Tech Tips & Tricks

Fritz-Box VPN with strongswan and DS-Lite

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Setting up a working ipsec configuration for the fritz-box seems to be rather painful. I couldn’t make the default wizard variants work since they seem to use aggressive mode with psk and I was getting errors such as: found 1 matching config, but none allows pre-shared key authentication using Aggressive Mode It took me a while, so here are some working results from me. Hopefully your journey becomes easier then :) Read More...

HC-12 Hacking

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I have a strange obsession with the STM8 microcontroller. Arguably because it’s so cheap (you could get in in bulk from <0,40€ per piece or for 0,60€ on a dev-board), but powerful and versatile at the same time, due to: lots of GPIOs UART/SPI/I2C/ADC low power proper interrupts works both at 3.3V and 5V When investigating radio communication for some hobby projects a few years I stumbled upon the HC-12 module which easily adds wireless serial communication to your project. Read More...

Low-cost attacks on STM8 readout protection

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As part of my HC-12 hacking project I needed to acquire the firmware of an STM8 microcontroller that had readout protection enabled. I was long-time intrigued by fault-injection attacks, most recently triggered by this 35C3 Talk on PS2 Vita Hacking which used voltage glitching to overcome protection measures. From the STM8 reference manual: 4.5.1: Readout protection Readout protection is selected by programming the ROP option byte to 0xAA. When readout protection is enabled, reading or modifying the Flash program memory and DATA area [using the SWIM debug interface] is forbidden. Read More...