REVIEW: Beyond Fear, Bruce Schneier
It is instructive to view this book in light of another recent publication. Marcus Ranum, in “The Myth of Homeland Security” (cf. BKMYHLSC.RVW) [See Rob’s review in RISKS-23.02 and Marcus’s response in RISKS-23.14. PGN] complains that the DHS (Department of Homeland Security) is making mistakes, but provides only tentative and unlikely solutions. Schneier shows how security should work, and does work, presenting basic concepts in lay terms with crystal clarity. Schneier does not tell you how to prepare a security system as such, but does illustrate what goes on in the decision-making process.
Part one looks at sensible security. Chapter one points out that all security involves a balancing act between what you want and how badly you want it. An important distinction is also made between safety and security, and the material signals the danger of ignoring the commonplace in order to protect against the sensational but rare. Fundamental security concepts are outlined as well as risk analysis. Chapter two examines the effect (usually negative) that bias and subjective perceptions have on our inherent judgment of risks. Security policy is based on the agenda of the major players, and chapter three notes that we should evaluate security systems in that light.
Part two reviews how security works. Chapter four introduces systems and how they fail. “Know the enemy,” in chapter five, is not just a platitude: Schneier shows how an understanding of motivations allows you to assess the likelihood of different types of attack. Chapter six is less focused than those prior: it notes that attackers reuse old attacks with new technologies, but it is difficult to find a central thread as the text meanders into different topics. Finding a theme in chapter seven is also difficult: yes, technology creates imbalances in existing power structures, and, yes, complexity and common mechanisms do tend to weaken security positions, but the relationships between those facts is not as lucidly presented as in earlier material. The point of chapter eight, that you always have to be aware of the weakest link in the security chain, even when it changes, is more straightforward, but the relevance of the illustrations surrounding it is not always obvious. Resilience in security systems is important, but it is not clear why this needs to be addressed in a separate chapter nine when it could have been discussed in eight with defence in depth (or “class breaks” and single-points-of-failure in seven). The hurried ending is also very likely to confuse naive readers in regard to “fail-safe” and “fail- secure”: Schneier does not sufficiently stress the fact that the two concepts are not only different, but frequently in conflict. Chapter ten notes that people are both the strongest and weakest part of security: adaptable and resilient but terrible at detail; frequently surprisingly intuitive but often randomly foolish.
At this point the book is not only repetitive, but loses some of its earlier focus and structure. Detection and prevention are examined, in chapter eleven, not as part of the classic matrix of controls, but as yet another example or aspect of resilience. Most of the rest of the types of controls in the preventive/detective axis are listed in chapter twelve, lumped together as response. Chapter thirteen looks at identification, authentication, and authorization (but not accountability, which was seen, in the form of audit, in chapter eleven). Various types of countermeasures are described in chapter fourteen. Countermeasures with respect to terrorism are examined, in chapter fifteen, both in general terms and in light of the events of 9/11. What works is discussed, as well as what does not, and there is an interesting look at the different roles of the media in the US as contrasted with the UK.
Part three, entitled “The Game of Security,” is not clear as to purpose. Chapter sixteen starts off by pointing out that the five step assessment process is constant and never-ending–which begs the question of how to determine when diminishing returns start to set in on assessment itself. However, there is good material in regard to the actions you can take to influence decisions about security. A concluding editorial, in chapter seventeen, encourages the reader to move beyond fear and think realistically about security and the tradeoffs you are willing to make.
Some of the terms Schneier uses or invents may be controversial. His use of “active” and “passive” failures for the concepts more commonly known respectively as false rejection (false positive) or false acceptance (false negative) is probably much clearer, initially, to the naive reader. The concept is an important one, and so the presentation of it in this way could be a good thing. On the other hand, does “active failure” completely map to what is meant by “false acceptance,” and, if not, how much of a problem is created by the use of the new term? Similarly, “class break” does indicate the importance of new forms of attack, but the concept seems to partake aspects of defence in depth, single point of failure, and least common mechanism, all important constructs in their own right. Schneier’s invention of “default to insecure” is not really any more understandable than the more conventional terms of fail-safe or fail-open.
I recommend this book. Unlike Ranum’s, Beyond Fear has a more significant chance of informing and educating the public on vital issues of security. Security educators will find a treasure trove of ideas and examples that they can use to explain security concepts, to a variety of audiences. Security professionals are unlikely to find anything new in this material, but Schneier’s writing is always worth reading, and this work is refreshingly free of the grating of erroneous ideas.