What is an Access Control List (ACL) primarily used for?

An Access Control List (ACL) serves the primary function of defining permissions and determining which subjects (such as users or devices) are authorized to access specific objects (such as files or network resources). By specifying allowed or denied access rights for different users or groups, ACLs are essential for implementing security policies within a system or network environment.

This capability is crucial for protecting sensitive information and ensuring that only authorized personnel can interact with critical resources. ACLs are commonly used in operating systems, firewalls, and network routers to enforce access controls effectively. They work in conjunction with authentication mechanisms to ensure that once a user is authenticated, their access rights are governed by the specified ACLs.

In contrast, other options address different security aspects. Listing unauthorized access attempts pertains to monitoring and logging, while controlling network traffic typically involves firewalls and routing policies rather than ACLs alone. Identifying system vulnerabilities involves risk assessment practices that are broader than access control measures. Thus, the primary utility of an ACL is centered on authorizing subjects for object access.