33C3: Works For Me

December 30, 2016 by Elliot Williams 20 Comments

The Chaos Communication Congress (CCC) is the largest German hacker convention by a wide margin, and it’s now in its thirty-third year, hence 33C3. The Congress is a techno-utopian-anarchist-rave with a social conscience and a strong underpinning of straight-up hacking. In short, there’s something for everyone, and that’s partly because a CCC is like a hacker Rorschach test: everyone brings what they want to the CCC, figuratively and literally. Somehow the contributions of 12,000 people all hang together, more or less. The first “C” does stand for chaos, after all.

What brings these disparate types to Hamburg are the intersections in the Venn diagrams. Social activists who may actually be subject to state surveillance are just as interested in secure messaging as the paranoid security geek or the hardcore crypto nerd who’s just in it for the algorithms. Technology, and how we use it to communicate and organize society, is a pretty broad topic. Blinking lights also seem to be in the intersection. But on top of that, we are all geeks. There’s a lot of skill, smarts, and know-how here, and geeks like sharing, teaching, and showing off their crazy creations.

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33C3: If You Can’t Trust Your Computer, Who Can You Trust?

December 29, 2016 by Elliot Williams 47 Comments

It’s a sign of the times: the first day of the 33rd Chaos Communications Congress (33C3) included two talks related to assuring that your own computer wasn’t being turned against you. The two talks are respectively practical and idealistic, realizable today and a work that’s still in the idea stage.

In the first talk, [Trammell Hudson] presented his Heads open-source firmware bootloader and minimal Linux for laptops and servers. The name is a gag: the Tails Linux distribution lets you operate without leaving any trace, while Heads lets you run a system that you can be reasonably sure is secure.

It uses coreboot, kexec, and QubesOS, cutting off BIOS-based hacking tools at the root. If you’re worried about sketchy BIOS rootkits, this is a solution. (And if you think that this is paranoia, you haven’t been following the news in the last few years, and probably need to watch this talk.) [Trammell]’s Heads distribution is a collection of the best tools currently available, and it’s something you can do now, although it’s not going to be easy.

Carrying out the ideas fleshed out in the second talk is even harder — in fact, impossible at the moment. But that’s not to say that it’s not a neat idea. [Jaseg] starts out with the premise that the CPU itself is not to be trusted. Again, this is sadly not so far-fetched these days. Non-open blobs of firmware abound, and if you’re really concerned with the privacy of your communications, you don’t want the CPU (or Intel’s management engine) to get its hands on your plaintext.

[Jaseg]’s solution is to interpose a device, probably made with a reasonably powerful FPGA and running open-source, inspectable code, between the CPU and the screen and keyboard. For critical text, like e-mail for example, the CPU will deal only in ciphertext. The FPGA, via graphics cues, will know which region of the screen is to be decrypted, and will send the plaintext out to the screen directly. Unless someone’s physically between the FPGA and your screen or keyboard, this should be unsniffable.

As with all early-stage ideas, the devil will be in the details here. It’s not yet worked out how to know when the keyboard needs to be encoded before passing the keystrokes on to the CPU, for instance. But the idea is very interesting, and places the trust boundary about as close to the user as possible, at input and output.

33C3: Understanding Mobile Messaging And Its Security

December 28, 2016 by Elliot Williams 17 Comments

If you had to explain why you use one mobile messaging service over another to your grandmother, would you be able to? Does she even care about forward secrecy or the difference between a private and public key is? Maybe she would if she understood the issues in relation to “normal” human experiences: holding secret discussions behind closed doors and sending letters wrapped in envelopes.

Or maybe your grandmother is the type who’d like to completely re-implement the messaging service herself, open source and verifiably secure. Whichever grandma you’ve got, she should watch [Roland Schilling] and [Frieder Steinmetz]’s talk where they give both a great introduction into what you might want out of a secure messaging system, and then review what they found while tearing apart Threema, a mobile messaging service that’s popular in Germany. Check out the slides (PDF). And if that’s not enough, they provided the code to back it up: an open workalike of the messaging service itself.

This talk makes a great introduction, by counterexample, to the way that other messaging applications work. The messaging service is always in the middle of a discussion, and whether they’re collecting metadata about you and your conversations to use for their own marketing purposes (“Hiya, Whatsapp!”) or not, it’s good to see how a counterexample could function.

The best quote from the talk? “Cryptography is rarely, if ever, the solution to a security problem. Cryptography is a translation mechanism, usually converting a communications security problem into a key management problem.” Any channel can be made secure if all parties have enough key material. The implementation details of getting those keys around, making sure that the right people have the right keys, and so on, are the details in which the devil lives. But these details matter, and as mobile messaging is a part of everyday life, it’s important that the workings are transparently presented to the users. This talk does a great job on the demystification front.

33C3: Breaking IoT Locks

December 28, 2016 by Elliot Williams 16 Comments

Fast-forward to the end of the talk, and you’ll hear someone in the audience ask [Ray] “Are there any Bluetooth locks that you can recommend?” and he gets to answer “nope, not really.” (If this counts as a spoiler for a talk about the security of three IoT locks at a hacker conference, you need to get out more.)

