Book Image

SELinux System Administration, Third Edition - Third Edition

By : Sven Vermeulen
Book Image

SELinux System Administration, Third Edition - Third Edition

By: Sven Vermeulen

Overview of this book

Linux is a dominant player in many organizations and in the cloud. Securing the Linux environment is extremely important for any organization, and Security-Enhanced Linux (SELinux) acts as an additional layer to Linux system security. SELinux System Administration covers basic SELinux concepts and shows you how to enhance Linux system protection measures. You will get to grips with SELinux and understand how it is integrated. As you progress, you’ll get hands-on experience of tuning and configuring SELinux and integrating it into day-to-day administration tasks such as user management, network management, and application maintenance. Platforms such as Kubernetes, system services like systemd, and virtualization solutions like libvirt and Xen, all of which offer SELinux-specific controls, will be explained effectively so that you understand how to apply and configure SELinux within these applications. If applications do not exert the expected behavior, you’ll learn how to fine-tune policies to securely host these applications. In case no policies exist, the book will guide you through developing custom policies on your own. By the end of this Linux book, you’ll be able to harden any Linux system using SELinux to suit your needs and fine-tune existing policies and develop custom ones to protect any app and service running on your Linux systems.
Table of Contents (22 chapters)
1
Section 1: Using SELinux
8
Section 2: SELinux-Aware Platforms
14
Section 3: Policy Management

Investigating domain transitions

An important analytical approach when dealing with SELinux policies is to perform a domain transition analysis. Domains are bounded by the access controls in place for a given domain, but users or processes can transition to other domains by executing the right set of applications.

Analyzing whether and how a transition can occur between two SELinux domains allows administrators to validate the secure state of the policy. Given the mandatory nature of SELinux, adversaries will find it difficult to be able to execute target applications if a domain transition analysis shows that the source domain cannot execute said application, either directly or indirectly.

Administrators should use domain transition analysis to confirm a domain is correctly confined, and that vulnerabilities within the applications running inside a domain cannot lead to privilege escalations.

Using apol for domain transition analysis

After starting apol, select New Analysis...