Internetwache CTF 2016: A numbers game (Code) Write-up

Description:

People either love or hate math. Do you love it? Prove it! You just need to solve a bunch of equations without a mistake.

Solution: 

	#!/usr/bin/python
	# Author: Kitwipat Towattana (@icheernoom)
	from pwn import *
	import sys
	r = remote('188.166.133.53', 11027)
	while True:
	try:
	result = r.recvline()
	log.success(result)
	problem = r.recvline()
	question = problem.split(': ')[1]
	log.info(problem)
	x, cond, num1, eq, num2 = question.split(' ')
	if "+" in cond:
	ans = int(num2) - int(num1)
	log.info("x = {0}".format(ans))
	r.send("{0}\r\n".format(ans))
	elif "-" in cond:
	ans = int(num2) + int(num1)
	log.info("x = {0}".format(ans))
	r.send("{0}\r\n".format(ans))
	elif "*" in cond:
	ans = int(num2) / int(num1)
	log.info("x = {0}".format(ans))
	r.send("{0}\r\n".format(ans))
	elif "/" in cond:
	ans = int(num2) * int(num1)
	log.info("x = {0}".format(ans))
	r.send("{0}\r\n".format(ans))
	except IndexError:
	log.success("{0}".format(problem))
	sys.exit()
	'''
	root@kali:~/Desktop# python code50.py
	[+] Opening connection to 188.166.133.53 on port 11027: Done
	[+] Hi, I heard that you're good in math. Prove it!
	[*] Level 1.: x + 10 = 23
	[*] x = 13
	[+] Yay, that's right!
	[*] Level 2.: x + 24 = 63
	[*] x = 39
	...[snip]...
	[*] Level 98.: x + 1259 = 1878
	[*] x = 619
	[+] Yay, that's right!
	[*] Level 99.: x * 1945 = 643795
	[*] x = 331
	[+] Yay, that's right!
	[*] Level 100.: x * 639 = 341865
	[*] x = 535
	[+] Yay, that's right!
	[+] IW{M4TH_1S_34SY}
	[*] Closed connection to 188.166.133.53 port 11027
	'''

view raw code50.py hosted with ❤ by GitHub

Flag: IW{M4TH_1S_34SY}