Windows Reverse Port Forwarding using C# / Powershell

README.MD

Socat

• On the lhost listening side you can use socat to create two server sockets.

socat -dd TCP-LISTEN:4444,reuseaddr,fork TCP-LISTEN:1234,reuseaddr

• Once WPF connected to port 4444, you can talk to 127.0.0.1:1234 as if it where the remote host.

wpf.cs

/*
Reverse port forwarder; connects reverse (left) to forward (right).

Find csc.exe:
	cd /d %SYSTEMROOT% && dir csc.exe /B /S
Compile example:
	C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe wpf.cs
*/
using System.IO;
using System.Net.Sockets;
using System;
using System.Net;
using System.Threading;

public class WPF
{
	private static bool Connected(Socket s) {
		if (!s.Poll(0, SelectMode.SelectRead) && s.Available == 0) {
			return true;
		}
		else {
			return false;
		}
	}

	public static int Main(string[] args)
	{
		bool keepRunning = true;

		if (args.Length < 4) {
			Console.WriteLine("Parameters: <lhost> <lport> <rhost> <rport>");
			return -1;
		}

		string lhost = args[0];
		int lport = Int32.Parse(args[1]);
		string rhost = args[2];
		int rport = Int32.Parse(args[3]);;

		Console.WriteLine(String.Format("Connecting {0}:{1} <==> {2}:{3}", lhost, lport, rhost, rport));

		TcpClient lclient = new TcpClient(lhost, lport);
		NetworkStream lstream = lclient.GetStream();
		Socket lsock = lclient.Client;

		TcpClient rclient;
		NetworkStream rstream;
		Socket rsock = null;

		Console.CancelKeyPress += delegate(object sender, ConsoleCancelEventArgs e) {
			keepRunning = false;
			Console.WriteLine("CTRL+C received");
		};

		while (keepRunning) {
			if (!WPF.Connected(lsock)) {
				Console.WriteLine(String.Format("Lost connection to: {0}:{1}", lhost, lport));
				keepRunning = false;
			}
			if ((rsock == null) || (!WPF.Connected(rsock))) {
				rclient = new TcpClient(rhost, rport);
				rstream = rclient.GetStream();
				rsock = rclient.Client;

				lstream.CopyToAsync(rstream);
				rstream.CopyToAsync(lstream);
			}
			Thread.Sleep(1000);
		}
		Console.WriteLine("Shutdown...");
		return 0;
	}
}

wpf.ps1

$cs = @"
using System.IO;
using System.Net.Sockets;
using System;
using System.Net;
using System.Threading;

public class WPF
{
	private static bool Connected(Socket s) {
		if (!s.Poll(0, SelectMode.SelectRead) && s.Available == 0) {
			return true;
		}
		else {
			return false;
		}
	}

	public static int Main(string[] args)
	{
		bool keepRunning = true;

		if (args.Length < 4) {
			Console.WriteLine("Parameters: <lhost> <lport> <rhost> <rport>");
			return -1;
		}

		string lhost = args[0];
		int lport = Int32.Parse(args[1]);
		string rhost = args[2];
		int rport = Int32.Parse(args[3]);;

		Console.WriteLine(String.Format("Connecting {0}:{1} <==> {2}:{3}", lhost, lport, rhost, rport));

		TcpClient lclient = new TcpClient(lhost, lport);
		NetworkStream lstream = lclient.GetStream();
		Socket lsock = lclient.Client;

		TcpClient rclient;
		NetworkStream rstream;
		Socket rsock = null;

		Console.CancelKeyPress += delegate(object sender, ConsoleCancelEventArgs e) {
			keepRunning = false;
			Console.WriteLine("CTRL+C received");
		};

		while (keepRunning) {
			if (!WPF.Connected(lsock)) {
				Console.WriteLine(String.Format("Lost connection to: {0}:{1}", lhost, lport));
				keepRunning = false;
			}
			if ((rsock == null) || (!WPF.Connected(rsock))) {
				rclient = new TcpClient(rhost, rport);
				rstream = rclient.GetStream();
				rsock = rclient.Client;

				lstream.CopyToAsync(rstream);
				rstream.CopyToAsync(lstream);
			}
			Thread.Sleep(1000);
		}
		Console.WriteLine("Shutdown...");
		return 0;
	}
}
"@;
Add-Type -Language CSharp $cs
[WPF]::Main(("10.10.14.1", "4444", "127.0.0.1", "8080"))