Connect CW to a foreign device

Embedded Security Glitching
#1

Hello together,

I performed a couple of glitching attacks on the STM32. Now I like to test the ChipWhisperer with a non
dedicated device and connect a foreign device to the CW. Especially I thought about connecting a NXP Eval board to CW Pro and see if it is glitchable. I already connect:

  • GND / Vss
  • Vcc
  • Clock
    to the CW connector.
    My questions are, how do i perform the crowbar glitch with such a device? Which pins have to be connected and what have the CW settings have to look like?
    Unfortunatly I havent found this in the Wiki, but it would be really interesstng tu evaluate such a real-world scenario.

Thanks
Lukas

#2

Hi Lukas,

Our tutorial on glitching the LPC1114 bootloader sounds right up your alley :slight_smile:

In addition to what you’ve already done, you’ll need to connect the trigger pin. It would also be a good idea to remove any decoupling capacitors for the target microcontroller and to put a shunt resistor between the board power supply and the target supply pins. All these things are done in the above tutorial.

Alex

#3

Hi Alex,

thanks for the quick response! The tutorial helps, but I’ve still some questions left.
The Final result would be that the SMA supllies the core voltage of the chip with 3.3V interrupted by short glitches aka. voltage glitching :smiley:
For some reason my setup is not supplying 3.3V over the SMA.
I understood that pin 8 is the input voltage which should be the normal supply voltage of the target.
Pin4 is my clock signal from the device. (clock frequency is correctly measured by CW)
Pin2 is GND and connected to the target.

How do get 3.3V over the SMA like on the sample board with my custom setup?

Thanks
Lukas

#4

The SMA is an open drain setup, which means it cannot supply voltage, it can only pull it low. You need to hook the 3.3V supply from the ChipWhisperer 20-pin connector (pin 3) up to your board. I’d just ignore pin 8, as it’s not needed if you’re communicating at 3.3V.

Alex