Wizard
You have stumbled upon a wizard on your path to the flag. You must answer his questions!
PS (not challenge related), thank you so much to Hadrian for supporting NahamCon 2022!
Press the Start button on the top-right to begin this challenge.
Solving
To solve this challenge, you need to connect to your own instance via netcat. Then you will be asked for some specific calculations. Such as binary to ascii.
We solved this with this quick & dirty solve.py script.
#!/usr/share/env python
from pwn import *
import binascii
import base64
import struct
import time
host,port = 'challenge.nahamcon.com', 31997
p = log.progress('Working')
try:
s = remote(host, port)
p.status('First question - binary to ascii...')
s.recvuntil(b'binary string?')
binary_string=s.recv().split()
binary_string=binary_string[0].decode('utf-8')
hex_s=hex(int(binary_string,2))
ascii_text=bytes.fromhex(hex_s[2:]).decode("utf-8")
s.sendline(bytes(ascii_text,'latin1'))
time.sleep(1)
p.status('First question - done!')
time.sleep(1)
p.status('Second question - hex to ascii...')
time.sleep(1)
s.recvuntil(b'hex string?')
string=s.recv().split()
string=string[0].decode('utf-8')
ascii_text=bytes.fromhex(string).decode('utf-8')
s.sendline(bytes(ascii_text,'latin1'))
p.status('Second question - done!')
time.sleep(1)
p.status('Third question - octal to ascii')
time.sleep(1)
s.recvuntil(b'octal string?')
string=s.recv().split()
string=string[8].decode('utf-8')
string=hex(int(string,8))
ascii_text=bytes.fromhex(string[2:]).decode('utf-8')
s.sendline(bytes(ascii_text,'latin1'))
p.status('Third question - done!')
time.sleep(1)
p.status('Fourth question - int to ascii')
time.sleep(1)
s.recvuntil(b'this integer?')
string=s.recv().split()
string=string[6].decode('utf-8')
string=hex(int(string))
ascii_text=bytes.fromhex(string[2:]).decode('utf-8')
s.sendline(bytes(ascii_text,'latin1'))
p.status('Fourth question - done!')
time.sleep(1)
p.status('Fifth question - decoding base64 string...')
time.sleep(1)
s.recvuntil(b'Base64 string?')
string=s.recv().split()
string=string[0].decode('utf-8')
ascii_text=base64.b64decode(string)
s.sendline(ascii_text)
p.status('Fifth questions - done!')
time.sleep(1)
p.status('Sixth questions - converting little to big endian and calculate ascii text...')
time.sleep(1)
s.recvuntil(b'hex string?')
string=s.recv().split()
string=string[0].decode('utf-8')
string=binascii.unhexlify(string)
ascii_text=string[::-1]
s.sendline(ascii_text)
p.status('Sixth questions - done!')
time.sleep(1)
p.status('Getting flag...')
time.sleep(1)
s.recvuntil(b'witts: ')
string=s.recvuntil(b"}").decode('utf-8')
p.success('Got the flag for you!')
time.sleep(1)
except:
print('Could not connect to target... something went wrong. Sorry!')
print("\n\n\t"+string+"\n\n")