Blazin’ Etudes – Hack A Sat 3 Quals (2022) – Writeup

(If you just want the solution, and not the story, skip down to “Emulating MLIL on z3”)

Introduction

This year was Samurai’s third time playing Hack A Sat’s (HAS) quals round. The first time we played, we qualified for finals. Year 2, we didn’t qualify. So this year we were hoping to qualify again. I personally wasn’t super involved in the first year, and only a bit involved last year (I don’t think the weekends lined up super great for me), but I was interested to take a shot at it this year and hopefully qualify!

Blazin’ Etudes was the third of a series of microblaze reversing challenges, released on the last day of the competition (Sunday). In order to properly appreciate it, we should briefly look at the preceding challenges.

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Reversing and exploiting a program running in an undocumented VM

DEF CON CTF 2021 Quals baby-a-fallen-lap-ray writeup

disassembled shellcode

Outline:

Introduction

This weekend, Samurai played the DEF CON CTF Qualifier event. We had a great time playing; much thanks to the organizers for putting on a great event! Many thanks to my teammates, it was awesome playing with you all!

One of the challenges this weekend was called baby-a-fallen-lap-ray. It was categorized as a pwn challenge, and it made a comment about being ‘the return of the parallel machine (or is it?)’.

Continue reading “Reversing and exploiting a program running in an undocumented VM”