What is the purpose of an access control list (ACL)?

An access control list (ACL) serves the essential purpose of defining and managing permissions for users or systems as it relates to specific resources within a system. It outlines who is allowed to access resources, such as files or network devices, and what actions they are permitted to take, such as reading, writing, or executing. The ACL acts as a rule set that dictates access parameters, enhancing security and ensuring that only authorized individuals or systems can perform designated actions on protected resources. This granularity in permission management is critical in safeguarding systems against unauthorized access and misuse.

The other options do not accurately reflect the primary function of an ACL. While managing user permissions to system configurations touches on permissions, it doesn't encompass the broader range of resource management that ACLs provide. Regarding responses to security incidents, that falls under incident response procedures rather than access control mechanisms. Lastly, tracking system performance and user activity typically involves auditing and monitoring tools, rather than the explicit permission definitions that an ACL focuses on.