Hacking Linux Exposed





Many online booksellers include the ability for customers to submit reviews. We currently watch for entries on Amazon, Barnes and Noble and Bookpool.

We include every review that we find here, even those with which we don't agree, without modification. (Well, we enforce a consistant format, but that's it.) The reviews here were last updated 31-Mar-2003. If you see a review that isn't here and we don't catch it in a few days, slap bri@hackinglinuxexposed.com upside the head with a quick email.

Amazon Reviews

(Includes amazon.co.uk)

5 Stars Don't have this book? You're BEGGING for trouble..., 30-Apr-2003
When I first starting using Linux systems and putting them online I had NO idea what sort of grief I was in for. The reason for that grief: I had NO clue how to 'harden' a system or what that term even meant. By not knowing that I put up systems that were quickly exploited by script kiddies and SPAM houses looking for open relays to use for SPAM and for 'zombies' to use in Distributed Denial of Service (DDoS) attacks. I bought this book, read it, and haven't had those problems since. If you are going to do *anything* with Linux on the internet then GET THIS BOOK NOW. Unless, of course, you *want* to have your computers destroyed on a weekly basis...
A reader, Bonney Lake, WA USA.

5 Stars The best hands-on Linux security book just got better, 10-Mar-2003
I'm a big fan of the Hacking Exposed style of writing. All offensive theory is backed up by command line examples, followed by defensive countermeasures. Hacking Exposed: Linux, 2nd Ed (HE:L2E) follows this tradition, updating the content of the first edition and adding 200 pages of new content. Although I reviewed the first edition in Sep 01, reading the second edition reminded me of the challenges posed by securely configuring and deploying Linux systems.

The best way to learn while reading HE:L2E is to try the sample commands. I also recommend visiting the links mentioned and installing many of the tools described by the authors. I found programs like raccess, nsat (ch. 3), sslsniff (ch. 7), nstx, and httptunnel (ch. 15) particularly interesting from an attacker's point of view. From a system administration standpoint, coverage of passlogd (ch. 2), lilo and grub (ch. 5), and X (ch. 6) were very helpful.

The authors share many novel ways to abuse Linux systems, but counter those exploits with little-known features or third-party tools. I never knew I could use bash's HISTCONTROL feature to selectively remove entries from shell history files. HE:L2E goes the extra mile to help secure your system, such as including sample C code in ch. 13 to allow one to compile TCP Wrappers support into one's own programs. Other clear, concise defensive measures were introduced in excellent chapters on keeping the kernel and packages current (appendix B) and pro- active security measures (ch. 2). The last appendix gives a short yet powerful description of the damage an intruder can perform, showing how he hid unauthorized programs and how those programs were discovered.

If you use Linux, you'll find HE:L2E indispensable. I even applied many of the tools and techniques to my FreeBSD system, showing that that good security advice can be a cross-platform endeavor.
Richard Bejtlich, Washington, DC.

5 Stars Second edition is great!, 10-Mar-2003
Just got second edition, can't put it down. Huge number of changes, all of them good. More backdoors, more network hacks, more sample code, more depth. Didn't think the first one could get better, I was very wrong.
jbw626, Bristol.

5 Stars The best Linux Security book on the market, 07-Mar-2003
Hacking Linux Exposed proves itself the leader again in this, the Second Edition. The authors go into great depth showing you every nuance of Linux from a security standpoint, showing you the potential chinks in the armor and the locks wait ing to be picked. You get an excellent view of exactly how an attacker can get into your computer, and at each step you learn the configuration changes you can make to keep them out. I don't think there's a better way to explain the dangers than by watching how the attacks work, and this book sets the standard. I find the appendicies to be extreemly valuable, because they detail how to recover a compromised system, how to keep your software up to date, even how to patch and recompile your kernel with the exact same functionality of the one you're running, to avoid configuration changes, crashes, or other suprising results. No Linux administrator can survive without a copy of Hacking Linux Exposed, Second Edition on their bookshelf.
jjtus, Rome, Italy.

5 Stars Useful and fun to read, 11-Jan-2003
"Hacking Linux Exposed", 2nd edition does what few books do - it exceeds its first edition in both the extent of coverage and presentation style. Note that the first book was already a great resource.

The book now appeals not only to Linux beginners, but for more advanced users and developers as well. It provides wonderfully detailed and correct technical descriptions, gives sounds and simple-to-use advice and entertains with great writing style and authors' sense of humor. The content of the book is also very current (late 2002). It shines brilliantly on the background of vaporous and unoriginal security books published today.

Wireless, physical attacks and social engineering are woven into the fabric of Linux security. There are fun descriptions for classic attacks, which provide worthwhile reading even for people who already know them. Attacks against network clients sections is especially interesting as those attacks were used in some recent high -profile penetrations.

