Mastering FreeBSD and OpenBSD Security [Paperback]

O'Reilly

Mastering FreeBSD and OpenBSD Security

By Yanek Korff, Paco Hope, Bruce Potter

First Edition March 2005

ISBN: 0-596-00626-8

464 pages, $49.95 US

http://www.oreilly.com/catalog/mfreeopenbsd/

This book has been long awaited as the *BSD community has been lacking the number of security geared books compared to the Linux and Windows communities. I found that this book is almost the equal of "Linux Server Security", but for OpenBSD and FreeBSD. With OpenBSD being said to be one of the most secure operating systems, you would think there would be more books about the security other than the normal online documentation.

I'm glad O'Reilly finally put out this book as it covers a broad area of security within OpenBSD and FreeBSD.

This covers *BSD basics, initial install and hardening of the specific OS, security practices, running secure servers (DNS, Mail, Web), firewall, intrusion detection, system audits, incident response, and forensics. This is a broad coverage of security, but I wish on some of the specifics they would have went into detail discussing.

Some points I wish were added in detail was coverage on OpenNTPD's security and/or atleast mentioning that it is contained within OpenBSD. Another would be more coverage of Qmail on FreeBSD/OpenBSD as there really wasn't much more than a mention of Qmail and basic information. Compared to the details given to Sendmail and Postfix, Qmail info was really slacking. The last point I would like to mention that I found lacking was possibly a more in-depth guide to CARP and what it's capable of doing. The main thing dealing with CARP that I would have liked to see would be about load balancing firewalls using CARP and PFSYNC.

Other than these few minor lacking areas, I found this book to be great addition to other security books based around general Linux and BSD servers. I almost wish this book would have waited a little while longer before releasing or hope they plan an update soon as OpenBSD 3.7 is scheduled for release on May 19th and this book mainly just covers versions 3.5/3.6 for OpenBSD. Along with the new version of OpenBSD releasing, FreeBSD 5.4 was released not long after this book was published.

Even lacking the parts that it does, I enjoyed reading the sections about DJBDNS comparison to BIND with details of the specifics. On top of this, there is enough information to get anyone with general *nix knowledge going with a OpenBSD/FreeBSD firewall or secure server. By no means is this book the answer to first time OpenBSD/FreeBSD system administrators to learn the basics from, but seems to be more geared for those atleast somewhat familiar with the *BSD feel of things and aware of what's going on inside their machine. In the beginning of the book it mentions this book was written "by system administrators for system administrators". For someone just getting started with OpenBSD I'd recommend this book, but also would recommend picking up Absolute OpenBSD (http://www.oreilly.com/catalog/1886411999/) for more coverage of the basics. Otherwise, it will be difficult picking up on what they are saying in this book. Also, on the FreeBSD side of things I'd recommend Absolute BSD (http://www.oreilly.com/catalog/1886411743/index.html) or The Complete FreeBSD (http://www.oreilly.com/catalog/cfreebsd/index.html). If your new to *BSD this book will help but a book to compliment it will help even more. Atleast once you learn the basics, you will get a detailed bit of information on securing your new *BSD box.

I believe the writers met their goal of creating a book to solely cover the security features of OpenBSD and FreeBSD aswell as the types of servers run on those platforms. I'm glad this book arrived and look forward to seeing if they release a 2nd edition that is updated and possibly covers the parts that seem to be missing or lacking in detail. Congrats to O'Reilly and the writers.

Lloyd Randall

Pensacola Linux User's Group

Mastering FreeBSD and OpenBSD Security (MFAOS) more or less delivers on its subtitle: "Building, securing, and maintaining BSD systems." The book is chock full of absolutely sound administration advice from three experts with plenty of operational experience. I am also thrilled whenever I find a new BSD title on bookshelves. However, I believe a second edition of this book should be radically altered to better deliver value to the reader.

Note: I am in a somewhat awkward position as I write this review, since I know one of the authors as a fellow local security professional. I've spoken at a conference he organizes and I even have all three authors' signatures on my copy of MFAOS! Still, I hope they will consider incorporating my ideas when O'Reilly asks for a second edition.

First, I think MFAOS:2E should address FreeBSD, OpenBSD, and NetBSD. It's appropriate to read a book only about ONE of the BSDs, or all three of the BSDs. It's odd to cover FreeBSD and OpenBSD but not NetBSD. I think DragonFly BSD's miniscule userbase puts it on the fringe, and Mac OS X is not BSD.

Second, the authors should rigorously concentrate on covering BSD-specific administration and security issues. I do not need to read about generic security issues in Ch 1, or standard DNS/Mail/Web attacks in Chs 5/6/7. I definitely did not need YASD (Yet Another Snort Doc) in Ch 9 -- especially when ACID is explained as the console of choice. (BASE replaced ACID in Sep 04). I do not need the advice on incident response and forensics found in Ch 11. MFAOS should be a more of a BSD book and less of a security book.

Removing all of this generic material in a second edition would provide room to focus on BSD-specific material not found elsewhere. For example, Dru Lavigne's briefer, older, all-BSD book BSD Hacks gives more information on FreeBSD's Mandatory Access Controls than MFAOS -- and MFAOS is a BSD security book. I would have liked more details on building FreeBSD jails, especially with respect to creating a local package builder.

While reading MFAOS, I frequently felt the authors did not provide enough details on the subjects I felt were different from multi-platform Unix books. For example, why write five pages on Nagios in Ch 4 if that information really isn't enough to do anything useful?

It seemed the authors assumed many of their brief discussions of useful behavior was sufficient for the reader. In reality, I probably wouldn't be reading the book if I could get by on the information provided; I'd be implementing on my own. For example, the authors devote 3 1/2 pages in Ch 4 to using CVS to track changes to configuration files. While not BSD-specific, this is the sort of good practice not frequently covered elsewhere. Yet, when I hoped for more advanced discussions I see the phrase "beyond the scope of this book" on p 136.

I was disappointed that Qmail was ignored in Ch 6, even though Djbdns was addressed in Ch 5. Furthermore, when the authors repeatedly admit that Dan Berstein's software isn't well documented, they should recognize that as an opportunity! Say less on Apache, BIND, etc., and cover the lesser-known but potentially more secure alternatives.

I rate this book highly (four stars) because it's full of good advice. For example, I liked recommendations on using flags, secure levels, and similar topics in Ch 2. I liked the two-tiered Web server architecture in Ch 7, as well as comparisons of IPFW and Pf in Ch 8. You won't find me disagreeing with the authors of this book -- except when they configure Snort to log directly to a database. (Ouch -- that has been bad advice since Barnyard was released in Dec 02.)

A second edition should also keep in mind the binary upgrade and patching tools available since FreeBSD 5.x -- updating via source isn't necessary for many admins these days. Also, if they insist on demonstrating how to set up well-documented servers (DNS/Web/Mail), try picking one app and one BSD. Then thoroughly document setting up the entire system, from install to deployment. Consider providing templates, especially for automated and repeatable installations. Tie them to standards like CISecurity if possible. That would be exceptional.

I wish the authors had directed their talents toward BSD-specific quirks and less on topics covered elsewhere. This is still a solid BSD book, but I would be very glad to see MFAOS:2E take this advice to heart.

I was really hoping to see a chapter on systrace or other advanced host-based security tools (HIPS and other kernel utils). All in all, the book is a nice addition to any security library. The basic ideas of risk management and confidentiality, integrity and availability (CIA), are covered throughout the book. I would say this is a good reference to use in addition to the man pages for both operating systems.