Buffer overflow into SROP Chain

`stage 1. Write "/bin/sh\x00" in the bss area`

`stage 2. execve("/bin/sh", NULL, NULL);`

`Get shell`

[Full exploit](https://github.com/wotmd/CTF_Exploit/tree/master/DEFCON_CTF_2019/speedrun001)

Original writeup (https://github.com/wotmd/CTF_Exploit/tree/master/DEFCON_CTF_2019/speedrun001).