Kernel security (including capabilities) gets the coverage it deserves. An entire loadable kernel module (LKM) code is included. Several common malicious LKMs are analyzed in the book. In addition, the authors show how attackers can easily modify the Linux kernel itself to hide programs and get extra privileges.

A nice summary of attack methods against many network protocols is very useful as a reference. For example, many attacks against FTP are described analyzed and practical protection techniques are outlined. Description of security of various mail servers is detailed and comprehensive. I also liked the well-supported argument of DJBDNS vs BIND.

An overview of classic backdoor methods is similarly useful. Crontab backdoors, .forward abuse and other techniques are all in the book. Also, a well-written overview of CGI abuses that delves into the realm of security programming is provided.

Another advantage is that authors uncovered many great little known security tools for Linux and provided useful descriptions for their use. Overall, tool descriptions are kept to a reasonable size, add value to the tool included documentation and give pointers to learn more by using them.

Book appendices contain a fun case study, and a great section on "Discovering and Recovering from Attacks". Be sure to read the appendix and keep the book handy as a reference.

Overall, the book is necessary tool for security professionals and others dealing with Linux security. I suspect that even the most advanced Linux security experts will pick up a thing or two from the book. The book's information delivery is flawless.

Anton Chuvakin, Ph.D., GCIA is a Senior Security Analyst with a major information security company. His areas of infosec expertise include intrusion detection, UNIX security, forensics, honeypots, etc. In his spare time, he maintains his security portal info-secure.org
Anton Chuvakin, NJ, USA.

5 Stars An excellent security book, excellent Linux book, 29-Dec-2002
I am very new to Linux. I've got a lot of windows experience and an MCSE, but recently my job has included a few Linux machines when other guys were downsized. Our Linux machines are the ones on the Internet, so security is relly important. I picked this book up after looking at four or five, and am really happy with my choice.The solutions they provide are clear enough that even a guy like me who is intimidated by Bash can make them all work. The desciptions of the attacks are very complete, and I learned a lot of network attacks that would affect windows machines, but were never explained in my MCSE training -- probably because only Linux has ways to defeat them.This book taught me a lot of Linux tips along the way too. I even followed along and have compiled a Linux kernel from scratch -- something I never expected to get from a security book in such easy to follow instructions.I recommend this book to any Linux user, new or experienced.
Nicky Boran, Atherton, CA.

5 Stars Full Disclosure at it's best, 27-Dec-2002
If you're looking for a book that doesn't hold it's punches, this is the one. These chapters are filled with tricks that can be used for good or ill. I'd love to know the ratio of white to black hats that read this book. But, for all the ideas it may give to the bad guys, it shows exactly what you need to do to keep those bad guys out of your machine. Get it before they do.
A reader, Vienna, VA USA.

5 Stars Worth it many times over!, 27-Dec-2002
Hacking Linux comes in six parts, each of which is worth the price of the book in whole. Part one: security overview covers all the basics like file permissions, setuserid problems, buffer overflows/format string attacks, tools to use before you go online, and mapping tools like nmap. Part two comes in from more of the hacker angle with social engineering and trojans, attacks from the console, and then concludes with two excellent chapters about netowrk attacks and TCP/IP vulnerabilities.

All the stuff to this point assumes the hacker is on the outside. Part three takes over and shows you what the hacker will do once they've gotten on, such as attacking other local users including root, and cracking passwords. It becomes obvious that you need to protect things from insiders as much as from the outsider, because the outsider will usually get in as a normal user first, and if you can prevent him or her from getting root access, the damage cannot be nearly as severe. A lot of books don't cover this angle at all, and it's done superbly here.

Part four covers common problems in internet services. First they discuss mail servers. Sendmail, Qmail, Postfix, and Exim each get covered in detail - it's nice to see more than just Sendmail discussed in a security book. Of course, it'd be even nicer to see something other than Sendmail installed on a Linux machine by default. Next they cover problems with FTP software and problems with the FTP protocol. I'd never seen "beneath the hood" and realized how wierd FTP really was, and why it's not supported by firewalls very well, and the authors show you the inner workings of it so anyone can understand the problems. They continue with Apache and CGI/mod_perl/PHP/etc problems, both from a coding standpoint and how to secure against outsiders and your own web developers. Next it's on to Firewalls (iptables and TCP wrappers) and lastly (distributed) denial of service attacks. The countermeasures for the DOS problems are excellent, and a must for anyone with a server.

Part five covers everything a hacker can do once they've broken in. They describe trojan programs, trojan kernel modules, and configuration changes that can be used to keep root access, or hide the hacker activity, or let them get back in should the computer be partially fixed. This was not only complete, but scary in how many different things they showed. It works both as a blueprint for what you need to defend against, how to clean up after a hacker has gotten in, and also how you could back door a machine if you get in. I'll leave the ethics up to you.

