Category Archives: CTF

English [EasyCTF 2018] [Reverse 150 – Soupstitution Cipher] Write Up


For this challenge, we need to reverse a briefly obfuscated python script to find an input value that will validate some conditions to get the flag.

#!/usr/bin/env python3

from binascii import unhexlify as sOup
from operator import attrgetter as souP

ME_FLAGE = 'censored'

SoUp = input
soUP = hex
sOUp = print
sOuP = ord
SOuP = open

def SoUP(sOUP):
 soup = 0
 while sOUP != 0:
  soup = (soup * 10) + (sOUP % 10)
  sOUP //= 10
 return soup

def SOup(sOUP):
 soup = 0
 for soUp in sOUP:
  soup *= 10
  soup += sOuP(soUp) - sOuP('0')
 return soup

def SOUP():
 Soup = SoUp()[:7]
 if not souP('isdigit')(Soup)():
  sOUp("that's not a number lol")

 soup = SoUP(SOup(Soup))
 SouP = souP('zfill')(soUP(soup)[2:])(8)[-8:]
 if sOup(SouP) == souP('encode')('s0up')():
  sOUp("oh yay it's a flag!", ME_FLAGE)
  sOUp('oh noes rip u')

if __name__ == '__main__':


Continue reading [EasyCTF 2018] [Reverse 150 – Soupstitution Cipher] Write Up


Hello everyone,

Last year, we were on final for the Defcamp. We finished in the bottom of the ranking (thanks to… actually to the night before, which had been a bit rude ^^).
But this year, we decided to be better (even if we again tried a lot of bars). And it paid! We were constantly moving from place #5 to #6, and ten minutes before the end, one of us flagged a challenge, and secured the 5th place!

Even if it’s not the first time we get into the Top5, we were in front of famous teams, and it was a real challenge to deal with it. But, hey, fighting DCUA, P4, and others was really fun after all! πŸ™‚

We would like to thanks the organizers of the CTF, and of the Defcamp for their awesome work, and to say them : “See you next year ;)”

Here are the ranks :

defcamp ranking

English [NDH 2017] Back On The Event

Hello buddies,

From Saturday 24th 10AM to Sunday 25th 7AM, there was the most known french conference: Nuit Du Hack. As every Β year, it was an awesome conference, with a lot of conferences, friends, workshops, and beers πŸ™‚

But, it’s not only conferences, it’s also challenges! And, here, at 0x90r00t, we love challenges (I bet you already knew it πŸ™‚ )!
So, we did the public CTF and finished 7th, which is not bad!

This year, Wavestone also organized a mini CTF during the day, just for fun (and actually, it was really fun), and we finished 3rd!

Oh… But wait… I almost forgot! There was a spying challenge, and… oh… actually, we finished first! πŸ˜‰

You’ll find some write ups below:

  • Spying challenge part 1 (FR only)
  • Spying challenge part 2 (FR only)
  • Spying challenge part 3 (FR only)
  • More soon

And here is the ranking (thanks to P_TE for the picture)!