Book Image

Mastering Linux Security and Hardening - Second Edition

By : Donald A. Tevault
Book Image

Mastering Linux Security and Hardening - Second Edition

By: Donald A. Tevault

Overview of this book

From creating networks and servers to automating the entire working environment, Linux has been extremely popular with system administrators for the last couple of decades. However, security has always been a major concern. With limited resources available in the Linux security domain, this book will be an invaluable guide in helping you get your Linux systems properly secured. Complete with in-depth explanations of essential concepts, practical examples, and self-assessment questions, this book begins by helping you set up a practice lab environment and takes you through the core functionalities of securing Linux. You'll practice various Linux hardening techniques and advance to setting up a locked-down Linux server. As you progress, you will also learn how to create user accounts with appropriate privilege levels, protect sensitive data by setting permissions and encryption, and configure a firewall. The book will help you set up mandatory access control, system auditing, security profiles, and kernel hardening, and finally cover best practices and troubleshooting techniques to secure your Linux environment efficiently. By the end of this Linux security book, you will be able to confidently set up a Linux server that will be much harder for malicious actors to compromise.
Table of Contents (20 chapters)
1
Section 1: Setting up a Secure Linux System
8
Section 2: Mastering File and Directory Access Control (DAC)
11
Section 3: Advanced System Hardening Techniques

Understanding process isolation

A primary objective of any network intruder is to gain the privileges that are required to perform his or her dirty deeds. This normally involves logging in as a normal user and then performing some sort of privilege escalation. A vertical escalation involves obtaining root privileges, while a horizontal escalation involves gaining the privileges of some other normal user. If the other normal user has any sensitive documents in folders that he or she can access, then a horizontal escalation might be all that the intruder requires. Discretionary Access Control and Mandatory Access Control can help out, but we also want to isolate processes from each other and ensure that processes run with only the lowest possible privileges.

When planning a defense against these types of attacks, consider that the attacks could come from either outsiders or insiders...