Linux handles security through three basic concepts, SELinux, chroot jail and iptables. Each concept is designed to target a specific need in the security spectrum. SELinux works at the kernel level and enforces mandatory access control, chroot jail works within the file system and iptables handles routing of data. In the following paragraphs I will discuss some details of each discipline.

SELinux can be traced back to the National Security Agency (NSA) when they got involved in trying to create a secure architecture. They released there research to the open source community which picked it up and continues to make improvements to its basic architecture. SELinux is designed to work at the kernel level of an operating system to enforce mandatory access control policies that confine users and servers to the minimum amount of privilege they require to do their job. The concept was to lock everything down by default and selectively allow access to applications as needed. This prevented security loop holes from remaining open because the average user wouldn’t know what to have running and what to have shut down. This way as users attempt to use an application SELinux will deny the attempt unless you can authorize its use. This gave administrators better security on their workstations from inadvertent malicious use or outright attack. One unique feature that makes SELinux different from standard anti-virus and spyware is its ability to be proactive rather than reactive. Anti-virus and spyware are designed to defend against attacks that it knows about which means its reacting to a known threat. However the weakness is that it has to be updated constantly to keep current with the newest attack.

Chroot jail on Linux is an operation that changes the apparent root directory for the current running process and its children A program that is run in such a modified