dealbreaker's comments

dealbreaker | 1 year ago | on: Zero Day in Microchip SAM Microcontrollers

Particularly for this adventure, I have kept it strictly private. It was a hobby project and also was a challenge to myself.

In the process I learned not only of M32C(backwards compatible with M16C processor module in Ghidra), but as I mentioned, certain compiler bugs(not following the ISA spec strictly) that it is more flexible despite what the M16/M32C software manual says. However this meant that emulation produced wrong results, and thus my patches to fix it and ultimate success

I have opened a Ghidra support ticket, but I needed to provide proof that there is ISA behavior not described in the software manuals.

dealbreaker | 1 year ago | on: Zero Day in Microchip SAM Microcontrollers

How did reverse engineering m16c prove challenging? I recently extracted a 4 stage encrypted payload from an M16C arch that also used time-based encryption. Each time it was run, the output was different. The time based key was also rotating.

It used a very simple custom encryption for the time stuff and AES in ECB mode.

Protip Ghidra does not emulate inherent CPU behavior of INDEX instructions, behaviour not specified in ISA. I had to backport M32C instructions and patch M16C slaspec to emulate this behavior, caused by compiler bugs.

dealbreaker | 1 year ago | on: Blue field entoptic phenomenon

About 10 years ago I went to an ophthalmologist. I had experienced a situation which I can only describe as a visual phenomenon traveling from one part of my visual field to beneath it. I was partially blind because of it. I can only think it was a very small stroke or something. They found nothing wrong with my eyes and in passing I mentioned these white things.

Combined with my inability to explain what I saw, the doctor was visibly annoyed and said I need a psychiatrist not an ophthalmologist.

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