Lastly we have part six, which is the appendicies. While most times I ignore appendicies, these are really an integral part of the book, and are referenced throughout the book all over. (This very good, because it keeps the book from having too much repeated countermeasures.) They discuss post-breakin cleanup, updating your software and kernel, and turning off daemons (both local and network ones) and a new case study. The book is good about covering Linux from a distribution-agnostic standpoint (it doesn't assume you use RedHat, unlike everything else out there) but in these appendicies they cover the differences you may encounter. They show you how to use dpkg/apt-get as much as RPM as much as .tgz packages, discuss both inetd and xinetd, and even svscan/supervise. They are extreemly complete.

Hacking Linux Exposed 2nd Edition is required reading for anyone with a Linux machine, period.
Trin, Lafayette, Louisiana.

5 Stars Rocks!!!, 26-Dec-2002
Man, this book is great! I've learned tons of tricks in the last five days with this book. This has so many examples and tools that you can really learn the hacker's secrets.
sbond, KY, USA.

5 Stars Wish I'd had this a few weeks earlier., 25-Dec-2002
My partner told me that I was to buy no computer books until after christmas because I'd be getting some under the tree. Well, we opened presents on the 24th this year, and I've been unable to put this book down since I opened it.

This book takes a very good look at all aspects of computer security from the Linux perspective. I was able to get several of the "Proactive Security" stuff from chapter 2 installed on my machine this afternoon, and was shocked to see how much my machine (we're on a cable modem) was being probed from all over. Looking at some of the traffic using the sniffers they describe, I could see some wierd stuff coming *FROM* my computer that wasn't caused by me.

I haven't gotten far in the book yet, but I've pulled it off the Internet until I have a chance to read the rest and can get these hackers off my machine. I've jumped up to part 3 of the book, where they have three whole chapters about what the bad guys do once they get on, and I've plugged five holes already. I have no idea how long I've been hacked, but by the time I'm done reading this book and using what they say, I can feel safe that I won't be such an easy target.
Brett Noble, Orange, CT.

5 Stars This helped me clean up my machine, 25-Dec-2002
I started reading this as soon as i got it. The first chapter tells you why a hacker might want your machine even if it dosn't have anything interesting on it. They explained how you might notice that you've been hacked, and the things they said were just what was happening on my machine!I'd suspected that someone had broken in, but this book showed me exactly what I needed to do to kick the hacker off and take back my machine.So for me, the real world value of this book is immeasureable.
tessm, Baltimore.

5 Stars The best of the bunch, 21-Dec-2002
My hubby got me 5 linux security books for christmas, and beeing the sweetie he is he let me have them early. I scanned through all of them quickly to pick which one was best to start with, and Hacking Linux Exposed won. Of all the books, this one had the most digestable format - each chapter is very standalone with well defined parts, but somehow it all manages to build on the stuff before. So you can read it without dedicating several hours each time -- you can very easily read a section between tasks at work, and soon you've read the whole thing. (Although last night I read through almost half of it again before going to bed, a failing of mine, and a complement to the book.)

This book has the most complete instructions and examples of the books I got. I've started reading the others now, but keep thinking that 'hacking' did it better.
Jodi S, Alameda, CA.

5 Stars Editoral Reviews, 10-Dec-2002
"Throw up a Linux box," comes the chorus whenever there's a need to provide some network service or other without impinging upon the boss's martini budget. Fair enough, but by doing so are you opening security holes you don't know how to find or fix? The newest edition of Hacking Linux Exposed helps you answer that question and solve many of the security problems you find. To a certain extent this book is a recipe collection in that it describes weaknesses in Linux (calling attention to specific distributions where appropriate). The authors stop short of explicitly showing you how to wage most kinds of attacks, a reasonable thing to do from an ethical point of view even though the instructions can be found easily on the Internet. Rather than do that, they give step-by-step instructions on how to defend against the attacks they catalog. The point is not, "Here's precisely how to bring down a server by means of an ACK storm," but rather, "Here's how to defend against such problems." They do demonstrate plenty of weaknesses, though, as in their coverage of the conversation that goes back and forth between an FTP server and its client.

This book covers pretty much everything you'd want to do with a Linux machine as a network server. Read it and see some of the weaknesses in your system--and do something about them before someone else does.
David Wall.

Barnes & Noble

5 Stars Second Edition Rocks!, 23-Dec-2002
I got the new version of Hacking Linux Exposed yesterday and read it straight through. I've been using the first edition since I bought it last year, but this one really blows the first one out of the water. It has a ton of new information - I particularly liked the stuff about wireless attacks and how to create a secure wireless network using VPNs so you don't need to rely on the wireless protocols that don't work correctly. Also the info about web hacks helped me find MANY bugs in our company's website that could have been used against us -- now we've got to see if we've been hacked before and start cleaning up.

