Most organizations have a firewall, antivirus software, and intrusion detection systems, all of which are intended to keep attackers out. So why is computer security a bigger problem today than ever before? The answer is simple--bad software lies at the heart of all computer security problems. Traditional solutions simply treat the symptoms, not the problem, and usually do so in a reactive way. This book teaches you how to take a proactive approach to computer security. Building Secure Softwarecuts to the heart of computer security to help you get security right the first time. If you are serious about computer security, you need to read this book, which includes essential lessons for both security professionals who have come to realize that software is the problem, and software developers who intend to make their code behave. Written for anyone involved in software development and use-from managers to coders-this book is your first step toward building more secure software. Building Secure Softwareprovides expert perspectives and techniques to help you ensure the security of essential software. If you consider threats and vulnerabilities early in the devel-opment cycle you can build security into your system. With this book you will learn how to determine an acceptable level of risk, develop security tests, and plug security holes before software is even shipped. Inside you'll find the ten guiding principles for software security, as well as detailed coverage of: Software risk management for security Selecting technologies to make your code more secure Security implications of open source and proprietary software How to audit software The dreaded buffer overflow Access control and password authentication Random number generation Applying cryptography Trust management and input Client-side security Dealing with firewalls Only by building secure software can you defend yourself against security breaches and gain the confidence that comes with knowing you won't have to play the "penetrate and patch" game anymore. Get it right the first time. Let these expert authors show you how to properly design your system; save time, money, and credibility; and preserve your customers'trust.

"A book is a machine to think with." --I.A. RichardsPRINCIPLES OF LITERARY CRITICISM This book exists to help people involved in the software development process learn the principles necessary for building secure software. The book is intended foranyoneinvolved in software development, from managers to coders, although it contains the low-level detail that is most applicable to programmers. Specific code examples and technical details are presented in the second part of the book. The first part is more general and is intended to set an appropriate context for building secure software by introducing security goals, security technologies, and the concept of software risk management. There are plenty of technical books that deal with computer security, but until now, none have applied significant effort to the topic of developing secure programs. If you want to learn how to set up a firewall, lock down a single host, or build a virtual private network, there are other resources to which to turn outside this book. Because most security books are intended to address the pressing concerns of network-level security practitioners, they tend to focus on how to promote secrecy and how to protect networked resources in a world in which software is chronically broken. Unfortunately, many security practitioners have gotten used to a world in which having security problems in software is common, and even acceptable. Some people even assume that it is too hard to get developers to build secure software, so they don't raise the issue. Instead, they focus their efforts on "best-practice" network security solutions, erecting firewalls, and trying to detect intrusions and patch known security problems in a timely manner. We are optimistic that the problem of bad software security can be addressed. The truth is, writing programs that have no security flaws in themisdifficult. However, we assert that writing a "secure-enough" program is much easier than writing a completely bug-free program. Should people give up on removing bugs from software just because it's essentially impossible to eliminate them all? Of course not. By the same token, people shouldn't just automatically throw in the software security towel before they even understand the problem. A little bit of education can go a long way. One of the biggest reasons why so many products have security problems is that many technologists involved in the development process have never learned very much about how to produce secure code. One problem is that until now there have been very few places to turn for good information. A goal of this book is to close the educational gap and to arm software practitioners with the basic techniques necessary to write secure programs. This said, you should not expect to eradicate all security problems in your software simply by reading this book. Claiming that this book provides a silver bullet for security would ignore the realities of how difficult it is to secure computer software. We don't ignore reality--we embrace it, by treating software security as a risk management problem. In the real world, your software will likely never be totally secure. First of all, there is no such thing as 100% security. Most software has security risks that can be exploited. It's a matter of how much money and effort are required to break the system in question. Even if your software is bug free and your servers are protected by firewalls, someone who wants to target you may get an insider to attack you. Or they may perform a "black bag" (break-in) operation. Because security is complicated and is a system-wide property, we not only provide general principles for secure software design, but we also focus on the most common risks, and how to mitigate them. Organization This book is divided into two parts. The first part focuses on the things you should know about software securi