Forwarded From: seceduat_private Originally From: Mich Kabay <mkabayat_private> ICSA PROJECT(S): FWPD, IDPD, INFOWAR, ROSE, TECH Intrusion Detection: Network Security Beyond the Firewall by Terry Escamilla (1998). John Wiley & Sons (New York). ISBN 0-471- 29000-9. xx + 348pp. Index. Review by M. E. Kabay, PhD, CISSP Director of Education ICSA, Inc. Terry Escamilla, PhD, has many years of experience designing and implementing information security systems. After He worked with Haystack Labs on the Stalker intrusion detection products and currently works on IBM's e-commerce products. Dr Escamilla has written a concise introduction not only to intrusion detection systems but also an excellent primer on important elements of modern information security. Intrusion Detection begins with a clear Preface that explains the purpose of his textbook: "Our goal is . . . To differentiate intrusion detection from other forms of computer security and to show how each product category adds value." The author explicitly avoids the shopping cart approach, leaving detailed product comparisons to the trade press where they belong in a rapidly-changing technical environment. He includes specific products as representatives of classes of software. Escamilla aims his book at CIOs and security officers or network managers; he wants to provide a high-level overview with enough technical detail to help the reader fit intrusion detection into corporate information security architectures. The book includes a good Introduction where Escamilla lays out the structure of his text. The first 153 pages serve in effect as a mini textbook introducing the conventional model for security -- the model focused on preventing breaches of security. The author uses the classical triad (C-I-A for confidentiality, integrity and availability) of security as a framework for reviewing traditional security; I strongly prefer Donn Parker's Hexad, which adds control or possession, authenticity and utility. Escamilla summarizes some of these in a mere paragraph. Nonetheless, his review is well worth reading by his intended audience and even by rank beginners in the field of security. The author's Chapter 1 definitions of security model, entities, subjects, objects, authorization, users, trust relationships, trust boundaries, reference monitor, security kernel, identification and authentication, access control schemes, and the other basics of security theory are lucid and well illustrated. For example, his paragraph on "Intrusion Detection and Monitoring" (p. 23) states, "The purpose of an IDS product is to monitor the system for attacks. An attack might be signaled by something as simple as a program that illegally modifies a user name. Complex attacks might involve sequences of events that span multiple systems. Intrusion detection products are classified with system monitors because they usually depend on auditing information provided from the system's logs or data gathered by sniffing network traffic. One difference between scanners and IDSs is the time interval. A scanner is running in real time when it is started. However, a scanner is rarely run all of the time. Intrusion detection products are designed to run in real time and to constantly monitor the system for attacks." I think that's admirably clear writing. In later chapters the author looks in a bit more detail at UNIX and Windows NT security. He summarizes hacker techniques such as password guessing, brute-force attacks, social engineering, Trojan horses, network sniffers, and exploitation of known vulnerabilities (bugs in software). Chapter 4, "Traditional Network Security Approaches," begins with a thorough review of how security protocols can include errors and how criminal hackers exploit weaknesses in those protocols. The author warns that designing distributed security particles is best left to knowledgeable, experienced experts. For example, he writes, "[a] distributed authentication protocol was designed using a challenge response technique, but the challenge and response were the same value. A hacker impersonating the recipient could just replay the challenge when asked for the response." Another example of a security blooper was "[a] protocol designed to accept incoming messages of a fixed length." The author writes, "Unfortunately, the program did not check the length of the incoming messages. . . and, because the system was a public Web server, any anonymous user on the Internet could crash the site." Chapter 4 also includes an extensive introduction to TCP/ IP and the kinds of attacks specific to these widely used protocols. In accordance with his principles, the author refuses to give detailed scripts that would allow uninformed users to generate such attacks; however, his clear explanations make it possible to understand the issues. The next six chapters--about 150 pages--are devoted to intrusion detection systems proper. This section includes details overviews of several important products. The products are used to illustrate important principles distinguishing different categories of products- many of which are complementary. Finally, in his last section, the author devotes two chapters to looking at appropriate responses to intrusion. He offers a sensible balance between ignoring intrusions and exerting extraordinary efforts to capture intruders. He very properly suggests that business considerations ought to determine the level of effort devoted to acting as a kind of wild-cyberwest sheriff. In any case, as he points out, it is often impossible to track intruders through the maze of jumps through other victimized sites. For this reason, he urges readers not to attack the proximate sites from which intrusions appear to be launched: too often, such sites are equally victims of the true attackers. The books ends very properly with a 16-page index that seems thorough and useful. As usual in any book, there are always picky little details that a reviewer seems bound to mention in order to demonstrate his or her attention to the text <smile>. I don't want to do that, although I cannot resist a broad grin at the following garbled sentence from page 201, "The answer lies in that recurring them on behalf of semantics." As an author who has groaned at what has appeared in print under my name, Dr Escamilla has my sincere sympathy. It happens to everyone. In summary, Dr. Escamilla's excellent book is well-written, comprehensive, and useful for both beginners and experts in information security. It is well worth its modest cost (U$40) and I hope that it will be widely used throughout the industry. For more information about the book, one can visit a section of the publisher's Web site <http://www.wiley.com/compbooks/escamilla>. In addition, readers will be interested to know that since this book went to press, a number of intrusion detection product developers banded together in December 1998 to form the ICSA's Intrusion Detection Product Developers Consortium <http://www.icsa.net/news/press_room/1998/idsc.shtml>. -o- Subscribe: mail majordomoat_private with "subscribe isn". Today's ISN Sponsor: Repent Security Incorporated [www.repsec.com]
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