PWN challenges are my favorite tasks at CTF contests. Such tasks effectively train you in real-life code analysis, while their write-ups usually describe all fine details, even those already addressed by other authors. Today, I will explain how to solve a task named “Useless Crap” by its author (it’s available on TG:HACK 2020). The author estimates its difficulty as hard. The task is very challenging indeed, and it took me almost twelve hours to complete it at the contest.