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

File transfer security – FTP


File transfer security (FTP) has been the most common protocol for file transfers. When we talk about a file transfer protocol like FTP, it means the protocol is used to send streams of bits stored as a single unit in a particular filesystem. However, this process is not completely secure.

FTP has a lot of vulnerabilities and also it does not provide any encryption for data transfer.

Let's discuss a few security risks related to using FTP:

  • FTP bounce attack: When a file transfer happens using the FTP protocol, the source server sends the data to the client, and then the client transmits the data to the destination server. However, in the case of slow connections, users may use the FTP proxy and this makes the client transmit the data directly between the two servers.
  • In this kind of scenario, a hacker may use a PORT command to make a request to access ports by being the man-in-the-middle for that particular file transfer request. Then, the hacker can execute port...