Disable Ctrl+Alt+Del on Windows 7

Question

I know this question has been asked a few times and in a few different ways. However, across all the questions and answers, no one has been able to answer completely given

Answer 1

You can disable CAD through group policy: HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon set this value to 1.

or, through the advanced user accounts menu:

1. Open the Start Menu.

2. In the search line, type netplwiz and press Enter.

3. Click on the Advanced tab.

4. To Enable Secure Log On A) Check the Require users to press Ctrl+Alt+Delete box. NOTE: If the setting is grayed out, then see OPTION THREE or OPTION TWO below.

B) Go to step 6. 5. To Disable Secure Log On A) Uncheck the Requires users to press Ctrl+Alt+Delete box. NOTE: If the setting is grayed out, then see OPTION THREE or OPTION TWO below. 6. Click on OK.

Answer 2

Except for remapping/disabling keys, it is not possible to prevent Ctrl + Alt + Delete handling outside of kernel level code. I think this is fundamental security design feature of windows NT (and all derivatives). (Reasoning here.)

I would suggest writing a custom keyboard filter or device driver (or looking for an existing one perhaps). Not an easy task, but doable. Example resources:

• Keyboard Filter Driver for Windows Embedded Standard 7 - by Elbacom
• Interception (source) - A programming interface for intercepting input device communication.
• Writing a keyboard device driver

That first link to the Elbacom blog, in particular, could be useful since you are also targeting windows 7 embedded.

The second link, to Interception, is newer and might also be quite useful. It provides the kernel level module and abstracts some of the handling.

As a possible alternative, consider that though you can't disable the Ctrl + Alt + Delete hook without a device driver/filter, you can prevent all of the tasks that are accessible via that hook per changes to registry or with group policy editor. A previous edit of this answer linked to a utility called "Tweak Ctrl-Alt-Del Options" that made it very easy to disable all activities accessible via Ctrl-Alt-Del. That utility is no longer available from the original source, but is still find-able and there are others like it.

Answer 3

This article http://www.codeproject.com/Articles/7392/Lock-Windows-Desktop seems to have some good guidance there. The one I think will likely work : a) Replace the shell for system in the registry. That will mean that Explorer is not the one running as the default desktop. That might let you handle Ctrl+Alt+Del b) Force your application to run in a different desktop than the default. That will prevent the user from switching from it until the application is done.

All this assumes that you have complete control over that machine.