Linux Security Cookbook

The "Linux Security Cookbook" includes real solutions to a wide range of targeted problems, such as sending encrypted email within Emacs, restricting access to network services at particular times of day, firewalling a webserver, preventing IP spoofing, setting up key-based SSH authentication, and much more. With over 150 ready-to-use scripts and configuration files, this unique book helps administrators secure their systems without having to look up specific syntax. The book begins with recipes devised to establish a secure system, then moves on to secure day-to-day practices, and concludes with techniques to help your system stay secure.

Some of the "recipes" you'll find in this book are:

Controlling access to your system from firewalls down to individual services, using iptables, ipchains, xinetd, inetd, and more

Monitoring your network with tcpdump, dsniff, netstat, and other tools

Protecting network connections with Secure Shell (SSH) and stunnel

Safeguarding email sessions with Secure Sockets Layer (SSL)

Encrypting files and email messages with GnuPG

Probing your own security with password crackers, nmap, and handy scripts

This cookbook's proven techniques are derived from hard-won experience. Whether you're responsible for security on a home Linux system or for a large corporation, or somewhere in between, you'll find valuable, to-the-point, practical recipes for dealing with everyday security issues. This book is a system saver.

The recipes in this book allows administrators to learn quick and easy ways to secure their systems including over 150 ready-to-use scripts and configuration files without having to look up or research specific syntax.

This book is definitely a quick hands-on guide to securing and monitoring your system and would recommend it to anyone looking for a good source of guides and ready-to-use scripts and configurations.


Excellent resource on Linux security   December 9, 2003
 14 out of 14 found this review helpful

At fewer than 300 pages, the initial size of the Linux Security Cookbook may seem to be meager to cover such a broad subject. But what the book lacks in size, it makes up in content.

While many security books may waste the reader's time by spending hundreds of pages on introductory subjects; chapter 1 of the Linux Security Cookbook goes straight into using and configuring Tripwire.

The book then goes into fundamental topics such as firewalling with iptables/ipchains, authentication, access control, file control, email security and more.

If you are interested in Linux security, this is a well-written and well-organized book, filled with valuable and timely information.


Good book for quick reference...   August 29, 2003
 19 out of 20 found this review helpful

I read this book from cover to cover and consider it a great effort by the authors to cover many security issues related to not just Linux, but most *nix operating systems. Here's a chapter by chapter review of what I've observed in the book:

Chapter 1 - System Snapshots with Tripwire

I liked the discussion of Tripwire and its configuration options. The sections on "Ultra-Paranoid Integrity Checking" were great! A decent introduction to Tripwire and some of its features.

Chapter 2 - Firewalls with iptables and ipchains

The difference between "Drop versus Reject" targets was good. So many books have info on iptables, but none discusses these issues. Also the point made about dropping ICMP messages was good. Quick to learn and implement recipes presented in this chapter.

Chapter 3 - Restricting Access by Remote Users

Recipe 3.7 was very neat. Allowing users to access a service only by port-forwarding over ssh allows the administrator to restrict access by user names. A smart way of imposing restrictions!
Also, in recipe 3.9, I liked the authors' approach to finding if xinetd is compiled with libwrap support.

All recipes regarding tweaking xinetd were good. It isn't always possible to look at all the configurable options with xinetd, and the authors did a good job in mentioning a few useful options.

Chapter 4 - Authentication Techniques and Infrastructures

Quick tips with PAM, openssl and kerberos. I couldnt get some of the recipes to work on my machine, but got most openssl stuff to work.

Chapter 5 - Authorization Controls

I liked this chapter the best. The discussion on sudo was enlightening, and I was able to effectively tweak most recipes to my needs. The man page would never have provided me with such a good explanation. Thanks to the authors for this chapter.

Chapter 6 - Protecting Outgoing Network Connections

Two of these authors had written the snail book and I expected nothing less than a very useful recipe session on SSH. The most useful recipe here was setting up public key authentication between an openssh client and an ssh.com server and vice-versa. I had always wanted to do this but didnt have a clue until I read these recipes. All recipes have strong technical content and are well written. The recipe on running cron jobs with ssh was
amazing. The authors teach how to be creative, rather than merely
explaining facts and methodologies.

Chapter 7 - Protecting Files

I liked all recipes on GnuPG especially neat hacks like maintaining encrypted files with vim, encrypting backups etc..

Chapter 8 - Protecting Email

I tried out a few recipes and got them to work with my configuration. Pretty impressive stuff! The difference between SSL and STARTTLS daemons was very well explained. I havent seen a consolidated discussion on this topic thus far and was really happy to see things explained clearly in just one sidebar. I couldn't get the imap/ssl recipe working for my settings, inspite of spending quite some time. Perhaps a few screen-shots
made available via the website would've been of greatest help..

Chapter 9 - Testing and Monitoring

Recipes on Cracklib, using find for setuid/setgid files and the discussion on the 'find' command are very well written. Though this stuff has been mentioned in most security books/magazines, a consolidated treatment here is nice to note. nmap truly deserved the long section and I was able to learn a few facts I didnt know about nmap until now. The recipe on examining local network activities covered the best tools in business -
netstat, lsof and rpcinfo. Sniffing network traffic, using tcpdump, ethereal and dsniff provide a good refresher and ready-to-use recipes.

Overall, Linux Security Cookbook is a very useful book for quick
reference. It covers a wide range of security topics and issues related to not just Linux but most Unices. The recipes provided here are well written and ready to use. I have found many tips related to sudo, SSH, xinetd, encryption and network security extremely useful. Full credit to the authors for bringing out such a comprehensive book on Linux Security.


Not up to par   July 29, 2003
 4 out of 19 found this review helpful

I've been reading "Linux Security Cookbook". I fully understand the goal of this book is to provide lots of little bits of wisdom, not a full fledged security book. I think that's pretty cool. However I'm finding that a lot of the recipies, if you will, are either not well explained, the equivalent of reading a real cookbook witohut knowing what it means ot 'fold the blueberries into the batter'. They could easily have spent more time explaining things so we didn't need to go read/re-reading the man pages just to understand the book.



Worth it   July 28, 2003
A very cool collection of recipes for common, daily, security of Linux
systems. Some of the other reviewers missed the point...this book
doesn't try to be the ultimate self-contained security book, it's a
collection of one-off recipes...it even says so on page 1. Look at
O'Reilly's other cookbooks (the awesome Perl Cookbook, Javascript
Cookbook, etc)--they aren't meant to be comprehensive or teach you
everything about the subject, they assume you know the basics already
and show you specific solutions to specific problems. This cookbook
does the same thing with Linux security, and I think it succeeds...it
sure helped me with my firewall and with gpg encryption. This
shouldn't be the only security book you own but it's great for what it
is.