AppArmor is a Linux kernel security module that enforces mandatory access control (MAC) policies to restrict programs' capabilities, thereby enhancing system security. By confining applications to predefined profiles, AppArmor limits their access to system resources, mitigating potential threats from both known and unknown vulnerabilities. Integrated into the mainline Linux kernel since version 2.6.36, AppArmor has been actively supported by Canonical since 2009. Key Features and Functionality: - Per-Program Profiles: AppArmor allows administrators to create specific security profiles for individual applications, defining permissible actions and resource access. - Path-Based Access Control: Unlike label-based systems, AppArmor utilizes file paths to enforce access controls, simplifying profile management and compatibility across different file systems. - Learning Mode: This mode logs policy violations without enforcing restrictions, enabling administrators to refine profiles based on actual application behavior before full enforcement. - Integration with Linux Security Modules (LSM): AppArmor is implemented using the LSM framework, ensuring seamless integration with the Linux kernel. Primary Value and Problem Solved: AppArmor enhances system security by providing a straightforward and effective method for implementing mandatory access controls. By restricting applications to their intended functionalities, it prevents exploitation of software vulnerabilities, including zero-day attacks. Its path-based approach and user-friendly profile management make it accessible for administrators, offering a less complex alternative to other MAC systems like SELinux. This ease of use, combined with robust security enforcement, makes AppArmor a valuable tool for protecting Linux systems against unauthorized access and potential threats.