ASPX/CommandExecutor.aspx at main · petherl/ASPX · GitHub

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<%@ Page Language="C#" AutoEventWireup="true" %>
<%@ Import Namespace="System.Diagnostics" %>
<%@ Import Namespace="System.Text.RegularExpressions" %>
<%@ Import Namespace="System.Security.Principal" %>

<!DOCTYPE html>
<html>
<head>
    <title>Educational Command Execution System</title>
    <style>
        body { font-family: 'Consolas', 'Monaco', monospace; margin: 0; padding: 20px; background: #1a1a1a; color: #00ff00; }
        .container { max-width: 1200px; margin: 0 auto; background: #000; border: 2px solid #00ff00; border-radius: 10px; padding: 20px; box-shadow: 0 0 20px rgba(0,255,0,0.3); }
        .header { text-align: center; margin-bottom: 30px; border-bottom: 1px solid #00ff00; padding-bottom: 20px; }
        .terminal { background: #000; border: 1px solid #333; border-radius: 5px; padding: 15px; margin: 15px 0; font-family: 'Consolas', monospace; }
        .command-input { width: 100%; background: #111; color: #00ff00; border: 1px solid #333; padding: 10px; font-family: 'Consolas', monospace; font-size: 14px; border-radius: 3px; }
        .output { background: #000; color: #00ff00; padding: 15px; border: 1px solid #333; border-radius: 3px; white-space: pre-wrap; font-family: 'Consolas', monospace; font-size: 12px; max-height: 400px; overflow-y: auto; }
        .btn { background: #333; color: #00ff00; border: 1px solid #00ff00; padding: 10px 20px; cursor: pointer; font-family: 'Consolas', monospace; border-radius: 3px; margin: 5px; }
        .btn:hover { background: #00ff00; color: #000; }
        .warning { background: #ff4444; color: white; padding: 15px; border-radius: 5px; margin: 15px 0; }
        .info { background: #0066cc; color: white; padding: 10px; border-radius: 3px; margin: 10px 0; }
        .security-panel { background: #330000; border: 1px solid #ff0000; padding: 15px; border-radius: 5px; margin: 15px 0; }
        .allowed-commands { background: #003300; border: 1px solid #00ff00; padding: 10px; border-radius: 3px; margin: 10px 0; }
    </style>
</head>
<body>
    <div class="container">
        <div class="header">
            <h1>⚡ Educational Command Execution System</h1>
            <p>Secure command execution with comprehensive validation and monitoring</p>
        </div>

        <!-- Critical Security Warning -->
        <div class="warning">
            <strong>⚠️ CRITICAL SECURITY WARNING:</strong> This system demonstrates command execution concepts for educational purposes only.
            Production systems must implement strict authentication, command whitelisting, sandboxing, and comprehensive audit logging.
            Never deploy command execution interfaces without proper security controls.
        </div>

        <form id="commandForm" runat="server">
            <!-- Security Information Panel -->
            <div class="security-panel">
                <h3>🔒 Security Features Implemented:</h3>
                <ul>
                    <li>Command validation and sanitization</li>
                    <li>Whitelist-based command filtering</li>
                    <li>Output length limitations</li>
                    <li>Execution timeout controls</li>
                    <li>Comprehensive audit logging</li>
                    <li>User context validation</li>
                </ul>
            </div>

            <!-- Allowed Commands Reference -->
            <div class="allowed-commands">
                <h3>✅ Allowed Commands (Educational Whitelist):</h3>
                <p><strong>System Info:</strong> systeminfo, whoami, hostname, date, time</p>
                <p><strong>Directory:</strong> dir, ls (limited to safe directories)</p>
                <p><strong>Network:</strong> ping (limited), ipconfig /all</p>
                <p><strong>Process:</strong> tasklist (view only)</p>
            </div>

            <!-- Command Input Section -->
            <div class="terminal">
                <h3>💻 Command Terminal</h3>

                <div style="margin-bottom: 15px;">
                    <label for="txtCommand">Enter Command:</label><br>
                    <asp:TextBox ID="txtCommand" runat="server" CssClass="command-input"
                        placeholder="Type your command here (e.g., systeminfo, dir, ping google.com)" />
                </div>

