If you write a piece of malware that spoofs the secure desktop prompt, then you can steal the users password or whatever. But that does not grant you higher pri

If you write a piece of malware that spoofs the secure desktop prompt, then you can steal the users password or whatever. But that does not grant you higher privileges. Only the secure desktop can grant your process higher privileges. The password only authenticates you. It does not authorize you. So now your malware tries to use the credentials it stole to perform a restricted task afterword, but it will not have the proper privileges (elevated security token), so the user will get forced into the UAC prompt on the Secure Desktop. You cannot stop this from happening once you attempt to do it. The exact scenario you are describing, spoofing the secure desktop prompt, was literally the basics of the UAC prompt thought up over 15 years ago. It's like the 101 example. In contrast, on Linux, if you put a shell script in the users $PATH called 'sudo' that simply captures their password, you can (assuming the default PAM configuration) immediately use that to elevate privileges anytime you want with absolutely no intervention whatsoever. Because the password not only authenticates you, it authorizes you as well.