0x00 Overview Although I failed to solve the challenge during CTF, but I think it is worthwhile to do a write-up. The challenge is to exploit a PHP script engine using this bug. We can execute arbitrary PHP code but we must bypass disabled_function restriction to execute shell command, using a UAF vulnerability. Therefore, this is actually more a Pwn challenge than a Web challenge. However, different from official PHP engine, a custom libphp7.so is provided. This engine does not provide any loop...