This will be a short but sweet writeup. You can find a backup of the challenge here on my GitHub in case you don’t have access to it.
The challenge is simply to extract some data from a PDF file.
When you open the PDF you are presented with this:
Knowing this, it looked like there is just an image or drawing over what we want to see, so I did some research to find a suitable program to disassemble the PDF.
I stumbled upon mutools which I installed in Kali:
pt install mupdf-tools
While the tutorial I was following had some complicated steps to get what I was looking for, I simply gave
mutool extract cybercorp_memo.pdf
This gave me the following image:
And the follwing flag:
MetaCTF{politics_are_for_puppets}
And that’s it! Just knowing the right tool for the job makes it pretty easy.