Also recommended: Hacking Linux Exposed, 1st edition.
Juan Rodriguez, a webmaster and linux guru.


5 Stars Second edition far better than the first, 23-Dec-2002
The first edition of hacking linux exposed was groundbreaking - finally you got to see under the hood exactly what the hackers could do to you, and what you needed to do to keep them out. In the second edition they've added tons of new material and examples. You can easily spend a month reading this non-stop and trying out everything for yourself. A must-have security resource.
Ted Lewis from New Mexico.

Customer Reviews for Hacking Linux Exposed, First Edition.

We've done our best to preserve everything that was good from the first edition, so these reviews of the original are still relevant. Of course, you're welcome to purchase the original if you wish, for that matter.

Amazon Reviews

(Includes amazon.co.uk)

Great book., 7-Mar-2003
I just finished going through the entire book line by line. I am extreemly new to Linux and security, and this book made it all very clear. I only wish I realized that there was a second edition out when I bought this one. Everything in this original edition was still completely correct and appropriate, three years later.
Edward Kakani, Howell, NJ USA.

Refreshingly honest, thoroughly enlightening, 06-Mar-2003
Given the complexity of Linux systems, and the years spent hardening such systems against would-be intruders, it is amazing how a simple, clever idea can still translate into a full-blown security exploit.

I really enjoyed the format of the book. The authors don't waste time on security theories, or explaining what Linux is. They know the reader is already familiar with these, and wants to know, in concrete terms, how a hacker sees your server, and will systematically breach its security until they get root access. The authors waste no time in revealing the tools of the trade, and the security-conscious would do well to read this book from cover to cover. It is not enough to just apply patches, and turn off unnecessary services (and surprisingly few admins even do this right). One must fully understand the mindset of the hacker, and see the server from the outside.

I truly believe that no other book right now can deliver such honesty and such useful information on Linux security. If you hope to secure your servers or go into the security field, definitely read this book. You will not be sorry. :)
pho_kin, Seattle, USA.

5 Stars Frequent Reference, 21-Dec-2002
I've had this book since early 2001, and use it at least once a week. I use it for both security information, as well as a reference for good programming style and tricks. I really want to buy the second edition, but don't have the cash right now. But I can promise that this first edition is still completely useful today as the day it was released.
Cathi Balsinger, Austin, TX.

5 Stars Just a must have, 04-Dec-2002
It covers most important topic these days. Excellent examples/cases, software recommendaitions, solutions.... I do higly recommned this book.
Luis Carlos Solano, San Jose, Costa Rica.

5 Stars Good intro to Linux security, 17-May-2002
Hacking Linux Exposed by Bri Hatch, James Lee and George Kurtz, is a nice follow-up to their bestselling Hacking Exposed . While not as groundshaking as its predecessor, the new book does provide a good reference for people just starting with Linux. Anyone who is setting up or planning to set up a Linux network should consider owning it, together with the appropriate Linux administration manuals.

Hacking Linux Exposed covers security administration issues such as FTP, sendmail (but for some reason, not POP3/IMAP servers) and web server setup; it also discusses local user security issues and touches lightly on Linux firewalling and other network access controls (TCP wrappers).

The book includes a big section on keeping your system updated, which outlines methods used by several popular Linux distributions (rpm from RedHat, apt-get from Debian and pkgtool from Slackware). This information is essential to the security of any Linux machine, whether a home workstation or company server.

The focus is Linux, but the book also covers some other important security areas. It attempts to offer a total solution for Linux security, starting with general infosec philosophy (such as proactive security), and moving on to physical security, social engineering, Trojan programs, access control, user security and server setup. Each security problem is rated for global risk on a 1 to 10 scale, factoring in frequency, simplicity and impact. In general, the book is more encyclopedia than detailed guide, as it strives toward breadth over depth.
Anton Chuvakin, NJ, USA.

5 Stars Learning? You need this one., 30-Nov-2001
If you are new to Linux or responsible for Linux infrastructure security this book is for you. Good detail and really essential detail that you can't pick up in your Linux how to and installation books.
i8abvr, West Hartford, CT United States.

5 Stars Excellence through examples, 25-Sep-2001
I am a senior engineer for network security operations. I read "Hacking Linux Exposed" (HLE) to learn how adversaries compromise Linux hosts. HLE impressed me at every level. I highly recommend system administrators and security personnel read and heed this book's recommendations.

The "Hacking Exposed" series is known for its unique example-driven style. Rather than telling the reader about a technique or problem, the authors demonstrate the issue using command-line examples. I find myself reading with book and laptop at hand, ready to duplicate the authors' sample commands. This process reinforces the authors' message, while the reader learns if a specific problem applies to his situation. Furthermore, by showing exactly how to execute certain commands, the authors impart bits of wisdom and trickery not found elsewhere.

