Confidential

We got our hands on a confidential case file from some self-declared "black hat hackers"... it looks like they have a secret invite code.

Overview

we have a pdf file contain our flag on a hidden qr code

i will transfer it to my machine for easier work

my machine

nc -vlnp 1234 > Repdf.pdf

target machine

nc 10.9.43.204 1234 < Repdf.pdf

i will use binwalk for searching binary images

binwalk Repdf.pdf

hmm, nothing usefull

so, we can try with pdfimages

pdfimages -all Repdf.pdf imgs

finally, we extracted main file to 3 component files

here you go

Flag	root.txt
Answer	flag{e08e6ce2f077a1b420cfd4a5d1a57a8d}