How to Secure Your Linux Servers With SELinux

SELinux can help you secure your server from malfunctioning processes or applications. Developed by the NSA (National Security Agency) to secure government devices from attackers, the security enhanced (SE) Linux architecture uses security protocols to restrict access to system resources. Find out how you can use it for your own server.

SELinux is a kernel module that can be enabled or disabled by the system admin. As the access to files and network ports is limited following a security policy, a faulty program or a misconfigured daemon can’t make a huge impact on system security.

When an application or process requests file access in the SELinux system, first it checks the access vector cache (AVC). If permission is previously cached, then it returns with the file that the application is requested for. If the permission is not cached, then it sends the request to the security server. The security server checks all the security policies in its database. Depending on the security policy, permission is then granted or declined.