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

Configuring the sysctl.conf file

There are some significant differences between the default configurations of Ubuntu and CentOS/AlmaLinux. They all use the /etc/sysctl.conf file, but on CentOS and AlmaLinux, that file doesn’t have anything except for some explanatory comments. Ubuntu and CentOS/AlmaLinux all have files with default settings in the /usr/lib/sysctl.d/ directory, but there are more for CentOS and AlmaLinux than there are for Ubuntu. On Ubuntu, you’ll find other files with default values in the /etc/sysctl.d/ directory. On CentOS and AlmaLinux, that directory only contains a symbolic link that points back to the /etc/sysctl.conf file. Also, you’ll find that some things are hardcoded into the Linux kernel and aren’t mentioned in any of the configuration files. In true Linux fashion, every distro has a different way of configuring all this, just to ensure that users remain thoroughly confused. One thing that’s consistent is that on any...