For example, chapter 11 describes attacks and defenses for FTP servers. To explain active and passive FTP sessions, the authors demonstrate running an FTP client with the -d switch to illustrate raw instructions sent by the client over the FTP command channel. I had never seen this switch in use, but as an intrusion detector I constantly see raw FTP instructions like those revealed by the -d switch. These and other tidbits, like using the chattr -i command or setting the "sticky bit", make HLE exceptional.

Beyond these benefits, readers will enjoy clear, thorough explanations of Linux security issues. HLE gives first-rate descriptions of ssh and web man-in-the-middle attacks, race conditions, and FTP data hijacking. HLE also provides great illustrated examples of FTP bounce attacks, giving intrusion detectors the minutiae we need to recognize these techniques. I had heard of most of the compromise methods offered by HLE, but never seen them discussed in such practical detail.

If the material in chapters 1-13 of HLE don't prompt you to verify your Linux host's integrity, then the case studies in appendix D will. The security community needs more of these narratives. These stories, based on true events, show the lengths to which some attacks will go to penetrate target machines.

"Hacking Linux Exposed" is another strong addition to the "Hacking Exposed" series, and the security community will benefit as a result.

(Disclaimer: I received a free review copy from the publisher.)

Richard Bejtlich, Texas, USA.

5 Stars Truly superb, 23-Sep-2001
I read a review of this book on slashdot and went out to the bookstore that day to check it out. I was planning on skimming through at the store to make sure it was worth buying, but ended up reading four chapters on the floor in the isle because I was unable to tear myself away. Needless to say, I bought a copy. Although I thought I'd done a good job securing my machines, I find that I had a number of things still left open and potentially vulnerable. I'm now working through the book chapter by chapter while I sit at my Linux machine fixing things. I highly recommend this book, especially to folks like me who think they have already done a good job protecting their machines to make sure you haven't missed anything.
Peter Walmsley, Marietta, GA.

5 Stars Excellent, 17-Sep-2001
A good book for the newbie (like me)and the expert alike. Alot of people could save alot of time and alot of sleepless nights, not to mention alot of frantic email to security mailing lists, by reading this book. IMHO without a doubt the most readable and enjoyable tech oriented manual I have ever read. Worth every penny.
Christopher Muns, kennewick, WA. United States.

5 Stars great book, 6-Sep-2001
Hacking Linux Exposed is excellent. It really shows you what you need to do to keep others off of your machine. It really hit the ground running, unlike Hacking Exposed which needed to wait until the second edition to be really good.
Sam Frakes, West Virginia.

5 Stars Hacker's Guide, 31-Aug-2001
If you're looking to learn linux hacking, this is the book for you. i learned a ton, and i thought i already knew everything. ive broken into about a hundred machines before, mostly script-kiddie style, but now i have alot more information at my fingertips and am coding my own exploits. want t learn to hack? this is the book for you.
A reader, New York, NY USA.

4 Stars Recommended for *NIX too, 29-Aug-2001
I bought this book after reading the 2nd ed. of Hacking Exposed. I wanted to learn more about security and hack attacks/exploits in the Unix environment (the original HckngXpsd has about 100 pages on Unix). I run Linux at home, and I support Solaris at work. This book while geared more towards Linux, is a very good source for general Unix security and hacks. I'd love to see one specifically for Solaris (more CDE and X stuff) but for now I can say that I've learned quite a bit from this version of the book. The one thing I wish this book included (which the original does) is real life example or stories of how an exploit was created.
Thomas Needham, Brighton, Ma USA.

5 Stars Hands down one of the best technology books I have ever read, 27-Aug-2001
I bought this book after my site got hacked. I was looking for information that I could use to protect myself, and this book delivered the goods in a huge way. I've probably read 60 or 70 technical manuals over the years and am a former DBA and sysadmin, and very few have affected me as profoundly as this one did. If you have an e-commerce site or are responsible for maintaining Linux systems, you will never view your system the same way again after reading this book - I started to read this book and whenever I saw something that I could apply to my system to make it more secure, I wrote it down on an 8.5 x 11 pad... When I'd gotten 3/4 of the way down the sheet I stopped taking notes, because I realized that I was writing something down every two pages! Another reason why this book is so useful is because IT TELLS YOU HOW TO PROTECT YOURSELF. The authors are not lightweights and give specific instructions for defending against every attack they describe. Often they make multiple suggestions, indicating when different approaches would be preferable. Despite the high level of detail, the book is well-organized, well-indexed, and surprisingly well written. Even if you think you know net security well, I would recommend checking this book out because it is so well written and easy to understand that even a script- kiddie hacker wannabe could use it to root your box...
A reader, United States.

Warning: Fake Review (Click here)
5 Stars Hacking Linux, 27-Aug-2001
Although I have only a few Linux stations to worry about, this book helps me sleep at night. For great security coverage of this hot operating system, this book is a good addition to your collection.
Steven M. James, Illinois.

