Interstellar
In this challenge, we have access to a network communication saved in a pcap file.
We have just ICMP requests. At first I was thinking about some kind of ping pong challenge but it was not. But when we look at the ICMP packet sent, we can see some interesting stuff.
As we can see in the first and last request, we have the PNG header and its trailer that we know because it’s explained on this website.
So I created a program that will extract every request and extract the hexadecimal of the image. Unfortunately, I couldn’t manage to recreate the image directly in the python code. But this website allows us to do it.
We then download the image and we get the flag:
