Which security module is known for implementing mandatory access controls in Linux systems?

The security module recognized for implementing mandatory access controls (MAC) in Linux systems is SELinux. SELinux, or Security-Enhanced Linux, is a security architecture integrated into the kernel that enforces the separation of information based on confidentiality and integrity requirements. Through its policy layers, SELinux controls which users and processes can access certain files and resources, thereby adding an extra layer of security beyond traditional discretionary access controls (DAC).

With SELinux, administrators can define specific policies that dictate how processes interact with each other, along with what resources they can access. It operates in different modes, such as enforcing, permissive, and disabled, allowing for flexibility in how security is applied and monitored during system operation.

While AppArmor is another security module that provides an alternative method for enforcing mandatory access controls, it does not have the same complex and granular policy capabilities as SELinux. PAM (Pluggable Authentication Modules) is focused on authentication processes, while Firewalld is a dynamic firewall management tool that allows system administrators to configure firewall rules. Therefore, SELinux stands out as the primary module for enforcing mandatory access controls in Linux environments.