A risk practitioner is implementing controls to protect privileged administrative access to a core finance system, applying defence in depth so the objective is not lost if one safeguard fails. Which implementation approach best reflects defence in depth for this objective?
- ADeploy the strongest available multi-factor authentication mechanism and concentrate the implementation effort on hardening that single control thoroughly
- BPlace a network firewall in front of the finance system so that all privileged access traffic must first pass through the perimeter device
- CSchedule a quarterly review of privileged accounts so any inappropriate access is detected and removed within the following review cycle
- DCombine multi-factor authentication, just-in-time access approval and independent session logging so a failure in one layer does not by itself grant uncontrolled access Correct
Why A is wrong: Investing heavily in one strong control is tempting, but defence in depth specifically avoids relying on a single layer, since its failure would then leave the objective exposed.
Why B is wrong: A perimeter firewall is one useful layer, but resting the whole objective on a single network control repeats the single-point-of-failure weakness defence in depth is meant to remove.
Why C is wrong: Periodic review is a valuable detective layer, but on its own it allows misuse to persist until the next cycle and does not provide the preventive depth the objective needs.
Why D is correct: Layering authentication, approval and monitoring controls means no single failure leaves privileged access uncontrolled, which is exactly what defence in depth seeks for a critical objective.