Book Image

Mastering Linux Security and Hardening - Third Edition

By : Donald A. Tevault
3.7 (7)
Book Image

Mastering Linux Security and Hardening - Third Edition

3.7 (7)
By: Donald A. Tevault

Overview of this book

The third edition of Mastering Linux Security and Hardening is an updated, comprehensive introduction to implementing the latest Linux security measures, using the latest versions of Ubuntu and AlmaLinux. In this new edition, you will learn how to set up a practice lab, create user accounts with appropriate privilege levels, protect sensitive data with permissions settings and encryption, and configure a firewall with the newest firewall technologies. You’ll also explore how to use sudo to set up administrative accounts with only the privileges required to do a specific job, and you’ll get a peek at the new sudo features that have been added over the past couple of years. You’ll also see updated information on how to set up a local certificate authority for both Ubuntu and AlmaLinux, as well as how to automate system auditing. Other important skills that you’ll learn include how to automatically harden systems with OpenSCAP, audit systems with auditd, harden the Linux kernel configuration, protect your systems from malware, and perform vulnerability scans of your systems. As a bonus, you’ll see how to use Security Onion to set up an Intrusion Detection System. By the end of this new edition, you will confidently be able to set up a Linux server that will be secure and harder for malicious actors to compromise.
Table of Contents (22 chapters)
1
Section 1: Setting up a Secure Linux System
9
Section 2: Mastering File and Directory Access Control (DAC)
12
Section 3: Advanced System Hardening Techniques
20
Other Books You May Enjoy
21
Index

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. So yes, you do need to guard against attacks from your organization’s own employees...