Building Secure Software: How to Avoid Security Problems the Right Way

Description

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 Software cuts 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 Software provides 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. Contents Foreword Preface Organization Code Examples Contacting Us Acknowledgments 1 Introduction to Software Security It’s All about the Software Dealing with Widespread Security Failures Bugtraq CERT Advisories RISKS Digest Technical Trends Affecting Software Security The ’ilities What Is Security? Isn’t That Just Reliability? Penetrate and Patch Is Bad On Art and Engineering Security Goals Prevention Traceability and Auditing Monitoring Privacy and Confidentiality Multilevel Security Anonymity Authentication Integrity Know Your Enemy: Common Software Security Pitfalls Software Project Goals Conclusion 2 Managing Software Security Risk An Overview of Software Risk Management for Security The Role of Security Personnel Software Security Personnel in the Life Cycle Deriving Requirements Risk Assessment Design for Security Implementation Security Testing A Dose of Reality Getting People to Think about Security Software Risk Management in Practice When Development Goes Astray When Security Analysis Goes Astray The Common Criteria Conclusion 3 Selecting Technologies Choosing a Language Choosing a Distributed Object Platform CORBA DCOM EJB and RMI Choosing an Operating System Authentication Technologies Host-Based Authentication Physical Tokens Biometric Authentication Cryptographic Authentication Defense in Depth and Authentication Conclusion 4 On Open Source and Closed Source Security by Obscurity Reverse Engineering Code Obfuscation Security for Shrink-Wrapped Software Security by Obscurity Is No Panacea The Flip Side: Open-Source Software Is the “Many-Eyeballs Phenomenon” Real? Why Vulnerability Detection Is Hard Other Worries On Publishing Cryptographic Algorithms Two More Open-Source Fallacies The Microsoft Fallacy The Java Fallacy An Example: GNU Mailman Security More Evidence: Trojan Horses To Open Source or Not to Open Source Another Security Lesson from Buffer Overflows Beating the Drum Conclusion 5 Guiding Principles for Software Security Principle 1: Secure the Weakest Link Principle 2: Practice Defense in Depth Principle 3: Fail Securely Principle 4: Follow the Principle of Least Privilege Principle 5: Compartmentalize Principle 6: Keep It Simple Principle 7: Promote Privacy Principle 8: Remember That Hiding Secrets Is Hard Principle 9: Be Reluctant to Trust Principle 10: Use Your Community Resources Conclusion 6 Auditing Software Architectural Security Analysis Attack Trees Reporting Analysis Findings Implementation Security Analysis Auditing Source Code Source-level Security Auditing Tools Using RATS in an Analysis The Effectiveness of Security Scanning of Software Conclusion 7 Buffer Overflows What Is a Buffer Overflow? Why Are Buffer Overflows a Security Problem? Defending against Buffer Overflow Major Gotchas Internal Buffer Overflows More Input Overflows Other Risks Tools That Can Help Smashing Heaps and Stacks Heap Overflows Stack Overflows Decoding the Stack To Infinity . . . and Beyond! Attack Code A UNIX Exploit What About Windows? Conclusion 8 Access Control The UNIX Access Control Model How UNIX Permissions Work Modifying File Attributes Modifying Ownership The umask The Programmatic Interface Setuid Programming Access Control in Windows NT Compartmentalization Fine-Grained Privileges Conclusion 9 Race Conditions What Is a Race Condition? Time-of-Check, Time-of-Use Broken passwd Avoiding TOCTOU Problems Secure File Access Temporary Files File Locking Other Race Conditions Conclusion 10 Randomness and Determinism Pseudo-random Number Generators Examples of PRNGs The Blum-Blum-Shub PRNG The Tiny PRNG Attacks Against PRNGs How to Cheat in On-line Gambling Statistical Tests on PRNGs Entropy Gathering and Estimation Hardware Solutions Software Solutions Poor Entropy Collection: How to Read “Secret” Netscape Messages Handling Entropy Practical Sources of Randomness Tiny Random Numbers for Windows Random Numbers for Linux Random Numbers in Java Conclusion 11 Applying Cryptography General Recommendations Developers Are Not Cryptographers Data Integrity Export Laws Common Cryptographic Libraries Cryptlib OpenSSL Crypto++ BSAFE Cryptix Programming with Cryptography Encryption Hashing Public Key Encryption Threading Cookie Encryption More Uses for Cryptographic Hashes SSL and TLS (Transport Layer Security) Stunnel One-Time Pads Conclusion 12 Trust Management and Input Validation A Few Words on Trust Examples of Misplaced Trust Trust Is Transitive Protection from Hostile Callers Invoking Other Programs Safely Problems from the Web Client-side Security Perl Problems Format String Attacks Automatically Detecting Input Problems Conclusion 13 Password Authentication Password Storage Adding Users to a Password Database Password Authentication Password Selection More Advice Throwing Dice Passphrases Application-Selected Passwords One-Time Passwords Conclusion 14 Database Security The Basics Access Control Using Views for Access Control Field Protection Security against Statistical Attacks Conclusion 15 Client-side Security Copy Protection Schemes License Files Thwarting the Casual Pirate Other License Features Other Copy Protection Schemes Authenticating Untrusted Clients Tamperproofing Antidebugger Measures Checksums Responding to Misuse Decoys Code Obfuscation Basic Obfuscation Techniques Encrypting Program Parts Conclusion 16 Through the Firewall Basic Strategies Client Proxies Server Proxies SOCKS Peer to Peer Conclusions Appendix A: Cryptography Basics The Ultimate Goals of Cryptography Attacks on Cryptography Types of Cryptography Symmetric Cryptography Types of Symmetric Algorithms Security of Symmetric Algorithms Public Key Cryptography Cryptographic Hashing Algorithms Other Attacks on Cryptographic Hashes What’s a Good Hash Algorithm to Use? Digital Signatures Conclusions References Index A B C D E F G H I J K L M N O P Q R S T U V W X Y