Table Of Content

137_hackapps_FC 6/19/01 3:48 PM Page 1 1YEAR UPGRADE BUYER PROTECTION PLAN ™ WW ee bb AA pp pp ll ii cc aa tt ii oo nn ss YYoo uu rr The Only Way to Stop a Hacker Is to Think Like One • Step-by-Step Instructions for Developing Secure Web Applications • Hundreds of Tools & Traps and Damage & Defense Sidebars and Security Alerts! • Complete Coverage of How to Hack Your Own Site Jeff Forristal FFrroomm tthhee aauutthhoorrss Julie Traxler Technical Editor ooff tthhee bbeesstt--sseelllliinngg HHAACCKK PPRROOOOFFIINNGG™™YYOOUURR NNEETTWWOORRKK 137_hackapps_FM 6/19/01 3:28 PM Page i s o l u t i o n s @ s y n g r e s s . c o m With more than 1,500,000 copies of our MCSE, MCSD, CompTIA, and Cisco study guides in print, we continue to look for ways we can better serve the information needs of our readers. One way we do that is by listening. Readers like yourself have been telling us they want an Internet-based service that would extend and enhance the value of our books. Based on reader feedback and our own strategic plan, we have created a Web site that we hope will exceed your expectations. [email protected] is an interactive treasure trove of useful information focusing on our book topics and related technologies. The site offers the following features: (cid:2) One-year warranty against content obsolescence due to vendor product upgrades. You can access online updates for any affected chapters. (cid:2) “Ask the Author”™ customer query forms that enable you to post questions to our authors and editors. (cid:2) Exclusive monthly mailings in which our experts provide answers to reader queries and clear explanations of complex material. (cid:2) Regularly updated links to sites specially selected by our editors for readers desiring additional reliable information on key topics. Best of all, the book you’re now holding is your key to this amazing site. Just go to www.syngress.com/solutions, and keep this book handy when you register to verify your purchase. Thank you for giving us the opportunity to serve your needs. And be sure to let us know if there’s anything else we can do to help you get the max- imum value from your investment. We’re listening. www.syngress.com/solutions 137_hackapps_FM 6/19/01 3:28 PM Page ii 137_hackapps_FM 6/19/01 3:28 PM Page iii 1YEAR UPGRADE BUYER PROTECTION PLAN ™ WWee bb AA pp pp ll ii cc aa tt ii oo nn ss YYoo uu rr The Only Way to Stop a Hacker Is to Think Like One 137_hackapps_FM 6/19/01 3:28 PM Page iv Syngress Publishing,Inc.,the author(s),and any person or firm involved in the writing,editing,or production (collectively “Makers”) of this book (“the Work”) do not guarantee or warrant the results to be obtained from the Work. There is no guarantee of any kind,expressed or implied,regarding the Work or its contents.The Work is sold AS IS and WITHOUT WARRANTY.You may have other legal rights,which vary from state to state. In no event will Makers be liable to you for damages,including any loss of profits,lost savings,or other incidental or consequential damages arising out from the Work or its contents.Because some states do not allow the exclusion or limitation of liability for consequential or incidental damages,the above limitation may not apply to you. You should always use reasonable case,including backup and other appropriate precautions,when working with computers,networks,data,and files. Syngress Media®,Syngress®,and “Career Advancement Through Skill Enhancement®,”are registered trademarks of Syngress Media,Inc. “Ask the Author™,”“Ask the Author UPDATE™,”“Mission Critical™,”and “Hack Proofing™”are trademarks of Syngress Publishing,Inc.Brands and product names mentioned in this book are trademarks or service marks of their respective companies. KEY SERIAL NUMBER 001 BN837R45G 002 AP9EEF4574 003 ZPHGJ264G8 004 BNJ3RG22TS 005 356YH8LLQ2 006 CF4H6J8MMX 007 22D56G7KM6 008 6B8MDD4G6Z 009 L9MNG542FR 010 BY45MQ98WA PUBLISHED BY Syngress Publishing,Inc. 800 Hingham Street Rockland,MA 02370 Hack Proofing Your Web Applications Copyright © 2001 by Syngress Publishing,Inc.All rights reserved.Printed in the United States of America. Except as permitted under the Copyright Act of 1976,no part of this publication may be reproduced or distributed in any form or by any means,or stored in a database or retrieval system,without the prior written permission of the publisher,with the exception that the program listings may be entered,stored,and executed in a computer system,but they may not be reproduced for publication. Printed in the United States of America 1 2 3 4 5 6 7 8 9 0 ISBN: 1-928994-31-8 Technical edit by:Julie Traxler Freelance Editorial Manager:Maribeth Corona-Evans Technical review by:Robert Hansen and Kevin Ziese Copy edit by:Darren Meiss and Beth A.Roberts Co-Publisher:Richard Kristof Index by:Jennifer Coker Developmental Editor:Kate Glennon Page Layout and Art by:Shannon Tozier Acquisitions Editor:Catherine B.Nolan Cover Design by:Michael Kavish Distributed by Publishers Group West in the United States. 137_hackapps_FM 6/19/01 3:28 PM Page v Acknowledgments We would like to acknowledge the following people for their kindness and support in making this book possible. Richard Kristof and Duncan Anderson of Global Knowledge,for their generous access to the IT industry’s best courses,instructors and training facilities. Ralph Troupe,Rhonda St.John,and the team at Callisma for their invaluable insight into the challenges of designing,deploying and supporting world-class enterprise networks. Karen Cross,Lance Tilford,Meaghan Cunningham,Kim Wylie,Harry Kirchner,Bill Richter,Kevin Votel,and Brittin Clark of Publishers Group West for sharing their incredible marketing experience and expertise. Mary Ging,Caroline Hird,Simon Beale,Caroline Wheeler,Victoria Fuller,Jonathan Bunkell,and Klaus Beran of Harcourt International for making certain that our vision remains worldwide in scope. Anneke Baeten,Annabel Dent,and Laurie Giles of Harcourt Australia for all their help. David Buckland,Wendi Wong,Daniel Loh,Marie Chieng,Lucy Chong,Leslie Lim, Audrey Gan,and Joseph Chan of Transquest Publishers for the enthusiasm with which they receive our books. Kwon Sung June at Acorn Publishing for his support. Ethan Atkin at Cranbury International for his help in expanding the Syngress program. Joe Pisco,Helen Moyer,and the great folks at InterCity Press for all their help. vv 137_hackapps_FM 6/19/01 3:28 PM Page vi 137_hackapps_FM 6/19/01 3:28 PM Page vii Contributors Chris Broomes (MCSE,MCT,MCP+I,CCNA) is a Senior Network Analyst at DevonIT (www.devonitnet.com),a leading networking services provider specializing in network security and VPN solutions.Chris has worked in the IT industry for over eight years and has a wide range of technical experience.Chris is Founder and President of Infinite Solutions Group Inc.