CUCTF 2020 Dr. Xorisaurus Heap Writeup (glibc 2.32 UAF)

This writeup describes a CTF challenge exploit against glibc 2.32 heap protections, explaining how safe-linking obfuscation, scanf-induced large allocations, malloc_consolidate behavior, and an 8-byte UAF are abused to perform tcache poisoning and ultimately overwrite __free_hook to achieve a shell. The author details the challenge features, the leak technique using largebin consolidation, pointer deobfuscation math, and how the final payload changes __free_hook to system; it is an educational exploit walkthrough rather than a report of active malicious activity.