Secure is the fact that
Ctrl+
Alt+
Del is the only key sequence that an operating system
will never allow to be redirected. No third party application can respond to this key combination to fake a login window and/or keylog your password for example.
Here's more...The true safety is provided by the concept of a secure desktop, for which the key combination is just a guarantee of enjoying that security.
In Windows, there are actually different types of desktops. The one that we work in is what we all call the desktop, but has been known by other names such as default, interactive, or application desktop. It is here that any given application can run.
The login screen is actually an entirely different kind of desktop, a secure desktop where only trusted processes are running as SYSTEM. While the key combination will guard against fake login screens, it does not protect against a virus infection that is keylogging all of your keystrokes. The desktop concept adds further protection here by not allowing such a background program access to what is happening on the secure desktop.
You can picture this isolation by remembering what happens to the default desktop when UAC prompts appear. You will notice that UAC prompts are actually in one of these secure desktops.
You can also imagine what the isolation means in terms of security when considering a virus that spoofs your mouse pointer. The UAC team blogged about such a scenario:
Enable or disable secure logon (Ctrl+Alt+Delete)It's important to keep your computer as secure as possible. One way to do this is to enable secure logon, which requires you to press Ctrl+Alt+Delete to log on. Using secure logon provides an additional layer of security for your computer by ensuring that the authentic Windows logon screen appears. When secure logon is enabled, another program (such as a virus or spyware) can't intercept your user name and password as you enter it.
1. Click the
Start button
, type
netplwiz in the search box, and then press
Enter.
If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
2. Click the
Advanced tab, select the
Require users to press Ctrl+Alt+Delete check box, and then click
OK.
htg
