In `CSAW Quals 2018 - shell_code` challenge, there is a simple `stack overflow` vulnerability that leads to code injection and eventually, execution of `/bin/sh`. The interesting part is that you cannot provide the whole shell code in one place; however, you need to break your shell code into 3 parts, feed each part to the program in a different place, and connect these 3 parts using jumps.

Original writeup (https://github.com/sajjadium/ctf-writeups/tree/master/CSAWQuals/2018/shell_code).