                <div style="margin-bottom: 15px;">
                    <label for="ddlExecutionMode">Execution Mode:</label><br>
                    <asp:DropDownList ID="ddlExecutionMode" runat="server" CssClass="command-input" style="width: auto;">
                        <asp:ListItem Value="safe" Text="Safe Mode (Recommended)" Selected="True" />
                        <asp:ListItem Value="restricted" Text="Restricted Mode" />
                    </asp:DropDownList>
                </div>

                <div style="margin-bottom: 15px;">
                    <asp:CheckBox ID="chkConfirmExecution" runat="server" Text="I understand the security implications" />
                    <asp:RequiredFieldValidator ID="rfvConfirm" runat="server"
                        ControlToValidate="chkConfirmExecution"
                        ErrorMessage="Please confirm you understand the security implications"
                        ForeColor="#ff4444" ValidationGroup="ExecuteGroup" />
                </div>

                <asp:Button ID="btnExecute" runat="server" Text="▶️ Execute Command"
                    CssClass="btn" OnClick="ExecuteCommand_Click" ValidationGroup="ExecuteGroup" />

                <asp:Button ID="btnClear" runat="server" Text="🗑️ Clear Output"
                    CssClass="btn" OnClick="ClearOutput_Click" />
            </div>

            <!-- Command Output Section -->
            <div class="terminal">
                <h3>📤 Command Output</h3>
                <asp:Panel ID="pnlOutput" runat="server">
                    <div class="output" id="outputArea">
                        <asp:Label ID="lblOutput" runat="server" />
                    </div>
                </asp:Panel>
            </div>

            <!-- System Information Display -->
            <div class="info">
                <strong>System Context:</strong>
                User: <%= Environment.UserName %> |
                Machine: <%= Environment.MachineName %> |
                OS: <%= Environment.OSVersion %> |
                Time: <%= DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss") %>
            </div>
        </form>
    </div>
</body>
</html>

<script runat="server">
    // Educational: Define allowed commands for security
    private readonly Dictionary<string, string[]> AllowedCommands = new Dictionary<string, string[]>
    {
        ["systeminfo"] = new[] { "systeminfo" },
        ["whoami"] = new[] { "whoami" },
        ["hostname"] = new[] { "hostname" },
        ["date"] = new[] { "date", "date /t" },
        ["time"] = new[] { "time", "time /t" },
        ["dir"] = new[] { "dir", "dir /w", "dir /p" },
        ["ipconfig"] = new[] { "ipconfig", "ipconfig /all" },
        ["ping"] = new[] { "ping" }, // Special handling required
        ["tasklist"] = new[] { "tasklist", "tasklist /fo table" }
    };

    // Educational: Security constraints
    private readonly int MaxOutputLength = 10000; // Limit output size
    private readonly int CommandTimeoutSeconds = 30; // Prevent long-running commands

    /// <summary>
    /// Handles secure command execution with comprehensive validation
    /// Educational implementation demonstrating secure command execution practices
    /// </summary>
    protected void ExecuteCommand_Click(object sender, EventArgs e)
    {
        try
        {
            // Validate user confirmation
            if (!chkConfirmExecution.Checked)
            {
                ShowOutput("❌ Please confirm you understand the security implications.", false);
                return;
            }

            // Get and validate command input
            string rawCommand = txtCommand.Text?.Trim();
            if (string.IsNullOrEmpty(rawCommand))
            {
                ShowOutput("❌ Please enter a command to execute.", false);
                return;
            }

            // Security validation: Check command against whitelist
            if (!IsCommandAllowed(rawCommand))
            {
                ShowOutput($"❌ Command '{rawCommand}' is not allowed. Please use only whitelisted commands.", false);
                LogSecurityViolation(rawCommand, "COMMAND_NOT_ALLOWED");
                return;
            }

            // Sanitize and prepare command
            string sanitizedCommand = SanitizeCommand(rawCommand);
            string executionMode = ddlExecutionMode.SelectedValue;

