was waiting for us right outside of that front cabin door.

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Hat Hash Hacking at DEFCON

You probably remember that for DEFCON I built a hat that was turned into a game. In addition to scrolling messages on an LED marquee there was a WiFi router hidden inside the hat. Get on the AP, load any webpage, and you would be confronted with a scoreboard, as well as a list of usernames and their accompanying password hashes. Crack a hash and you can put yourself on the scoreboard as well as push custom messages to the hat itself.

Choosing the complexity of these password hashes was quite a challenge. How do you make them hackable without being so simple that they would be immediately cracked? I suppose I did okay with this because one hacker (who prefers not to be named) caught me literally on my way out of the conference for the last time. He had snagged the hashes earlier in the weekend and worked feverishly to crack the code. More details on the process are available after the jump.

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The ChipWhisperer At Defcon

We’ve seen [Colin]’s entry to The Hackaday Prize before. After seeing his lightning talk at Defcon, we had to get an interview with him going over the intricacies of this very impressive piece of hardware.

The ChipWhisperer is a security and research platform for embedded devices that exploits the fact that all security measures must run on real hardware. If you glitch a clock when a microcontroller is processing an instruction, there’s a good probability something will go wrong. If you’re very good at what you do, you can simply route around the code that makes up the important bits of a security system. Power analysis is another trick up the ChipWhisperer’s sleeve, analyzing the power consumption of a microcontroller when it’s running a bit of code to glean a little information on the keys required to access the system. It’s black magic and dark arts, but it does work, and it’s a real threat to embedded security that hasn’t had an open source toolset before now.

Before our interview, [Colin] did a few short and sweet demos of the ChipWhisperer. They were extraordinarily simple demos; glitching the clock when a microcontroller was iterating through nested loops resulted in what can only be described as ‘counter weirdness’. More advanced applications of the ChipWhisperer can supposedly break perfectly implemented security, something we’re sure [Colin] is saving for a followup video.

You can check out [Colin]’s 2-minute video for his Hackaday Prize entry below.

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