Zero Trust and Cloud Security Assurance

Cloud migration changes the security boundary. Network location alone can no longer provide the assurance that traditional perimeter based models assumed, because users, workloads and services increasingly interact across multiple networks, environments and trust boundaries.

NIST, the US National Institute of Standards and Technology, defines Zero Trust as removing implicit trust based solely on physical or network location and shifting the focus of protection towards users, assets and resources. CISA, the US Cybersecurity and Infrastructure Security Agency, adds that Zero Trust builds on existing network protections. Firewalls, segmentation and private connections still matter, but network location alone should no longer determine whether access is trusted.

Zero Trust provides a set of principles around which access governance can be built, covering who or what can reach a resource, under what conditions, and how that decision is enforced and reviewed.

Translated into board assurance, those principles become three questions for security leadership. Who is accountable for the policy governing access to our critical cloud workloads? Can management demonstrate that privileged and other high risk access to those workloads is limited to what is necessary? How frequently is that access reviewed, and what happens when exceptions or inappropriate access are identified?

If security leadership can answer these questions from routine board reporting, the access governance model is visible at board level. If answering them requires special preparation, there is an assurance gap between operational access management and board oversight.

Strong technical access controls do not, on their own, provide board assurance. The board's test is whether management can demonstrate through routine governance and reporting that access to critical cloud workloads is controlled, reviewed and accountable.