Book Image

Practical Linux Security Cookbook - Second Edition

By : Tajinder Kalsi
Book Image

Practical Linux Security Cookbook - Second Edition

By: Tajinder Kalsi

Overview of this book

Over the last few years, system security has gained a lot of momentum and software professionals are focusing heavily on it. Linux is often treated as a highly secure operating system. However, the reality is that Linux has its share of security ?aws, and these security ?aws allow attackers to get into your system and modify or even destroy your important data. But there’s no need to panic, since there are various mechanisms by which these ?aws can be removed, and this book will help you learn about different types of Linux security to create a more secure Linux system. With a step-by-step recipe approach, the book starts by introducing you to various threats to Linux systems. Then, this book will walk you through customizing the Linux kernel and securing local files. Next, you will move on to managing user authentication both locally and remotely and mitigating network attacks. Later, you will learn about application security and kernel vulnerabilities. You will also learn about patching Bash vulnerability, packet filtering, handling incidents, and monitoring system logs. Finally, you will learn about auditing using system services and performing vulnerability scanning on Linux. By the end of this book, you will be able to secure your Linux systems and create a robust environment.
Table of Contents (20 chapters)
Title Page
Copyright and Credits
Contributors
Packt Upsell
Preface
Index

Kernel errors


Kernel panic or kernel error is a term used when a Linux system has come to halt and seems unresponsive. When the kernel detects an abnormal situation, it voluntarily halts the system activity. When the Linux system detects an internal fatal error from which it cannot recover safely, it generates a kernel panic.

Causes of kernel errors

In Linux, a kernel error can be caused due to various reasons. Here we will discuss a few of the reasons:

  • Hardware – Machine Check Exceptions: This type of kernel error is caused when a component failure is detected and reported by the hardware through an exception. This typically looks like this:
System hangs or kernel panics with MCE (Machine Check Exception) in /var/log/messages file.
System was not responding. Checked the messages in netdump server. Found the following messages ..."Kernel panic - not syncing: Machine check".
System crashes under load.
System crashed and rebooted.
Machine Check Exception panic
  • Error Detection and Correction (EDAC...