Benefits of running SELinux

http://docs.fedoraproject.org/en-US/Fedora/13/html/Security-Enhanced_Linux/chap-Security-Enhanced_Linux-Introduction.html#sect-Security-Enhanced_Linux-Introduction-Benefits_of_running_SELinux

2.1. Benefits of running SELinux

All processes and files are labeled with a type. A type defines a domain for processes, and a type for files. Processes are separated from each other by running in their own domains, and SELinux policy rules define how processes interact with files, as well as how processes interact with each other. Access is only allowed if an SELinux policy rule exists that specifically allows it.

Fine-grained access control. Stepping beyond traditional UNIX® permissions that are controlled at user discretion and based on Linux user and group IDs, SELinux access decisions are based on all available information, such as an SELinux user, role, type, and, optionally, a level.

SELinux policy is administratively-defined, enforced system-wide, and is not set at user discretion.

Reduced vulnerability to privilege escalation attacks. One example: since processes run in domains, and are therefore separated from each other, and because SELinux policy rules define how processes access files and other processes, if a process is compromised, the attacker only has access to the normal functions of that process, and to files the process has been configured to have access to. For example, if the Apache HTTP Server is compromised, an attacker can not use that process to read files in user home directories, unless a specific SELinux policy rule was added or configured to allow such access.

Confined services. SELinux ships with the ability to confine services and daemons so that they are more predictable and are only allowed access that is required for their normal operation.

SELinux can be used to enforce data confidentiality and integrity, as well as protecting processes from untrusted inputs.

SELinux is not:

antivirus software.

a replacement for passwords, firewalls, or other security systems.

an all-in-one security solution.

SELinux is designed to enhance existing security solutions, not replace them. Even when running SELinux, it is important to continue to follow good security practices, such as keeping software up-to-date, using hard-to-guess passwords, firewalls, and so on.