###### We intercepted Sophia new defense system. It seems like she is using some kind of filter in the command sent to a certain server. There is also another security measure that we could not identify, we need a bypass.
TL;DR. This print contains the entire solve
![Solve](https://i.imgur.com/otv828j.jpg)
It was given to us the dockerfile and some Elixir/Erlang files. So instinctively we build the docker with```docker build .```
After we started our docker with```docker run image_id```
We can see the following message:
> Inserting 'Elixir.KillMe.Server', get_flag into blacklist
Then we connect to the docker, or the official server, with netcat or similar```nc ip 4000```
And ask for the key that was previously blacklisted```Elixir.KillMe.Server.get_flag```I don't know if it was the intended way but this print us the flag> CTF-BR{4f7er_7wEn7y_YE4r5_Erl4N9_57ill_D0_N07_H4VE_4_54nD80X}