What is Access Control Lists (ACL)?

Access Control Lists (ACLs) are fundamental security mechanisms used to manage and control access to resources. They work by defining permissions that specify which users or groups are allowed to perform specific actions (e.g., read, write, execute) on a particular resource (e.g., files, directories, network ports). ACLs provide a more granular level of control compared to simpler permission models, allowing for fine-grained access management. They are commonly used in operating systems, file systems, network devices (routers, firewalls), and databases to enforce security policies.