[https://infosec.rm-it.de/2019/04/15/wpictf-2019-linux-category/#4](https://infosec.rm-it.de/2019/04/15/wpictf-2019-linux-category/#4)

Original writeup (https://infosec.rm-it.de/2019/04/15/wpictf-2019-linux-category/#4).