            // Log command execution attempt
            LogCommandExecution(sanitizedCommand, executionMode, "ATTEMPT");

            // Execute command with security controls
            string output = ExecuteSecureCommand(sanitizedCommand, executionMode);

            // Display results
            ShowOutput($"Command: {sanitizedCommand}\n\n{output}", true);

            // Log successful execution
            LogCommandExecution(sanitizedCommand, executionMode, "SUCCESS");

            // Clear confirmation checkbox for security
            chkConfirmExecution.Checked = false;
        }
        catch (Exception ex)
        {
            string errorMessage = $"❌ Execution failed: {ex.Message}";
            ShowOutput(errorMessage, false);
            LogCommandExecution(txtCommand.Text, ddlExecutionMode.SelectedValue, "ERROR", ex.Message);
        }
    }

    /// <summary>
    /// Validates if a command is allowed based on security whitelist
    /// Educational implementation of command validation
    /// </summary>
    private bool IsCommandAllowed(string command)
    {
        if (string.IsNullOrWhiteSpace(command))
            return false;

        // Convert to lowercase for comparison
        string lowerCommand = command.ToLower().Trim();

        // Check against allowed commands
        foreach (var allowedCategory in AllowedCommands)
        {
            foreach (var allowedCmd in allowedCategory.Value)
            {
                if (lowerCommand.StartsWith(allowedCmd.ToLower()))
                {
                    // Special validation for ping command
                    if (allowedCategory.Key == "ping")
                    {
                        return ValidatePingCommand(lowerCommand);
                    }
                    return true;
                }
            }
        }

        return false;
    }

    /// <summary>
    /// Special validation for ping commands to prevent abuse
    /// Educational implementation of parameter validation
    /// </summary>
    private bool ValidatePingCommand(string command)
    {
        // Allow only basic ping with hostname/IP
        Regex pingPattern = new Regex(@"^ping\s+([a-zA-Z0-9\-\.]+)(\s+-[nt]\s+\d+)?$", RegexOptions.IgnoreCase);
        return pingPattern.IsMatch(command);
    }

    /// <summary>
    /// Sanitizes command input to prevent injection attacks
    /// Educational implementation of input sanitization
    /// </summary>
    private string SanitizeCommand(string command)
    {
        if (string.IsNullOrEmpty(command))
            return string.Empty;

        // Remove potentially dangerous characters and sequences
        string sanitized = command.Trim();

        // Remove command chaining attempts
        sanitized = Regex.Replace(sanitized, @"[;&|`$(){}[\]\\]", "");

        // Remove redirection attempts
        sanitized = Regex.Replace(sanitized, @"[<>]", "");

        // Limit length
        if (sanitized.Length > 100)
            sanitized = sanitized.Substring(0, 100);

        return sanitized;
    }

    /// <summary>
    /// Executes commands with security controls and monitoring
    /// Educational implementation of secure process execution
    /// </summary>
    private string ExecuteSecureCommand(string command, string executionMode)
    {
        try
        {
            // Create process with security settings
            ProcessStartInfo startInfo = new ProcessStartInfo
            {
                FileName = "cmd.exe",
                Arguments = "/c " + command,
                UseShellExecute = false,
                RedirectStandardOutput = true,
                RedirectStandardError = true,
                CreateNoWindow = true,

                // Educational: Set working directory to safe location
                WorkingDirectory = Server.MapPath("~/App_Data/")
            };

            // Apply execution mode restrictions
            if (executionMode == "restricted")
            {
                // Additional restrictions for restricted mode
                startInfo.WindowStyle = ProcessWindowStyle.Hidden;
            }

            using (Process process = new Process { StartInfo = startInfo })
            {
                // Start process with timeout
                process.Start();

                // Read output with length limitation
                string output = ReadProcessOutput(process);
                string errorOutput = ReadProcessError(process);

                // Wait for completion with timeout
                bool completed = process.WaitForExit(CommandTimeoutSeconds * 1000);

                if (!completed)
                {
                    process.Kill();
                    return "❌ Command execution timed out and was terminated for security.";
                }

