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

Detecting compromised passwords

Yes, dear hearts, the bad guys do have extensive dictionaries of passwords that either are commonly used or have been compromised. One of the most effective ways of brute-forcing passwords is to use these dictionaries to perform a dictionary attack. This is when the password-cracking tool reads in passwords from a specified dictionary and tries each one until either the list has been exhausted, or until the attack is successful. So, how do you know if your password is on one of those lists? Easy. Just use one of the online services that will check your password for you. One popular site is Have I Been Pwned?, which you can see here:

You can get to Have I Been Pwned? here:

https://haveibeenpwned.com

All you really have to do is to type in your password, and the service will show if it's on any lists of compromised passwords. But think about...