A security architect is designing a system where user access rights are reviewed and certified on a regular basis by data owners. The goal is to ensure that users continue to have only the permissions necessary to perform their job functions and that no excessive permissions exist. Which security principle is primarily being implemented through these regular reviews?
Least privilege means granting users the minimum level of access required. Regular access reviews are a key governance practice to uphold least privilege by detecting and removing excessive permissions.
Why this answer
Regular access reviews directly enforce the principle of least privilege by ensuring users retain only the permissions necessary for their current job functions. This process identifies and removes excessive permissions that may have accumulated over time, aligning with the core goal of minimizing the attack surface. In Microsoft 365, this is often implemented through Azure AD access reviews, where data owners certify or revoke user access.
Exam trap
The trap here is that candidates may confuse the periodic review of permissions with the zero trust model, but zero trust focuses on continuous verification at each access request rather than periodic certification of existing rights.
Why the other options are wrong
Defense in depth is a layered security strategy using multiple controls (e.g., firewalls, antivirus, encryption) to protect assets, not specifically about reviewing and certifying user permissions to enforce minimal access.
Zero trust is a security model that assumes no implicit trust and continuously verifies every access request, but the question specifically focuses on regular reviews and certifications to enforce minimal permissions, which is the principle of least privilege.
Separation of duties prevents fraud by requiring multiple people to complete a sensitive task, but it does not directly address the regular review and certification of user permissions to remove excessive access, which is the core of least privilege.