What component of Linux helps in managing applications' permissions and restrictions at a granular level?

AppArmor is a security module for the Linux kernel that provides a way to set granular permissions and restrictions on applications. It allows you to enforce security policies that restrict how a program can interact with the rest of the system, including which files it can access and what system resources it can use. This makes it particularly useful for confining applications, reducing the risk posed by vulnerable software and mitigating potential damage from exploits.

The key aspect of AppArmor is its profile-based approach, where each application can have a defined profile that specifies what operations it is allowed to perform. This enhances security by minimizing the permissions each application requires to function, thereby limiting the potential impact of any security breaches.

While file permissions, kernel security, and Access Control Lists (ACLs) are related to managing permissions and security in Linux as well, AppArmor specifically targets application-level policies with a focus on detailed control over application behavior, which is why it is the correct choice in this context.