5 Stars Looking for a technical book? Pick this, 19-Aug-2001
This is a book that I always been searching for. A good technical book. Before this, there is always books telling theories and all of that non techie things. But as as administrators/engineers/professionals, WE do don't that. A good book to learn,understand,planning,deploy and managing Linux in the network.
krizal, Kuala Lumpur Malaysia.

5 Stars A Must for nix Admin or User, 14-Aug-2001
I haven't finished the book right now but keep reading it. It is the best computer book I have ever read. Plain text keep user to understand more easily. The topic is well organized that you will really want to read the next chapter after you have finished one. Since it is interesting if you like security.

The stuff covered maybe not enough, but it give much of the reference that you can find it on the web. Also, I think the level is very suitable for experienced nix user or admin who want to know security about their OS.

If you want to learn how to secure your nix system, read this!!
alvinlaw, Hong Kong.

5 Stars Solid book, 13-Aug-2001
Any of the books in the Hacking Exposed Series are worth buying, and this book is no exception. I am a newbie who is just curious about hacking and computing in general. I am halfway finished with this book and I am already planning on reading this book again. Once just to get an idea of what is going on, and the second time more of as a reference. What makes this book so much better than many other computer books is that this book is a dynamic reading. By that I mean, it is not a book that will go out of date. The book gives you a firm idea of the fundamentals of Linux security, and yet provides tools and insites for the Linux guru. Linux people pride themselves on their knowledge of their OS and this book plays a fundamental role in fostering this image.
nelsonhans, Madison, Wisconsin United States.

5 Stars Saved Me, 25-Jul-2001
This book really covers everything Linux. After getting half way through the book trying to implement things they talk about I found that my machine had already been hacked. So I started with a clean install like they suggest, made changes following the methods they list, and haven't been touched since.
N. Silverman, Los Alamos, NM.

5 Stars Reads like a conversation, 16-Jul-2001
Most technical books are either detailed and unreadable, or wordy and lack depth. This book is more like a conversation between the authors and the readers. Instead of pointing at things and letting you read other people's code, it walks you through the theory and exploits, letting you try out the attack manually on your own system as you read the book.

I actually wrote Mr. Hatch about a question, and he was extreemly helpful. Through a long conversation we had, I found that the authors taught classes at Northwestern University, which is probably where their communication skills came from. Unlike many experts out there who sit in a 30 minute session with 5 minutes of questions afterwards, these guys have had to actually teach students from the ground up for an entire term. Their skill in communicating, rather than just talking, really shows in their book.

Anyway, if you want a list of attacks against Linux systems, there are many books out there you'll be fine with. However if you want a book that will truely teach you what they are, how they work, and how to defend against them, there is only one option: Hacking Linux Exposed.
Dionne Wagner, Mexico City.

5 Stars Finally, a complete reference., 13-Jul-2001
From A to Z, this book covers Linux security. It goes into more depth than any security book I've read (and that's about twenty at last count) including the biggies like Hacking Exposed itself. The authors really took the time to research the latest-greatest tools and attacks. They included a lot of the old standards, but mostly in passing, focusing on things that are still problems, not things that are old news like so many books. No Sendmail 8.8 exploits here, and good riddance.

I'd highly recommend this book for anyone who wants to see what a hacker actually does, down to the keystrokes themselves. Most importantly, you get clear easy steps to fix the problems. When there are multiple tools that you could use, they cover them in enough depth to let you know which is best for you and your skill level.

If you want to keep others off of your machine, this is the book to buy.
tedd@london.com, London, England.

5 Stars I needed this!, 12-Jul-2001
This is the book I always wanted when I would search the Internet for ways to learn how people get into computer systems and protect them. I have "Hacking Exposed" and with the migration from Windows 95 some time ago, I got this! I now enjoy using it as a very good reference and a kind of tool box. If your into Linux, you'll need this!
The price tag is good too!
Steven Simpson <scrachy@crazypenguin.co.uk>, Liverpool, England.

5 Stars Under attack!, 11-Jul-2001
I got a copy of this book three weeks ago, and have only really gone through the first two chapters -- it's that packed with information.

I have a network with several windows and linux machines, with firewall software on the PCs. According to my firewall logs, they haven't been probed more than once ever few days. Since I didn't have anything protecting my linux machines I followed some of the examples from this book and installed some scan detectors. I was seeing at least ten probes a day. I thought this was funny, since my PC firewalls weren't picking anything up, so I skipped ahead to chapter 6 where it talks about sniffing, and I can see that my PCs are in fact being targeted, but the firewalls don't log anything!

Now I'm extreemly paranoid. I've unhooked my PCs, and am going to only let the linux machines on the net -- with this book at least they can be secured for real.
hem_haw, Vancouver, Canada.

