# Eat Sleep Smash Repeat

I'm the author of this challenge. This is my thoughts on how to solve the challenge.

![alt text](1.png "Chall")

A captcha and a submit field.

Let's submit the captcha: `6\0wg`.

![alt text](2.png "Chall")

Maybe it was a `v` instead of `w`. After each fail the challenger understands something is wrong. If you notice clearly there is a nullbyte in the string...

What this challenge simulates is a shitty C library ported to PHP.

Submitting just the first number we move on to the next level:

![alt text](3.png "Chall")

After reaching level 5 we are presented with this screen:

![alt text](4.png "Chall")

Clicking flag retrieval we get a screen saying we should practice more.. What?

![alt text](5.png "Chall")

Obviously something is up.

Let's try again, solving the first 5 levels but this time we click flag retrieval faster.

![alt text](6.png "Chall")

Notice how the title of the page changed from "Rookie" to "Worthy challenger".

What's new is the time limit...

Time to fire up Python and automate this.

![alt text](7.png "Chall")

import requests
import thread
from PIL import Image
from io import BytesIO
import hashlib
import time
import psutil

s = requests.Session()


mapping = []
'cd1992f946b28a968f4f814468607536': '1',
'8fd08858070091aaacd6afc9c6df909f': '2',
'66ee914964c0211046fd48ed245d40ba': '3',
'6fe7a1bd69cde572ce1d1b9f04f78677': '4',
'572a28f5bcb1f269d85e2934fce189df': '5',
'd0c5dc424d4aecd08975c538e19a2fc2': '6',
'06aafe9d840414ad573dd78680d1b041': '7',
'43d88075ac9b4e16e074be315e501187': '8',
'82aafc241c1f1be0ae61e3cfb46e209e': '9',

def get_captcha():
captcha = s.get("http://localhost:55352/captcha.php")
return Image.open(BytesIO(captcha.content))
def send_guess(guess):
data = {
'code': guess
r = s.post("http://localhost:55352/", data=data)
return r.text

def get_md5img(im):
tilei = im.crop((0,0,10,30))
hash_img = hashlib.md5(tilei.tobytes()).hexdigest()
return hash_img

for i in range(150):
im = get_captcha()
hsum = get_md5img(im)
if hsum in mapping[0]:
guessed_number = mapping[0][hsum]

print "Extracted hash: " + hsum
print "Guessing number: " + str(guessed_number)
print send_guess(guessed_number)


# hide image
for proc in psutil.process_iter():
if proc.name() == "display":

Original writeup (https://github.com/flawwan/CTF-Writeups/blob/master/BTH_CTF_2019/Eat%20Sleep%20Smash%20Repeat/writeup.md).