REVIEWS FOR 24 DEADLY SINS OF SOFTWARE SECURITY “We are still paying for the security sins of the past and we are doomed to failure if we don’t learn from our history of poorly written software. From some of the most respected authors in the industry, this hard-hitting book is a must-read for any software developer or security zealot. Repeat after me–‘Thou shall not commit these sins!’” —George Kurtz, co-author of all six editions of Hacking Exposed and senior vice-president and general manager, Risk and Compliance Business Unit, McAfee Security “This little gem of a book provides advice on how to avoid 24 serious problems in your programs—and how to check to see if they are present in others. Their presentation is simple, straightforward, and thorough. They explain why these are sins and what can be done about them. This is an essential book for every programmer, regardless of the language they use. It will be a welcome addition to my bookshelf, and to my teaching material. Well done!” —Matt Bishop, Department of Computer Science, University of California at Davis “The authors have demonstrated once again why they’re the ‘who’s who’ of software security. The 24 Deadly Sins of Software Security is a tour de force for developers, security pros, project managers, and anyone who is a stakeholder in the development of quality, reliable, and thoughtfully-secured code. The book graphically illustrates the most common and dangerous mistakes in multiple languages (C++, C#, Java, Ruby, Python, Perl, PHP, and more) and numerous known-good practices for mitigating these vulnerabilities and ‘redeeming’ past sins. Its practical prose walks readers through spotting patterns that are predictive of sinful code (from high-level application functions to code-level string searches), software testing approaches, and harnesses for refining out vulnerable elements, and real-world examples of attacks that have been implemented in the wild. The advice and recommendations are similarly down-to-earth and written from the perspective of seasoned practitioners who have produced hardened—and usable—software for consumption by a wide range of audiences, from consumers to open source communities to large-scale commercial enterprises. Get this Bible of software security today, and go and sin no more!” —Joel Scambray, CEO of Consciere and co-author of the Hacking Exposed series This page intentionally left blank 24 DEADLY SINS OF SOFTWARE SECURITY Programming Flaws and How to Fix Them Michael Howard, David LeBlanc, and John Viega New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto Copyright © 2010 by The McGraw-Hill Companies. All rights reserved. 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To Jennifer, who has put up with many days of my working on a book, and to Michael for improving my writing skills on our fifth book together. —David To my family for simply putting up with me, and to David as he continues to find bugs in my code! —Michael This page intentionally left blank ABOUT THE AUTHORS Michael Howard is a principal security program manager on the Trustworthy Com- puting (TwC) Group’s Security Engineering team at Microsoft, where he is responsible for managing secure design, programming, and testing techniques across the company. Howard is an architect of the Security Development Lifecycle (SDL), a process for improving the security of Microsoft’s software. Howard began his career with Microsoft in 1992 at the company’s New Zealand office, working for the first two years with Windows and compilers on the Product Support Services team, and then with Microsoft Consulting Services, where he provided security infrastructure support to customers and assisted in the design of custom solutions and development of software. In 1997, Howard moved to the United States to work for the Windows division on Internet Information Services, Microsoft’s web server, before moving to his current role in 2000. Howard is an editor of IEEE Security & Privacy, is a frequent speaker at security-re- lated conferences, and regularly publishes articles on secure coding and design. Howard is the co-author of six security books, including the award-winning Writing Secure Code (Second Edition, Microsoft Press, 2003), 19 Deadly Sins of Software Security (McGraw-Hill Professional, 2005), The Security Development Lifecycle (Microsoft Press, 2006), and his most recent release, Writing Secure Code for Windows Vista (Microsoft Press, 2007). David LeBlanc, Ph.D., is a principal software development engineer for the Microsoft Office Trustworthy Computing group and in this capacity is responsible for designing and implementing security technology used in Microsoft Office. He also helps advise other developers on secure programming techniques. Since joining Microsoft in 1999, he has been responsible for operational network security and was a founding member of the Trustworthy Computing Initiative. David is the co-author of the award-winning Writing Secure Code (Second Edition, Microsoft Press, 2003), 19 Deadly Sins of Software Security (McGraw-Hill Professional, 2005), Writing Secure Code for Windows Vista (Microsoft Press, 2007), and numerous articles. John Viega, CTO of the SaaS Business Unit at McAfee, is the original author of the 19 deadly programming flaws that received press and media attention, and the first edition of this book is based on his discoveries. John is also the author of many other security books, including Building Secure Software (Addison-Wesley, 2001), Network Security with OpenSSL (O’Reilly, 2002), and the Myths of Security (O’Reilly, 2009). He is responsible for numerous software security tools and is the original author of Mailman, the GNU mail- ing list manager. He has done extensive standards work in the IEEE and IETF and co-in- vented GCM, a cryptographic algorithm that NIST has standardized. John is also an active advisor to several security companies, including Fortify and Bit9. He holds an MS and a BA from the University of Virginia. vii viii 24 Deadly Sins of Software Security About the Technical Editor Alan Krassowski is the Chief Architect of Consumer Applications at McAfee, Inc., where he heads up the design of the next generation of award-winning security protection products. Prior to this role, Alan led Symantec Corporation’s Product Security Team, helping product teams deliver more secure security and storage products.