5 Stars More detailed than I'd imagined., 09-Jul-2001
I was beefing up my outdated security bookshelf, and thought I'd snag the latest in the Hacking Exposed series. I figured that since it was only covering one OS it would be able to have more depth, one of the chief failings of Hacking Exposed.

Well, I was not disapointed. This book covered aspects of Linux and network security that I had not ever thought of. It makes very appropriate use of source code to illustrate problems, and shows you the attacks in both manual and automated forms so you can actually see what's going on, rather than just saying "run the blah program" as so many other books do.

This book has information that will be useful for the newbie, but excells in including detail appropriate for all audiences. In that respect, this book almost reads like a textbook on how to hack and secure. If you're a new Linux user, you'll find good starter information, and want to come back to this periodically as you learn more. If you think you know Linux security, then this is the book against which you should test yourself. I doubt most folks have tried half the things listed in chapter 10.
herzme, St. Paul, MN.

5 Stars Should have been "Hacking Unix Exposed", 07-Jul-2001
I am in charge of network security for a large firm. We use largely FreeBSD and OpenBSD machines instead of Linux whenever possible. One of the junior folks was trying to convince us that Linux isn't all that bad, and pointed to this book as proof that it can be secured.

Well, we're not about to switch. However this book covered so many unexpected issues that affected our *BSD boxen that we spent a solid week implementing changes on all our systems. The detail of this book was superb, and it was easy to figure out the differences between their Linux-specific solutions and what was needed on our *BSD systems when they weren't exactly the same.

Got Unix? Buy this book.
the_ardvark, Chicago, IL.

4 Stars Can't put it down!!, 03-Jun-2001
The book pulls you into a hackers/crackers mind! no boring bla-bla text that puts you to sleep in 3 minutes! the only reason I gave it 4 stars is that it didn't come with a CD! Most of the books I've read came with the programs they discussed in the book, This was my only let down. I've contacted the authors about some questions and I received a fast and curtious reply. Hats off to you Gents, and I must thank Brian for his reply,about to much security, your one of the reasons I've switched from windows to linux. Try and contact Bill if ya got a question about windows!
Gavin Rollins, Fukushima, Japan.

5 Stars Buy two of these, 30-May-2001
I wasn't a fan of Hacking Exposed, largely because its Unix section was a mere 50 pages of superficial, outdated, and obvious fluff. Hacking Linux Exposed makes up for that lack by digging into Unix in much more depth. Though it is modeled after the attack/countermeasure style of the original HE, this book includes a whole chapter of security measures at the beginning that you can implement instantly to get your machine locked down before getting into the nitty-gritty detail about other things in the hacker's arsenal. I was particularly enthralled with chapter 10, which talks about what the hacker will do after they have gained root access, from simple things like adding accounts to complicated issues like kernel modules, complete with source code. Chapter 7 includes some really wonderful examples of how the hacker can abuse networking protocols themselves, something I haven't seen covered in such depth before.The book is logically organized. The first part covers the way the hackers find and probe your machine. The second talks about getting in from the outside, be it network or physical. The third part talks about gaining additional priveleges, and the last part of the book is dedicated to mail, ftp, web, and firewalls. The appendicies are actually useful. They seem to have dropped the small 1-page case studies from the original book and replaced them with longer hacker-eye-views of real attacks which are an interesting read, and really tie the book together.This book is Linux specific in it's countermeasures, but I'd recommend this to any unix user. They do a good job of discussing differences between Linux variants as well, they don't just assume everyone has a RedHat box on their desk. Very refreshing.This book is great for both the theory and practical uses. I could spend weeks implementing all the suggestions they have, but they seem to have thought of this because their risk ratings let you know where you should concentrate as you secure your systems.Like Hacking Exposed, this book also has a website, (...) but it seems more up-to-date -- for example when the ptrace bug in older kernels came out, they posted a kernel module you could compile to protect your system until you could upgrade -- and includes all the source code contained in the book.I bought two of these, one for home and one for the office, and I suggest you do the same.
Slepp, Atlanta, GA, USA.

3 Stars Not bad, 22-May-2001
Good book but very unorganized and poor editing. There's some good information, but too little detail.
A Reader, Columbus, Ohio, USA.

5 Stars Totally and Utterly Amazing, 17-May-2001
This book is fantastic, it has everything for hackers and crackers. The easy to read nature and example packed nature of the book makes it a must for everyone! ... Buy it! go-on!
Scott Mackenzie, Bradford Uni, UK.

5 Stars I feel it now..., 12-May-2001
This book is very interesting, i've bought other books related to this subjecct and this one has new and informative information on the subject.
futcomker, Italy.

5 Stars Good Book, 19-Apr-2001
This book is great anything and everything you've ever wanted to know about hacking linux or protecting yourself is right here in this book.
A ...-year old reader, Pleasant Grove, Alabama, USA.

