The intensive search for a more secure operating system has often left everyday, production computers far behind their experimental, research cousins. Now SELinux (Security Enhanced Linux) dramatically changes this. This best-known and most respected security-related extension to Linux embodies the key advances of the security field. Better yet, SELinux is available in widespread and popular distributions of the Linux operating system–including for Debian, Fedora, Gentoo, Red Hat Enterprise Linux, and SUSE–all of it free and open source.
SELinux emerged from research by the National Security Agency and implements classic strong-security measures such as role-based access controls, mandatory access controls, and fine-grained transitions and privilege escalation following the principle of least privilege. It compensates for the inevitable buffer overflows and other weaknesses in applications by isolating them and preventing flaws in one application from spreading to others. The scenarios that cause the most cyber-damage these days–when someone gets a toe-hold on a computer through a vulnerability in a local networked application, such as a Web server, and parlays that toe-hold into pervasive control over the computer system–are prevented on a properly administered SELinux system.