(www.infinitesols.com),a network consulting firm located in Lansdowne,PA that specializes in network design,integration,security services,technical writing,and training.Chris is currently pursuing the CCDA and CCNP certifications while mastering the workings of Cisco and Netscreen VPN and security devices. Jeff Forristal is the Lead Security Developer for Neohapsis,a Chicago-based security solution/consulting firm.Apart from assisting in network security assessments and application security reviews (including source code review),Jeff is the driving force behind Security Alert Consensus,a joint security alert newsletter published on a weekly basis by Neohapsis,Network Computing,and the SANS Institute. Drew Simonis (CCNA) is a Security Consultant for Fiderus Strategic Security and Privacy Services.He is an information-security specialist with experience in security guidelines,incident response, intrusion detection and prevention,and network and system administration.He has extensive knowledge of TCP/IP data networking and Unix (specifically AIX and Solaris),as well as sound knowledge of routing,switching,and bridging.Drew has been involved in several large-scale Web development efforts for companies such as AT&T, IBM,and several of their customers.This has included both planning and deployment of such efforts as online banking,automated customer care,and an online adaptive insurability assessment used by a major vii 137_hackapps_FM 6/19/01 3:28 PM Page viii national insurance company.Drew helps customers of his current employer with network and application security assessments as well as assisting in ongoing development efforts.Drew is a member of MENSA and holds several industry certifications,including IBM Certified Specialist,AIX 4.3 System Administration,AIX 4.3 Communications,Sun Microsystems Certified Solaris System Administrator,Sun Microsystems Certified Solaris Network Administrator,Checkpoint Certified Security Administrator,and Checkpoint Certified Security Engineer.He resides in Tampa,FL. Brian Bagnall (Sun Certified Java Programmer and Developer) is co- author of the Sun Certified Programmer for Java 2 Study Guide.He is currently the lead programmer at IdleWorks,a company located in Western Canada.IdleWorks develops distributed processing solutions for large and medium-sized businesses with supercomputing needs.His background includes working for IBM developing client-side applications.Brian is also a key programmer of Lejos,a Java software development kit for Lego Mindstorms.Brian would like to thank his family for their support,and especially his father Herb. Michael Dinowitz hosts CF-Talk,the high-volume ColdFusion mailing list,out of House of Fusion.Com.He publishes and writes articles for the Fusion Authority Weekly News Alert (www.fusionau- thority.com/alert).Michael is the author of Fusebox:Methodology and Techniques (ColdFusion Edition) and is the co-author of the best- selling ColdFusion Web Application Construction Kit.Whether it’s researching the lowest levels of ColdFusion functionality or presenting to an audience,Michael’s passion for the language is clear.Outside of Allaire,there are few evangelists as dedicated to the spread of the language and the strengthening of the community. Jay D. Dyson is a Senior Security Consultant for OneSecure Inc.,a trusted provider of managed digital security services.Jay also serves as part-time Security Advisor to the National Aeronautics and Space viii 137_hackapps_FM 6/19/01 3:28 PM Page ix Administration (NASA).His extracurricular activities include main- taining Treachery.Net and serving as one of the founding staff mem- bers of Attrition.Org. Joe Dulay (MCSD) is the Vice-President of Technology for the IT Age Corporation.IT Age Corporation is a project management and software development firm specializing in customer-oriented business enterprise and e-commerce solutions located in Atlanta,GA.His current responsibilities include managing the IT department,heading the technology steering committee,software architecture,e-commerce product management,and refining development processes and method- ologies.Though most of his responsibilities lay in the role of manager and architect,he is still an active participant of the research and development team.Joe holds a bachelor’s degree from the University of Wisconsin in computer science.His background includes positions as a Senior Developer at Siemens Energy and Automation,and as an inde- pendent contractor specializing in e-commerce development.Joe would like to thank his family for always being there to help him. Michael Cross (MCSE,MCPS,MCP+I,CNA) is a Microsoft Certified System Engineer,Microsoft Certified Product Specialist, Microsoft Certified Professional + Internet,and a Certified Novell Administrator.Michael is the Network Administrator,Internet Specialist,and a Programmer for the Niagara Regional Police Service. He is responsible for network security and administration,programming applications,and Webmaster of their Web site at www.nrps.com. He has consulted and assisted in computer-related/Internet criminal cases and is part of an Information Technology team that provides support to a user base of over 800 civilian and uniform users. Michael owns KnightWare,a company that provides consulting, programming,networking,Web page design,computer training,and other services.He has served as an instructor for private colleges and technical schools in London,Ontario Canada.He has been a freelance writer for several years and has been published over two dozen times ix