On Windows one can enforce pressing Ctrl+Alt+Del to fire an interrupt that brings up the login window.When logging onto a console of a Linux computer: How can I tell if this login is a real one or a mocked up on to steal my credentials?
How to tell if console login is genuine?
linux;security;login
Assuming that you want to be protected against other normal users of thesystem (if the adversary has root access, all bets are off), yourcould in principle use a secure attentionkey:An operating system's Secure Attention Key is a security tool which is  provided as protection against trojan password capturing programs.  It  is an undefeatable way of killing all programs which could be  masquerading as login applications.  Users need to be taught to enter  this key sequence before they log in to the system.(Linux 2.4.2 Secure Attention Key (SAK) handling, Andrew Morton, 18 March 2001)This related U&L question may be of interest: How can I find the Secure Attention Key (SAK) on my system and can I disable it?