Useless Crap? No, not nearly! Advance your binary exploitation skills by solving a sophisticated CTF challenge

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.
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