5 Stars Hatch and crew do it again!!!, 18-Apr-2001
Well, this seems to be a fitting follow up to the Hacking Exposed 2nd edition that came out earlier in the year. For those of us who have already read through this series?/book, you know how good they are. This book clearly illustrates hacking methods without holding anything back. Everything is shown in plain view in easy to understand language. In addition, this book can be read by security beginners and experts alike. A great read all around!!!
Jeffrey Tricoli, from Alexandria, Virginia USA.


(FatBrain has now merged with Barnes and Noble.com, but they didn't merge the reviews, it seems. 08-Apr-2002)

5 Stars (Untitled Review), 20-Aug-2001
I didn't like 'Hacking Exposed' because it was too broad. So this time they (or rather this new batch of authors) got it right. They picked one OS and really got into it. Want to secure a Linux machine? Read it here. Want to learn how to hack a Linux machine? Read it here. Want to learn how to point and click with a windows app? Go waste your time somewhere else, this book is for real hackers.

5 Stars (Untitled Review), 25-Jul-2001
I bought this book when it came out, and have read it several times. It's really taught me a lot about Linux problems. I can't recomend this book enough.

5 Stars (Untitled Review), 25-Jun-2001
I flipped through this book at the store, expecting another capitalize-on-the-hacker-scare book. Nope, not this one. Instead of frightening you with lots of made up stories, this book shows you the nitty gritty -- enough for you to become a hacker, or better to defend yourself against one. Lots of code, real and current examples, and solutions ready to implement in seconds. Do you connect to the internet on a Linux machine? Get this book, lest your machine be used by someone else.

Barnes and Noble

5 Stars Linux Exposed Really Tells All, 11-Apr-2002
This book really gives you tons of very valuble information. Most of witch you do not need to be a super advanced computer wizard to comprehend. I have learned a lot and my knowledge of the subjects covered has been exponentialy expanded. I highly recommend this book for anyone who is looking for computer safty from hackers and/or computer knowledge of highly used systems.
Casey, a informational eauntrpanure.

5 Stars Excellent Hacking Book!, 20-Aug-2001
I used to put 'Hacking Exposed' at the top of my security/hacking list, but it has finally been defeated. Not suprising it was by another in the same line. Hacking Linux Exposed delves much more than HE was able to (given that it covered so much). Want to learn how to secure your Linux machine by seeing into the hacker's eyes? Hacking Linux Exposed is for you.
David Wagner, paranoid security freak.

5 Stars Couldn't wait., 16-Jul-2001
I saw this book at the store and started flipping through it, and couldn't put it down. I knew I needed to have this book, because it contained so much information I wanted to read it while sitting at my machine. So I went home and ordered it online where it was cheeper which is what I normally do. However I couldn't help thinking about how vulnerable my machine was, so I went back and bought the copy at the store. Now I have two, one for home and one for school, and it was money well spent.
Ralph Jenkins, a student hacker.

5 Stars Secure it now., 13-Jul-2001
just got my copy in the mail and can't put it down. this book rocks. easy to read, well organized, and very detailed. it really shows you what hacks look like, and gives you the solution that'll keep you safe now and in the future.
The Dysc..

5 Stars A bible for a secure network., 09-Jul-2001
I flipped through this book at a friends house, and was shocked to see how much networking info was here. In spite of the fact that we don't have too many Linux machines at my office, I bought this book. The covered a ton of things that helped get our network into shape. We now have a dedicated Linux machine as a firewall and mail gateway protecting our other machines, and are logging (and denying) all the attacks we didn't know about before. We had no idea how vulnerable we were.
S. Moon, Network Engineer.

5 Stars Best Linux Hacking book out there, 18-Jun-2001
I've bought most of the linux books that have been written, and this is the only one I haven't given away after reading it. I find this to be an excellent resource, unlike most of the books low on content and high in scare tactics and pretty pictures. This book gives you the nitty gritty -- real code, real problems, and real answers. You want to keep the bad guys off your machine, this is the book you need. Forget the rest.
Emily Sanderson, Big 6 Security Consultant.

3 Stars OK, book!, 17-May-2001
This book has many hacking exposures, and utils. If your an above average security keeper, then theres no REAL need for this book. It does provide with great points and ways to keep hackers out, but not leet hackers ;)~~~ Every hacker needs to know anything there is and will be in computer security or exposures, so buy the book! not with a credit card though, go to the book store and buy with IN CASH! (keep the FBI off of you)
FUT (UNKNOWN@yahoo.com), a student... he he he.


5 Stars Outstanding Linux-focused update of a renown classic, 24-Aug-2001
Hacking Exposed is widely revered as an essential security reference, and the authors here have done one better by producing a Linux-focused version of the book that speaks to the specific security problems in Linux. I'd absolutely recommend it to anyone interested in securing their Linux systems.
Todd H, Chicago, IL USA.


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