To many, the Enigma machine is an enigma. But it’s really quite simple. The following is a step-by-step explanation of how it works, from the basics to the full machine.
Possibly the greatest dedicated cipher machine in human history the Enigma machine is a typewriter-sized machine, with keyboard included, that the Germans used to encrypt and decrypt messages during World War II. It’s also one of the machines that the Polish Cipher Bureau and those at Britain’s Bletchley Park figured out how to decipher, or break. Most recently the story of how it was broken was the topic of the movie The Imitation Game.
Grab a shortwave radio, go up on your roof at night, turn on the radio, and if the ionosphere is just right, you’ll be able to tune into some very, very strange radio stations. Some of these stations are just a voice — usually a woman’s voice — simply counting. Some are Morse code. All of them are completely unintelligible unless you have a secret code book. These are number stations, or radio stations nobody knows much about, but everyone agrees they’re used to pass messages from intelligence agencies to spies in the field.
A few years ago, we took a look at number stations, their history, and the efforts of people who document and record these mysterious messages used for unknown purposes. These number stations exist for a particular reason: if you’re a spy, you would much rather get caught with an ordinary radio instead of a fancy encryption machine. Passing code through intermediaries or dead drops presents a liability. The solution to both these problems lies in broadcasting messages in code, allowing anyone to receive them. Only the spy who holds a code book — or in the case of the Cuban Five, software designed to decrypt messages from number stations — can decipher the code.
Number stations are a hack, of sorts, of the entire concept of broadcasting. For all but a few, these number stations broadcast complete gibberish. Only to the person holding the code book or the decryption software do these number stations mean anything. However, since the first number stations went on the air over one hundred years ago, broadcasting has changed dramatically. We now have the Internet, and although most web services cannot be considered a one-to-many distribution as how broadcasting is defined, Twitter can. Are there number stations on Twitter? There sure are. Are they used by spies or agents of governments around the world? That’s a little harder to say.
At this year’s BlackHat Asia security conference, researchers from Cylance disclosed two potentially fatal flaws in the UEFI firmware of Gigabyte BRIX small computers which allow a would-be attacker unfettered low-level access to the computer.
Gigabyte has been working on a fix since the start of 2017. Gigabyte are preparing to release firmware updates as a matter of urgency to only one of the affected models — GB-BSi7H-6500 (firmware vF6), while leaving the — GB-BXi7-5775 (firmware vF2) unpatched as it has reached it’s end of life. We understand that support can’t last forever, but if you sell products with such a big fault from the factory, it might be worth it to fix the problem and keep your reputation.
The two vulnerabilities that have been discovered seem like a massive oversight from Gigabyte, They didn’t enable write protection for their UEFI (CVE-2017-3197), and seem to have thrown cryptography out of the window when it comes to signing their UEFI files (CVE-2017-3198). The latter vulnerability is partly due to not verifying a checksum or using HTTPS in the firmware update process, instead using its insecure sibling HTTP. CERT has issued an official vulnerability note (VU#507496) for both flaws.
Attackers may exploit the vulnerabilities to execute unsigned code in System Management Mode (SMM), planting whatever malware they like into the low level workings of the computer. Cylance explain a possible scenario as follows:
The attacker gains user-mode execution through an application vulnerability such as a browser exploit or a malicious Word document with an embedded script. From there, the attacker elevates his privileges by exploiting the kernel or a kernel module such as Capcom.sys to execute code in ring 0. A vulnerable SMI handler allows the attacker to execute code in SMM mode (ring -2) where he finally can bypass any write protection mechanisms and install a backdoor into the system’s firmware.
With all this said, it does raise some interesting opportunities for the hacker community. We wonder if anyone will come up with a custom UEFI for the Brix since Gigabyte left the keys in the door.
World War I began in 1914 as a fight among several European nations, while the United States pursued a policy of non-intervention. In fact, Woodrow Wilson was reelected President largely because “He kept us out of war”. But as the war unfolded in Europe, an intercepted telegram sent by the German Foreign Secretary, Arthur Zimmermann, to the Mexican government inflamed the U.S. public opinion and was one of the main reasons for the entry of the U.S. into WWI. This is the story of the encrypted telegram that changed the last century.
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.
Our jaw dropped repeatedly during this presentation. Go watch it now.
Although I’ve been to several DEF CONs over the past few years, I’ve never found time to devote to solving the badge. The legendary status of all the puzzles within are somewhat daunting to me. Likewise, I haven’t yet given DefCon DarkNet a try either — a real shame as the solder-your-own-badge nature of that challenge is right up my alley.
But finally, at the Hackaday SuperCon I finally got my feet wet with the crypto challenge created by [Voja Antonic]. He developed a secondary firmware which anyone could easily flash to their conference badge (it enumerates as a USB thumb drive so just copy it over). This turned it into a five-puzzle challenge meant to take two days to solve, and it worked perfectly.
Thar’ be spoilers below. I won’t explicitly spill the answers, but I will be discussing how each puzzle is presented and the different methods people were using to finish the quest. Choose now if you want to continue or wait until you’ve solved the challenge on your own.
If you’ve spent any time around prime numbers, you know they’re a pretty odd bunch. (Get it?) But it turns out that they’re even stranger than we knew — until recently. According to this very readable writeup of brand-new research by [Kannan Soundararajan] and [Robert Lemkein], the final digits of prime numbers repel each other.
More straightforwardly stated, if you pick any given prime number, the last digit of the next-largest prime number is disproportionately unlikely to match the final digit of your prime. Even stranger, they seem to have preferences. For instance, if your prime ends in 3, it’s more likely that the next prime will end in 9 than in 1 or 7. Whoah!
Even spookier? The finding holds up in many different bases. It was actually first noticed in base-three. The original paper is up on Arxiv, so go check it out.
This is a brand-new finding that’s been hiding under people’s noses essentially forever. The going assumption was that primes were distributed essentially randomly, and now we have empirical evidence that it’s not true. What this means for cryptology or mathematics? Nobody knows, yet. Anyone up for wild speculation? That’s what the comments section is for.
(Headline photo of researchers Kannan Soundararajan and Robert Lemke: Waheeda Khalfan)