Windows Credential User Interface with secure attention sequence: not even bad

Ever since I used Windows NT (for me, the first Windows NT I used is Windows XP), I’ve been familiar with the importance of Ctrl+Alt+Delete. The combination is known as the secure attention sequence for Windows. In an uninfected copy of Windows, the sequence is handled exclusively by Windows, and is used to thwart trojan dialogs luring users’ credentials. Requiring SAS before Welcome Screen is a quite usable security feature. However, it is not the case for Credential User Interface.