Book Review: “Applied Network Security Monitoring”

Chris Sanders kindly sent me a review copy of Applied Network Security Monitoring, written by Sanders along with Jason Smith, David J Bianco, and Liam Randall. It’s a very solid work, with much to recommend it to IT people who either have been told to implement security monitoring or who think that they should.

Some of Applied Network Security Monitoring will be very familiar to anyone who has read any other security book–I’ve read many times that risk equals impact times probability. Every book on this topic needs this information, however, and Sanders and company cover it in sufficient detail to ground a probie while letting the rest of us easily skim it as a refresher.

Then they take us through selecting data collection points and how they make decisions on where to collect data and what kind of data to collect. Ideally, of course, you collect full packet data everywhere, but in my semi-rural gigabit ISP world I don’t have enough electricity to spin that much disk. Where can you get by with session data, and where do you need full packet capture? ANSM takes you through the choices and the advantages and disadvantages of each, along with some guidance on the hardware needs.

Data is nice, but it’s what you do with the data that makes security analysis interesting. ANSM uses Security Onion as an underlying toolkit. Security Onion is huge, and contains myriad tools for any given purpose. There’s reasons for this–no one NSM tool is a perfect fit for all environments. ANSM chooses their preferred tools, such as Snort, Bro, and SiLK, and takes you through configuring and using them on the SO platform. Their choices give you honeypots and log management and all the functionality you expect.

Throughout the book you’ll find business and tactical advice. How do you organize a security team? How do you foster teamwork, retain staff, and deal with arrogant dweebs such as yours truly? (As an aside, ANSM contains the kindest and most business-driven description of the “give the arrogant guy enough rope to hang himself” tactic that I have ever read.) I’ve been working with the business side of IT for decades now, and ANSM taught me new tricks.

The part of the book that I found most interesting was the section on analysis. What is analysis, anyway? ANSM takes you through both differential analysis and relational analysis, and illustrates them with actual scenarios, actual data. Apparently I’m a big fan of differential diagnosis. I use it everywhere. For every problem. Fortunately, Sanders and crew include guidelines for when to try each type of analysis. I’ll have to try this “relational analysis” thing some time and see what happens.

Another interesting thing about ANSM is how it draws in lots of knowledge and examples from the medical field. Concepts like morbidity and mortality are very applicable to information technology in general, not just network security monitoring, and adding this makes the book both more useful and more interesting.

Applied Network Security Monitoring is a solid overview of the state of security analysis in 2014, and was well worth my time to read. It’s worth your time as well.

postscript

Not long ago, I reviewed Richard Bejtlich’s The Practice of Network Security Monitoring. What’s more, I have corresponded with both Sanders and Bejtlich, and while they aren’t “help me hide a body” friends I’d happily share a meal with either.

The obvious question people will ask is, how does Applied NSM compare to tPoNSM?

Both books use Security Onion. Each book emphasizes different tools, different methodologies, and different techniques. Practical NSM shows Bejtlich’s military background. While Sanders has worked with the military, Applied NSM reads like it’s from an IT background.

I can’t say either is a better book. Both are very very good.

Personally, I have never implemented any plan from a book exactly as written. I read books, note their advice, and build a plan that suits my environment, my budget, and–most importantly–my staff. Reading them, I picked between tools and strategies until I found something that would work for my site. Security monitoring is a complex field. Maintaining, let alone building, a security monitoring infrastructure requires constant sharpening of your skills.

I recommend anyone serious about the field read both books.