Linux PAM Architecture
Linux PAM (Pluggable Authentication Modules) is a modular framework that abstracts authentication mechanisms, enabling administrators to configure and control how users authenticate to applications or services. It works by providing a set of shared libraries that applications can call to perform authentication, account management, session setup, and password management. PAM's architecture is highly flexible: configuration files in /etc/pam.d/ or /etc/pam.conf specify which modules to use and in what order, allowing seamless integration of methods like password authentication, biometric systems, or LDAP. The key benefit is its modularity—administrators can easily add, modify, or remove authentication mechanisms without altering application code. In practice, PAM is widely used for managing system logins, SSH authentication, sudo permissions, and other secure operations, offering granular control over access policies and user authentication workflows.
