ctf_aria

write up ctf by ariafatah

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Project maintained by ariafatah0711 Hosted on GitHub Pages — Theme by mattgraham

soal

Fix the syntax error in this Python script to print the flag.
Download Python script

hint

• Indentation is very meaningful in Python
• To view the file in the webshell, do: $ nano fixme1.py
• To exit nano, press Ctrl and x and follow the on-screen prompts.
• The str_xor function does not need to be reverse engineered for this challenge.

solve

wget https://artifacts.picoctf.net/c/26/fixme1.py

cat fixme1.py
###
import random

def str_xor(secret, key):
    #extend key to secret length
    new_key = key
    i = 0
    while len(new_key) < len(secret):
        new_key = new_key + key[i]
        i = (i + 1) % len(key)
    return "".join([chr(ord(secret_c) ^ ord(new_key_c)) for (secret_c,new_key_c) in zip(secret,new_key)])

flag_enc = chr(0x15) + chr(0x07) + chr(0x08) + chr(0x06) + chr(0x27) + chr(0x21) + chr(0x23) + chr(0x15) + chr(0x5a) + chr(0x07) + chr(0x00) + chr(0x46) + chr(0x0b) + chr(0x1a) + chr(0x5a) + chr(0x1d) + chr(0x1d) + chr(0x2a) + chr(0x06) + chr(0x1c) + chr(0x5a) + chr(0x5c) + chr(0x55) + chr(0x40) + chr(0x3a) + chr(0x5e) + chr(0x52) + chr(0x0c) + chr(0x01) + chr(0x42) + chr(0x57) + chr(0x59) + chr(0x0a) + chr(0x14)

flag = str_xor(flag_enc, 'enkidu')
  print('That is correct! Here\'s your flag: ' + flag)
'
###

python3 fixme1.py
#  File "/home/ariafatah/picoctf/s/f/fixme1.py", line 20
#     print('That is correct! Here\'s your flag: ' + flag)
# IndentationError: unexpected indent

## erorrnya karena inden yang terlalu maju
flag = str_xor(flag_enc, 'enkidu')
print('That is correct! Here\'s your flag: ' + flag)
'

python3 fixme1.py
# That is correct! Here's your flag: picoCTF{1nd3nt1ty_cr1515_09ee727a}

flag

picoCTF{1nd3nt1ty_cr1515_09ee727a}