Extrusion Detection: Security Monitoring for Internal Intrusions

Let's hear it for another exceptionally well written book on network monitoring. Aside from a very clearand easy to understand writing style, Richard hits home with practicality and rich detail. I've becomea big fan of his writings including those on his informative blog, [taosecurity].[blogspot.com].First, the praise. New material, different from that in Tao his former book, includes a more extensive lookat taps, along with defense and mitigation ( and lots of it), querying NMS data from databases, Ra tools, handlingNMS data properly and with care, and network design and filtering. There's a lot of discussion on implementingdefensive measures with Cisco products and proxies. I was glad to see more examples of argus use and theutilization of shell redirection to grab and format what you want. With that said, other things I really appreciatethat tend to be innate of Richards books are his heavy use of foot notes and citations, recommended and furtherreadings, explanations of all command-line options and arguments, methodical case-studies, and line numberand font emphasized addendum to help the reader focus on key elements when looking at large output.Richard also makes an effort to provide new tools and material not covered elsewhere as stated in his book.I always end up making notes of new tools to check out and play with. e.g. netsed, flowgrep, dhcpdump, ntsyslog.I especially enjoy his use of FreeBSD when choosing a platform, not because I think it's a good operating system ( I do),but because tech literature on the BSDs is not as abundant as it is for other operating systems. This will attract theinterest of newer and non-users.Finally, the criticism. This is probably less of the author but I really didn't like that the page numbers in this bookwere on the inside corners ( next to the binding) rather than the outside. You have to really open the book in roomsthat are not well lit to see the page numbers. There is a formatting error on pg 52 where the 22 foot note is:"Start Squid by simply executing squid.2 2" 22 is separated by what looks to be two spaces and the leastsignificant 2 :) runs into the letter "Y" on the word "You" in the next sentence. Again, less the author and morethe editor (maybe?), there's a mistake on page 100. In the sentence, "This means we could forge any TCP packetwith content uid=0(root0) and...", I believe the sentence means uid=0(root) rather than uid=0(root0). Personalrequests: I would have liked to seen more examples of BRO, rather than snort, a case study of a web app attack,and more use of ARGUS and its Ra tools.Conclusion: This book was informative and an enjoyable to read, I highly recommend it.

You don't need to be an Analyst within the government to find value here. The book gets into understanding ports, protocols and how they work to assist in determining odd traffic on the network. Today we have tools like ArcSight with serve up a lot of data to comb thru yet their courses do not teach you how to be an analyst. This book is based on teach anyone how to become a very good analyst.I started as an Analyst in 2003 and the first real event was one trying to get out of the network. So this book, while dated, has some great tools for IA analysts out there to use everyday. It's interesting how network flow is just becoming a tool we use regularly today. Mr. Bejtlich provides alot of basic tools here for anyone to learn and then use on their network.Can't wait to attend one of his classes.

