If you already have one of these very popular and versatile routers, are in need of a good platform for small-scale network infrastructure, or want to use the WRT as a platform for penetration testing, then “Linksys WRT54G Ultimate Hacking” is a must-have. I read this book cover-to-cover this weekend, in-between moving things around for repairs to our kitchen and bathroom, and was very impressed with the content. In addition to the WRT54G running OpenWRT right now as my home network’s router, I have an untouched WRT54GS Version 3.0 sitting on my shelf right now. After reading this book, I can’t wait to pull it down and try some of the projects.
The form-factor is like any other Syngress book. What Syngress lacks in creative cover design, they make up for in consistency and readability. You can tell what book this is on your shelf from across the room, with the big red “LINKSYS WRT54G” dominating the title on the spine. At a glance, someone might think it’s the manual for the WRT54G, which isn’t far from the truth. After getting rid of the default firmware and going with one of the options from this book, “Linksys WRT54G Ultimate Hacking” should serve as a good manual for future activities. The back cover promises that you will be given access to a PDF version of the book by registering on-line for the Syngress “Solutions” program (free). This will be very useful, and will add to the value of this book for road warriors. At the time of writing this review, Syngress’ website hasn’t been updated to allow members to add this book to their Solutions account, though presumably it will be added soon.
Beyond being a simple how-to on flashing firmware, “Linksys WRT54G Ultimate Hacking” serves to present an entire body of knowledge on Linksys’ routers that the authors (Paul Asadoorian and Larry Pesce) have spent some time bringing together and testing. Most of the information in this book is out there on the Internet already, in various forum posts, mailing lists, wikis, and code repositories. However, unless you can afford to spend the time to sift through it for what’s useful to you, test it out, and work out the bugs, you are much better off getting this book. The authors have also supplied many external sources that the reader can refer to for more information, when things start getting out of the scope of the book.
The authors recognize that there are many different kinds of users that will want to run 3rd-party firmware on their Linksys routers, and helpfully break things down for each type. Everyone, from casual users who simply want a more stable firmware than the default, to (and of interest to this site) penetration testers, will find something useful in this book. More importantly, they can find what they need quickly, since the various user-types and projects are well organized and easy to find in the table of contents. The introduction to wireless security in Chapter 5 is very well written and will bring a lot of readers up to speed on the topic, at least in regard to securing their own networks.
The projects in the book are very interesting, especially those for penetration testers. I’m very interested in playing with Kismet on the WRT54G, the captive portal software, and using the router to set up VPN connections for remote testing. I may even get brave enough to crack one open and add an SD card slot. Scripts are presented for most projects, and for each, a link is given to the book’s website, where the authors may ensure that they are always available for download. Potential buyers of this book should be aware that some of the projects in the book require a router with a USB port (WRTSL54GS), including the spectrum analysis project discussed on the front cover.
My complaints about this book are small. There appear to be problems with the way some of the screenshots were printed. The ones in question (page 183, for example) are readable, but have a strange dark rectangle to the right that has a stretched version of a portion of the screenshot. Other figures are low resolution, and occasionally have obvious JPEG compression artefacts (such as on page 5). It never keeps the figure from being readable, although perhaps in future editions or books, figures could be created at the appropriate resolution and lossless format.
A chapter was cut from this book, “Chapter 7 - Developing Software for the WRT54G - Tools required, Coding and Testing, Making Packages”, that I believe would have been well-worth the additional space. Being able to develop and build one’s own packages is the logical next step for what is covered in this book, and would have given some insight to how the software used in the book’s projects were put together. This chapter would make an excellent addition to the book’s website, http://wrt54ghacks.com/ (which has potential to be a very good site).
Throughout the book, there are a few references to generating passwords using Steve Gibson’s web-based password generator at https://www.grc.com/passwords.htm. This is very surprising, considering the authors’ (completely warranted) distaste for Gibson on their podcast (Pauldotcom Security Weekly). Personally, despite the SSL, an assurance that passwords generated are not logged, and the fact that it’s labeled “Ultra High Security Password Generator”, I would not recommend that anyone use a web-based system for generating passwords. You’re involving an outsider that you can’t really measure how much you trust, when it’s just as easy to use software meant to run on your local machines to generate random passwords.
These complaints are not show stoppers and do not really impact the quality of this book. It’s very well written and brings together a body of knowledge that you won’t find in one place anywhere else. I would especially recommend it to security professionals who might be able to use OpenWRT as a platform for remote access, reconnaissance and exploitation.
