This is a kernel challenge (with a little web one at first :) ) !

To build a local environment to solve the chalenge you can do ont of the following:

1. Download a docker image that is the same as a remote one (with one one small difference :) )

   docker run -d -p 3000:3000 myshelldocker/bsidesctf_2021_toilet_local
   

2. Build the environment from scratch with a Dockerfile from this repository. Run in privileged mode:

   git clone https://github.com/V3rochka/TOIlet_BSIDES_2021.git
   cd TOIlet_BSIDES_2021
   docker build -t bsidesctf_2021_toilet_local .
   docker run --privileged -d -p 3000:3000 bsidesctf_2021_toilet_local
   

The docker run will take time, you can run it in non-detached mode (-t) to see the init proccess

Solve the challenge on the local environment and use a final exploit on the remote server.

About the bug:

1. Achieve RCE in our webservice.
2. 4.19.173 kernel, please achieve root privs with this bug
   hint: /proc/kallsyms and /dev/kmsg is readable

Good luck!!