Which method provides the highest level of security for application access in Azure AD?

Multi-factor authentication (MFA) provides the highest level of security for application access in Azure Active Directory (Azure AD) by adding an additional layer of verification beyond just a username and password. This significantly reduces the risk of unauthorized access to applications, as an attacker would need not only the user’s password but also a second factor, which could be a mobile app notification, a text message, a phone call, or a hardware token.

MFA ensures that even if a user's credentials are compromised, any attempts to access the application would still be thwarted unless the attacker also has access to the second factor of authentication. This is particularly crucial in today’s threat landscape, where password breaches are commonplace.

In contrast, methods like single sign-on facilitate convenient access, device compliance checks ensure that devices meet organizational policies, and conditional access policies add layers of controls based on user, location, or risk factors, but none of them provide the enhanced security that Multi-factor authentication does at the user access level. MFA directly addresses the primary threat of stolen credentials, making it the most effective method for securing application access in Azure AD.