[1] As its security architecture concept, it can be implemented with any technical safeguards suitable for particular environment and risk profile.
In Common Criteria[2] and European Union electronic signature standards trusted path and trusted channel describe techniques that prevent interception or tampering with sensitive data as it passes through various system components: One of popular techniques for password stealing in Microsoft Windows was login spoofing, which was based on programs that simulated operating system's login prompt.
As a safeguard Windows NT introduced Ctrl-Alt-Del sequence as secure attention key to escape any third party programs and invoke system login prompt.
[3] A similar problem arises in case of websites requiring authentication, where the user is expected to enter their credentials without actually knowing if the website is not spoofed.
HTTPS mitigates this attack by first authenticating the server to the user (using trust anchor and certification path validation algorithm), and only then displaying the login form.