Fantastic book

Following the success of 'The Tao of Network Security Monitoring' last year, world renowned security expert Richard Bejtlich raises once again the standard for security professionals, this time by focusing on analyzing threats coming from within our network - a kind of underestimated area.Traditionally, the point of network security is about keeping the bad guys out of a network ¡V ¡¥out¡¦ being where we hope they are to start with. Possible points of entry are considered to be devices accessible from the outside in some way, mostly servers and perhaps routers. Workstations with no address on the network have no apparent footprint that would betray their existence, so if potential intruders don't even know the hosts exist, and are unable to make any connection to them, how could they possibly exploit them? The truth is they can, in many ways, using not only technical skills but imagination and ability to exploit the human factor - against which no automated procedure or device can defend for long.Furthermore, many administrators put all their effort and resources into trying to design an impenetrable network infrastructure, but ignore the fact that every prevention measure is bound to fail at any moment. These administrators put little or no thought into the possibility of a real intrusion and, as a result, when it occurs the network infrastructure they've built doesn't allow them to cut their losses to a minimum, regain control in a timely manner and collect credible evidence that may lead to a future investigation.This, Richard Bejtlich's second book on the subject of network security, attempts to establish into readers' minds a solid grounding on how things are, while emphasizing common misconceptions of the past. By intentionally introducing concepts like 'Extrusion Detection', 'Defensible Network' and 'Pervasive Network Awareness' instead of relying on popular synonyms/counterparts, he addresses issues that have not been addressed - or given the appropriate importance - elsewhere.Extrusion Detection is an extraordinary book in the sense that it moves in parallel between theory and practice, suggesting ways of thinking or functioning and explaining how these could be implemented utilizing available software.Who should read this book?Everyone will find in this book valuable ideas never considered before. Well, of course this is a network-security book, so those that will directly benefit from it are administrators and architects of large networks - or anyone that expects to find himself in such position.What will you learn from this book?Richard Bejtlich's book will take you deeply into the following skills:- Designing defensible network infrastructures. As you will find out, a defensible network is a superset, and more accurate version, of what is referred to elsewhere as a 'secure network'. Given the fact that there can be no totally secure network, a defensible network is the best security status that can possibly be achieved through designing, monitoring, controlling and policing procedures.- Deploying Intrusion Detection/Prevention Systems in a way that will maximize their efficiency.- Following a series of technical practices to minimize the possibility of exposure of internal networks to the outside. Also dealing with the network effects of host-centric security threats like viruses, malware, trojans and worms, through traffic-control means.- Designing and following security policies that will minimize the resistance, detection and counter-reaction abilities of internal networks to any intruders.- Overcoming possible technical obstacles in order to have an appropriately monitored network, in other words achieving Pervasive Network Awareness. Available hardware and software products, as well as methods for their optimum deployment, are described in detail.- Utilizing well-established techniques, like routing and traffic filtering/control in multiple layers to increase the network's defensibility.- Capturing, analyzing, safekeeping and concentrating traffic in various levels. Making distinctions between malicious and legitimate traffic, detecting misconfiguration anomalies and taking the appropriate course of action in each circumstance.- Responding, in the event of an intrusion, in a way that will minimize the consequences and the extent of the intrusion while gathering, analyzing and preserving all possible evidence. Classifying/assessing any possible threat and making the best decisions in real-time.- Presenting evidence and conclusions derived by technical means, in a courtroom or to another, non-technical audience.Recommended skills to get the most out of this book:- Familiarity with basic networking and security concepts is required. You need to understand how TCP/IP works, how traffic filtering applies and how intruders commonly attack.- Familiarity with open source operating systems is highly recommended. Though the book is written in such a way that its concepts apply beyond specific operating systems or other software and any specific instructions serve only as examples, it is true that some of the best security-related products are only available for unix platforms, so you should know how to find your way around installing and configuring them.- Host-based security practices are not discussed, the reader is expected to know how to productively administer and secure the operating systems he deploys.- Some of the techniques discussed involve writing basic scripts to make their deployment worthwhile and/or possible. Basic understanding of programming principles and familiarity with some scripting language is highly recommended.- Extrusion detection does not differ in concept from intrusion detection. Any experience in intrusion detection techniques can easily be applied to extrusion detection and would be beneficial. Readers that are looking for a more thorough reading regarding those techniques are highly encouraged to read Richard Bejtlich's 'The TAO of Network Security Monitoring'.Conclusion: This is a must-read for all security professionals or enthusiasts, networking architects and administrators that like to know what's going on in their network. I am confident that 90% of everyone that read it will make haste to implement many of the valuable ideas suggested, right after they finish reading!

Il lavoro di Bejtlich si pone nell'ambito della sicurezza di rete. Contrariamente a quello che fanno decine di testi sull'argomento però, questo non tende a monitorare la rete per controllare e bloccare tentativi di accesso dall'esterno (internet) verso l'interno (server farm, DMZ).Bejtlich parte dal presupposto che le possibilità di attacco non sono soltanto i servizi esposti verso il mondo internet ma anche la parte client ovvero la LAN della network. Ormai esistono diversi attacchi che prendono di mira la parte client (browser exploit, phishing, XSS, etc.) ed è quindi molto probabile che durante le normali attività quotidiane un client del network possa divenire un bersaglio.Il testo propone diverse metodologie su come monitorare il traffico interno del network alla ricerca di dispositivi che cerchino di comunicare con l'esterno in modo non autorizzato. Implementando queste tecnologie risulta possibili prendere immediatamente atto di traffico non autorizzato quale ad esempio una botnet che cerca di comunicare con il proprio C&C attraverso il protocollo IRC e pervi rimedio.Ottima anche l'illustrazione di network difendibile visto come un network: MONITORABILE in qualsiasi punto dell'infrastruttura per verificare il tipo di traffico che circola, CONTROLLABILE in modo da permettere la gestione del flusso di pacchetti in base a regole precise (ACL), MINIMALE con la minima esposizione di servizi necessari sui singoli dispositivi e AGGIORNATO con la gestione sistematica degli aggiornamenti dei sistemi e degli applicativi.

Risk=Threat x Vulnerability x asset value リスクの本質とそれを意識した運用の大切さがよくわかる参考書です。