corCTF 2021 vmquack writeup: Writing a Custom Binary Ninja Architecture Plugin to Devirtualize a Crackme

This is a CTF challenge write-up for 'vmquack' (corCTF 2021) describing a custom x86_64-like CISC virtual machine implemented in assembly, its anti-debugging and virtualization techniques, the VM instruction set and operand encoding, a Binary Ninja plugin created to disassemble and lift the VM code, and the analysis steps used to derive the correct input that produces the flag.