digipad.py

# coding: utf8

from pwn import *

'''
~ » nc 46.30.204.44 4000
             ,---,---,---,
             | 1 | 2 | 3 |
             '---,---,---'
             | 4 |   |   |
             '---,---,---'
             | 7 | 8 |   |
             '---,---,---'
             | * |   | # |
             '---'---'---'
Better be fast, you have 2 seconds.
Enter the 4 digit code : 

'''

def search_used_digits(pad):
	digit = []

	for i in range(10):
		if not str(i) in pad:
			digit.append(i)

	return digit

found = False
while found == False:
	r = remote('46.30.204.44', 4000)

	pad = r.recvuntil("Better ")
	r.recvuntil("Enter the 4 digit code :")

	# print pad
	used_digits = search_used_digits(pad)


	if len(used_digits) == 4:
		r.sendline("".join([str(i) for i in used_digits]))
		result = r.recvuntil("\n")

		if not "Wrong" in result:
			found = True
			print result
			r.interactive()

	r.close()

What is the argument pad?

This is the digipad string scheme like this example:

             ,---,---,---,
             | 1 | 2 | 3 |
             '---,---,---'
             | 4 |   |   |
             '---,---,---'
             | 7 | 8 |   |
             '---,---,---'
             | * |   | # |
             '---'---'---'