Unlocking a padlock with your cellphone isn’t as crazy as it sounds. The promise of Internet-enabled locks is that they can allow people one-time use or limited access to physical spaces, as easily as sending them an e-mail. Unfortunately, it also opens up additional attack surfaces. Lock making goes from being a skill that involves clever mechanical design and metallurgy, to encryption and secure protocols.

In this fun talk, [Ray] looks at three “IoT” locks. One, he throws out on mechanical grounds once he’s gotten it open — it’s a $100 lock that’s as easily shimmable as that $4 padlock on your gym locker. The other, a Master lock, has a new version of a 2012 vulnerability that [Ray] pointed out to Master: if you move a magnet around the outside the lock, it actuates the motor within, unlocking it. The third, made by Kickstarter company Noke, was at least physically secure, but fell prey to an insecure key exchange protocol.

Along the way, you’ll get some advice on how to quickly and easily audit your own IoT devices. That’s worth the price of admission even if you like your keys made out of metal instead of bits. And one of the more refreshing points, given the hype of some IoT security talks these days, was the nuanced approach that [Ray] took toward what counts as a security problem because it’s exploitable by someone else, rather than vectors that are only “exploitable” by the device’s owner. We like to think of those as customization options.

SKiDL: Script Your Circuits In Python

December 28, 2016 by Elliot Williams 28 Comments

SKiDL is very, very cool. It’s a bit of Python code that outputs a circuit netlist for KiCAD.

Why is this cool? If you design a PCB in KiCAD, you go through three steps: draw the schematic, assign footprints to the symbolic parts, and then place them. The netlist ties all of these phases together: it’s a list of which parts are connected to which, the output of schematic capture and the input for layout. The ability to generate this programmatically should be useful.

For instance, you could write a filter circuit generator that would take the order, cutoff, and type of filter as inputs, and give you a spec’ed netlist as output. Bam! In your next design, when you need a different filter, you just change a couple of variables. Writing your circuits as code would make arranging the little sub-circuits modular and flexible, like functions in code.

At the very least, it’s an interesting alternative to the mouse, click, drag, click paradigm that currently dominates the schematic capture phase. Just as some of you like OpenSCAD for 3D modelling, some of you will like SKiDL for circuit design.

We’ve become so accustomed to the circuit diagram as the means of thinking about circuits that we’re not sure that we can ever give up the visual representation entirely. Maybe designing with SKiDL will be like sketching out block diagrams, where each block is a bit of Python code that generates a circuit module? Who knows? All we know is that it sounds potentially interesting, and that it’ll certainly be mind-expanding to give it a try.

Give it a shot and leave feedback down in the comments!

Ken Shirriff Takes Us Inside The IC, For Fun

December 27, 2016 by Elliot Williams 13 Comments

[Ken Shirriff] has seen the insides of more integrated circuits than most people have seen bellybuttons. (This is an exaggeration.) But the point is, where we see a crazy jumble of circuitry, [Ken] sees a riddle to be solved, and he’s got a method that guides him through the madness.

In his talk at the 2016 Hackaday SuperConference, [Ken] stepped the audience through a number of famous chips, showing how he approaches them and how you could do the same if you wanted to, or needed to. Reading an IC from a photo is not for the faint of heart, but with a little perseverance, it can give you the keys to the kingdom. We’re stoked that [Ken] shared his methods with us, and gave us some deeper insight into a handful of classic silicon, from the Z80 processor to the 555 timer and LM7805 voltage regulator, and beyond.

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33C3: Chris Gerlinsky Cracks Pay TV

December 27, 2016 by Elliot Williams 40 Comments

People who have incredible competence in a wide range of fields are rare, and it can appear deceptively simple when they present their work. [Chris Gerlinksy]’s talk on breaking the encryption used on satellite and cable pay TV set-top boxes was like that. (Download the slides, as PDF.) The end result of his work is that he gets to watch anything on pay TV, but getting to watch free wrestling matches is hardly the point of an epic hack like this.

The talk spans hardware reverse engineering of the set-top box itself, chip decapping, visual ROM recovery, software reverse analysis, chip glitching, creation of custom glitching hardware, several levels of crypto, and a lot of very educated guessing. Along the way, you’ll learn everything there is to know about how broadcast streams are encrypted and delivered. Watch this talk now.

Some of the coolest bits:

Reading out the masked ROM from looking at it with a microscope never fails to amaze us.
A custom chip-glitcher rig was built, and is shown in a few iterations, finally ending up in a “fancy” project box. But it’s the kind of thing you could build at home: a microcontroller controlling a switch on a breadboard.
The encoder chip stores its memory in RAM: [Chris] uses a beautiful home-brew method of desoldering the power pins, connecting them up to a battery, and desoldering the chip from the board for further analysis.
The chip runs entirely in RAM, forcing [Chris] to re-glitch the chip and insert his payload code every time it resets. And it resets a lot, because the designers added reset vectors between the bytes of the desired keys. Very sneaky.
All of this was done by sacrificing only one truckload of set-top boxes.