When working with Windows Remote Desktop (RDP), developers often encounter a peculiar limitation - the inability to send the standard Ctrl+Alt+Del security sequence directly through the connection. This security measure, designed to protect local systems, becomes an obstacle when you need to perform administrative tasks on the remote machine.

Microsoft provides several methods to send Ctrl+Alt+Del to a remote session:

1. The official RDP client method:
   - Windows: Ctrl+Alt+End
   - MacOS: Fn+Ctrl+Alt+Backspace

2. Through the RDP toolbar:
   - Click the toolbar icon → "Send Ctrl+Alt+Del"

For automation scenarios, here are code-based approaches:

PowerShell Method

$wshell = New-Object -ComObject wscript.shell;
$wshell.SendKeys("^%{DELETE}")

C# Windows Forms Approach

using System;
using System.Windows.Forms;

public class RemoteInputSender {
    public static void SendCAD() {
        SendKeys.SendWait("^%{DELETE}");
    }
}

For custom RDP solutions, you can implement a virtual channel:

// C++ Virtual Channel example snippet
DWORD WINAPI VCAPIConnection::SendCADSequence() {
    CHANNEL_DEF channelDef;
    channelDef.name = "CADVirtualChannel";
    // Implementation would continue...
}

When implementing programmatic solutions:

• Always validate remote session security settings
• Never store credentials in code
• Consider using Windows Credential Manager API for password changes

If standard methods fail:

1. Check Group Policy settings (especially "Use the session's Ctrl+Alt+Del")
2. Verify Remote Desktop Services role configuration
3. Test with different RDP client versions

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When working with Remote Desktop (RDP), one of the most frustrating limitations is the inability to send the Ctrl+Alt+Del combination directly to the remote machine. This security sequence is intercepted by the local operating system before it reaches the RDP session. For developers managing remote servers or workstations, this creates obstacles when:

• Changing passwords (especially local admin credentials)
• Accessing Task Manager on remote machines
• Triggering secure attention sequences for UAC prompts

The built-in Windows Remote Desktop client provides several ways to send Ctrl+Alt+Del:

Method 1: Keyboard Shortcut

While connected to your RDP session:

Ctrl + Alt + End

This is the standard RDP equivalent of Ctrl+Alt+Del. It works in all modern Windows versions (Windows 7+) and most RDP clients.

Method 2: On-Screen Keyboard

For systems where the keyboard shortcut doesn't work:

1. Open Run dialog (Win + R)
2. Type: osk
3. Click Ctrl, Alt, then Del keys on the virtual keyboard

When building automation tools or working with multiple remote sessions, you might need programmatic control.

PowerShell Approach

For Windows-to-Windows remoting:

# Requires PowerShell Remoting enabled on target
$session = New-PSSession -ComputerName RemotePC
Invoke-Command -Session $session -ScriptBlock {
    # Simulate Ctrl+Alt+Del via NtUserSendInput
    Add-Type -TypeDefinition @"
    using System;
    using System.Runtime.InteropServices;
    public class KeyboardSend {
        [DllImport("user32.dll")]
        public static extern void keybd_event(byte bVk, byte bScan, uint dwFlags, UIntPtr dwExtraInfo);
    }
"@
    [KeyboardSend]::keybd_event(0x1D, 0, 0, UIntPtr.Zero);  # Ctrl
    [KeyboardSend]::keybd_event(0x38, 0, 0, UIntPtr.Zero);  # Alt
    [KeyboardSend]::keybd_event(0x2E, 0, 0, UIntPtr.Zero);  # Del
    Start-Sleep -Milliseconds 100
    [KeyboardSend]::keybd_event(0x2E, 0, 2, UIntPtr.Zero);  # Release Del
    [KeyboardSend]::keybd_event(0x38, 0, 2, UIntPtr.Zero);  # Release Alt
    [KeyboardSend]::keybd_event(0x1D, 0, 2, UIntPtr.Zero);  # Release Ctrl
}
Remove-PSSession $session

Alternative: AutoHotkey Script

For interactive use cases:

#IfWinActive ahk_class TscShellContainerClass
^!Del::
SendInput ^!{End}
return
#IfWinActive

This remaps Ctrl+Alt+Del to Ctrl+Alt+End when an RDP window is active.

For non-Windows clients connecting to Windows machines:

• macOS RDP clients: Use Fn+Ctrl+Alt+Delete
• Linux remmina: Ctrl+Alt+Enter sends the sequence
• FreeRDP: Add /kbd:0x00010001 flag for special key handling

While these solutions work, remember that Ctrl+Alt+Del interception is a security feature:

• Prevents credential theft via fake login screens
• Ensures secure attention sequence integrity
• Blocks malicious applications from capturing the combo

For production environments, consider using Group Policy to enable alternative secure login methods rather than bypassing this protection.