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2025-01-17

38c3 - illegal instructions

I attended my first CCC (Chaos Computer Congress) in Hamburg. I came for the talks and stayed for all the rabbit holes I fell into.

Some data:

Content

Talks

FNord Jahresrueckblick

It was nice to see fefe in rl with the famous FNord Jahresruecklick about security related news in the year 2024.

io_uring, eBPF, XDP and AF_XDP

Talk gave an overview over the io_uring concept such as XDP and its opportunity.

io_uring allows to give the kernel some userspace buffer for IO operations obsoleting all the read/write calls. XDP (short for eXpress Data Path) bypasses the whole linux network stack an enables custom packet handling, as seen in the famous XDP diagram.

Ten Years of Rowhammer: A Retrospect (and Path to the Future)

The people around rowhammer summarized the attack itself such as further papers and scenarios that came up since its first release 10 years ago in this talk. They also stated, that all the studies together share a low amount of real systems where the attacks has been proven to work successfully. In order to gain more real world data and to underline that rowhammer is a real world threat, they asked for participation using their custom os. The os contain the attacks itself such as some reverse engineering stuff to parameterize the attacks based on the given hardware.

Oh, and they also provided some live USB sticks as goddie containing the os image. Nice try!1

Attack Mining: How to use distributed sensors to identify and take down adversaries

This was a journey from analyzing bad login attempts in the auth.log over identifying a bot net finishing in contacting the ISP’s of the compromised server. I like how the talk starts quite naive with some curiosity about the login attempts and goes deeper into the rabbit hole step by step.

Further recommendations

Sidequests

DECT

Sidequest of day one was to get my dect phone working. Well in the end my Doro Comfort 1010 wasn’t supported and my other FritzFon didn’t boot…

Simcards to the rescue! I got one for my dual-sim mobile phone and registered my extension 25010.

Soldering

There was a soldering area with fully equipped work places and a donation-based supply for some kits.

LED Animals

The axolothle was a good first soldering project to get back into the game. The cat was my very first smd project, and it went quite well \o/

Kippenautomat

One of my favorite things at the congress was the Kippenautomat where one can get electronics for five bucks. Especially the “random electronic circuit” got my attention.

My first random circuit kippenschachtel was a spinner with blinking LED’s on it

ArduTouch Music Synthesizer

At the assembly hall, I stumbled across several (actually 9) synthesizers looking the same but sounding different2. Mitch told me that he developed the whole synth himself in the last eight yrs. There are also not nine different circuits but only one that can be programmed in several ways enabled by the underlying ATmega32 chip.

It’s called ArduTouch Music Synthesizer.

Keyboard meetup

It was fun peering with all those people which also fell into the rabbit hole and even created their own board.

The “Tr9shpad” got my attention, which is a 18-key keyboard with two rotary encoders and a display. It’s key mapping allows T9-style tap-dancing and it “should be helt like a gameboy”. I also got one PCB to build my own one! \o/

Neurodivergent meetup

This was the very first appointment I attended to at the conference. The focus was on stimming. This was an eye opener for me, as I stim’ all the time but didn’t know there is a topic that articulates this behavior pretty well. Or as wikipedia describes it:

Stimming has been interpreted as a protective response to overstimulation, in which people calm themselves by blocking less predictable environmental stimuli, to which they have a heightened sensitivity.

Another topic related to stimming was masking/camouflaging: hiding neurodivergency by trying to mimic neurotypical behavior. I often notice this myself of trying to avoid stimming or have a guilty concense about doing it3.

There were also all kinds of fidget toys that were passed around, reminding me of my other blog article about thinking toys.

TinyGS workshop

I attended the Build Your Own Satellite Ground Station workshop using a self-bent antenna, Lilygohttps://lilygo.cc/products/t3-tcxo such as TinyGS.

Some data:

My ground station is now collecting some cool data from space low earth orbit.

Some impressions

  1. Don’t just use USB sticks handed out by some untrusted thirds. To their defense, that’s what they also said in the end.
  2. The bass with the super saw is my favorite which turns out to be the default \o/
  3. Well, no guilt from now on as I’m more aware \o/