Access control list

Access Control List

An Access Control List (ACL) is a security mechanism used in computer systems and networks to manage and enforce permissions for accessing resources. It is a list of rules or entries that specifies which users, groups, or entities are granted or denied access to specific resources, such as files, folders, devices, or network services.

Overview

Access Control Lists provide granular control over resource access by defining who can perform what actions on which resources. Each entry in an ACL typically includes:

1. Subject: The user, group, or entity to which the access permissions apply.
2. Object: The resource or object being protected, such as a file, folder, or network service.
3. Permissions: The actions or operations allowed or denied for the subject on the object, such as read, write, execute, or delete.

Types

There are two main types of Access Control Lists:

1. Discretionary Access Control Lists (DAC): In DAC, access permissions are set and managed by the owner of the resource. Owners can grant or revoke access to their resources for other users or groups based on their discretion.
2. Mandatory Access Control Lists (MAC): In MAC, access permissions are centrally managed by a system administrator or security policy. Access decisions are based on predefined rules or labels assigned to users, groups, or resources, typically using security classifications such as "confidential," "secret," or "top secret."

Implementation

Access Control Lists can be implemented at various levels, including:

• File System ACLs: Used to control access to files and directories on file systems such as NTFS (Windows) and ext4 (Linux).
• Network ACLs: Used to control traffic flow and access to network resources, such as routers, switches, and firewalls.
• Database ACLs: Used to control access to database objects and data, such as tables, views, and stored procedures.
• Web Server ACLs: Used to control access to web resources, such as web pages, directories, and APIs.

Benefits

Access Control Lists offer several benefits, including:

• Granular Control: Fine-grained control over resource access based on user roles, groups, or individual identities.
• Flexibility: Ability to define and enforce complex access policies tailored to specific security requirements.
• Scalability: Scalable solution for managing access permissions across large and diverse computing environments.
• Auditing and Compliance: Enhanced visibility and accountability through access logs and compliance reporting.