looking to get into fault injection for your reverse engineering projects, but don’t have the cash to set out for the necessary hardware? fear not, for the tools to glitch a chip may be as close as the nearest barbeque grill.
If you don’t understand what chip glitching is, perhaps a primer is in order. Glitching, more formally understood as electromagnetic fault injection (EMFI), or just fault injection, is a method that utilizes a pulse of electromagnetic energy to cause a fault in a running microcontroller or microprocessor. If the pulse occurs at just the right time, it may force the processor to avoid an instruction, leaving the system in a potentially exploitable state.
EMFI tools are commercially available — we even just recently featured a set to build your own — but [rqu]’s homebrew version is decidedly easier and cheaper than just about anything else. It consists of a piezoelectric gas grill igniter, a bit bit of enameled magnet wire, and half of a little toroidal ferrite core. The core fragment gets a few turns of wire, which then gets soldered to the terminals on the igniter. pressing the button produces a high-voltage pulse, which gets turned into an electromagnetic pulse by the coil. There’s a video of the tool in utilize in the Twitter thread, showing it easily glitching a pic running a simple loop program.
To be sure, a tool as simple as this won’t do the technique in every situation, but it’s a cheap method to begin checking out the prospective of fault injection.
Thanks to [Jonas] for the tip.
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