0x00 Overview Last weekend we participated Defcon CTF 2020 Qualifier and got 9th place finally, my teammates tql. With some help from my teammates, I solved 2 challenges, cursed and blursed. These 2 challenges are quite interesting, so here is my write-up for it. :) The binary file for these 2 challenges are exactly identical. In the binary, a blake2b proof of work is required first. Then clone function is called to initiate a new thread. In new thread, flag is read into stack, and bozo.bin is m...