                // Combine output and error streams
                string fullOutput = output;
                if (!string.IsNullOrEmpty(errorOutput))
                {
                    fullOutput += "\n\n--- Error Output ---\n" + errorOutput;
                }

                return string.IsNullOrEmpty(fullOutput) ? "Command executed successfully (no output)" : fullOutput;
            }
        }
        catch (Exception ex)
        {
            return $"❌ Execution error: {ex.Message}";
        }
    }

    /// <summary>
    /// Reads process output with length limitations for security
    /// Educational implementation of output control
    /// </summary>
    private string ReadProcessOutput(Process process)
    {
        try
        {
            string output = process.StandardOutput.ReadToEnd();

            // Limit output length for security and performance
            if (output.Length > MaxOutputLength)
            {
                output = output.Substring(0, MaxOutputLength) +
                        $"\n\n--- Output truncated at {MaxOutputLength} characters for security ---";
            }

            return output;
        }
        catch
        {
            return "Error reading command output";
        }
    }

    /// <summary>
    /// Reads process error output with length limitations
    /// Educational implementation of error handling
    /// </summary>
    private string ReadProcessError(Process process)
    {
        try
        {
            string errorOutput = process.StandardError.ReadToEnd();

            if (errorOutput.Length > MaxOutputLength / 2)
            {
                errorOutput = errorOutput.Substring(0, MaxOutputLength / 2) +
                             "\n--- Error output truncated ---";
            }

            return errorOutput;
        }
        catch
        {
            return "Error reading error output";
        }
    }

    /// <summary>
    /// Clears the command output display
    /// Educational implementation of UI state management
    /// </summary>
    protected void ClearOutput_Click(object sender, EventArgs e)
    {
        lblOutput.Text = "";
        ShowOutput("Output cleared.", true);
    }

    /// <summary>
    /// Displays command output with appropriate formatting
    /// Educational implementation of output presentation
    /// </summary>
    private void ShowOutput(string output, bool isSuccess)
    {
        string timestamp = DateTime.Now.ToString("HH:mm:ss");
        string statusIcon = isSuccess ? "✅" : "❌";

        string formattedOutput = $"[{timestamp}] {statusIcon}\n{output}\n{new string('-', 50)}\n";

        // Append to existing output
        lblOutput.Text += Server.HtmlEncode(formattedOutput);
    }

    /// <summary>
    /// Logs command execution for security auditing
    /// Educational implementation of security logging
    /// </summary>
    private void LogCommandExecution(string command, string mode, string status, string error = null)
    {
        try
        {
            string logEntry = $"[{DateTime.Now:yyyy-MM-dd HH:mm:ss}] " +
                            $"COMMAND_{status}: '{command}' | " +
                            $"Mode: {mode} | " +
                            $"User: {Environment.UserName} | " +
                            $"IP: {Request.UserHostAddress} | " +
                            $"UserAgent: {Request.UserAgent}";

            if (!string.IsNullOrEmpty(error))
            {
                logEntry += $" | Error: {error}";
            }

            string logPath = Server.MapPath("~/App_Data/CommandExecution.log");
            Directory.CreateDirectory(Path.GetDirectoryName(logPath));
            File.AppendAllText(logPath, logEntry + Environment.NewLine);
        }
        catch
        {
            // Educational: Silent failure for logging
        }
    }

    /// <summary>
    /// Logs security violations for monitoring
    /// Educational implementation of security incident logging
    /// </summary>
    private void LogSecurityViolation(string command, string violationType)
    {
        try
        {
            string logEntry = $"[{DateTime.Now:yyyy-MM-dd HH:mm:ss}] " +
                            $"SECURITY_VIOLATION: {violationType} | " +
                            $"Command: '{command}' | " +
                            $"User: {Environment.UserName} | " +
                            $"IP: {Request.UserHostAddress} | " +
                            $"UserAgent: {Request.UserAgent}";

            string logPath = Server.MapPath("~/App_Data/SecurityViolations.log");
            Directory.CreateDirectory(Path.GetDirectoryName(logPath));
            File.AppendAllText(logPath, logEntry + Environment.NewLine);
        }
        catch
        {
            // Educational: Silent failure for logging
        }
    }
</script>