An access control policy is a fundamental cybersecurity mechanism that defines a set of rules governing which users, systems, or entities can access specific resources within an information system. These policies specify the type of access permitted—such as read, write, or execute—and establish the conditions under which access is granted. The primary purpose is to protect sensitive data and critical infrastructure from unauthorized exposure, modification, or disruption, thereby maintaining the core security principles of confidentiality, integrity, and availability.

In modern cloud and enterprise environments, access control policies are essential for managing permissions across distributed systems, including virtual machines, cloud services, data repositories, and network components. They ensure that only authenticated and authorized principals can perform specific actions on protected resources. Effective policies are strategically designed to align with organizational security objectives, mitigate risks, enforce regulatory compliance, and provide a resilient defense layer against both internal and external threats.