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OverviewThe Hands-On, Practical Guide to Preventing Ajax-Related Security Vulnerabilities More and more Web sites are being rewritten as Ajax applications; even traditional desktop software is rapidly moving to the Web via Ajax. But, all too often, this transition is being made with reckless disregard for security. If Ajax applications aren’t designed and coded properly, they can be susceptible to far more dangerous security vulnerabilities than conventional Web or desktop software. Ajax developers desperately need guidance on securing their applications: knowledge that’s been virtually impossible to find, until now. Ajax Security systematically debunks today’s most dangerous myths about Ajax security, illustrating key points with detailed case studies of actual exploited Ajax vulnerabilities, ranging from MySpace’s Samy worm to MacWorld’s conference code validator. Even more important, it delivers specific, up-to-the-minute recommendations for securing Ajax applications in each major Web programming language and environment, including .NET, Java, PHP, and even Ruby on Rails. You’ll learn how to: · Mitigate unique risks associated with Ajax, including overly granular Web services, application control flow tampering, and manipulation of program logic · Write new Ajax code more safely—and identify and fix flaws in existing code · Prevent emerging Ajax-specific attacks, including JavaScript hijacking and persistent storage theft · Avoid attacks based on XSS and SQL Injection—including a dangerous SQL Injection variant that can extract an entire backend database with just two requests · Leverage security built into Ajax frameworks like Prototype, Dojo, and ASP.NET AJAX Extensions—and recognize what you still must implement on your own · Create more secure “mashup” applications Ajax Security will be an indispensable resource for developers coding or maintaining Ajax applications; architects and development managers planning or designing new Ajax software, and all software security professionals, from QA specialists to penetration testers. Full Product DetailsAuthor: Billy Hoffman , Bryan SullivanPublisher: Pearson Education (US) Imprint: Addison-Wesley Educational Publishers Inc Dimensions: Width: 17.60cm , Height: 2.60cm , Length: 23.20cm Weight: 0.720kg ISBN: 9780321491930ISBN 10: 0321491939 Pages: 504 Publication Date: 13 December 2007 Audience: College/higher education , Tertiary & Higher Education Format: Paperback Publisher's Status: Out of Print Availability: Out of stock ![]() Table of ContentsPreface xvii Preface (The Real One) xvix Chapter 1 Introduction to Ajax Security 1 An Ajax Primer 2 What Is Ajax? 2 Asynchronous 3 JavaScript 6 XML 11 Dynamic HTML (DHTML) 11 The Ajax Architecture Shift 11 Thick-Client Architecture 12 Thin-Client Architecture 13 Ajax: The Goldilocks of Architecture 15 A Security Perspective: Thick-Client Applications 16 A Security Perspective: Thin-Client Applications 17 A Security Perspective: Ajax Applications 18 A Perfect Storm of Vulnerabilities 19 Increased Complexity, Transparency, and Size 19 Sociological Issues 22 Ajax Applications: Attractive and Strategic Targets 23 Conclusions 24 Chapter 2 The Heist 25 Eve 25 Hacking HighTechVacations.net 26 Hacking the Coupon System 26 Attacking Client-Side Data Binding 32 Attacking the Ajax API 36 A Theft in the Night 42 Chapter 3 Web Attacks 45 The Basic Attack Categories 45 Resource Enumeration 46 Parameter Manipulation 50 Other Attacks 75 Cross-Site Request Forgery (CSRF) 75 Phishing 76 Denial-of-Service (DoS) 77 Protecting Web Applications from Resource Enumeration and Parameter Manipulation 77 Secure Sockets Layer 78 Conclusions 78 Chapter 4 Ajax Attack Surface 81 Understanding the Attack Surface 81 Traditional Web Application Attack Surface 83 Form Inputs 83 Cookies 84 Headers 85 Hidden Form Inputs 86 Query Parameters 86 Uploaded Files 89 Traditional Web Application Attacks: A Report Card 90 Web Service Attack Surface 92 Web Service Methods 92 Web Service Definitions 94 Ajax Application Attack Surface 94 The Origin of the Ajax Application Attack Surface 96 Best of Both Worlds–for the Hacker 98 Proper Input Validation 98 The Problem with Blacklisting and Other Specific Fixes 99 Treating the Symptoms Instead of the Disease 102 Whitelist Input Validation 105 Regular Expressions 109 Additional Thoughts on Input Validation 109 Validating Rich User Input 111 Validating Markup Languages 111 Validating Binary Files 113 Validating JavaScript Source Code 114 Validating Serialized Data 120 The Myth of User-Supplied Content 122 Conclusion 123 Chapter 5 Ajax Code Complexity 125 Multiple Languages and Architectures 125 Array Indexing 126 String Operations 128 Code Comments 129 Someone Else’s Problem 130 JavaScript Quirks 132 Interpreted, Not Compiled 132 Weakly Typed 133 Asynchronicity 135 Race Conditions 135 Deadlocks and the Dining Philosophers Problem 139 Client-Side Synchronization 144 Be Careful Whose Advice You Take 144 Conclusions 145 Chapter 6 Transparency in Ajax Applications 147 Black Boxes Versus White Boxes 147 Example: MyLocalWeatherForecast.com 150 Example: MyLocalWeatherForecast.com “Ajaxified” 152 Comparison Conclusions 156 The Web Application as an API 156 Data Types and Method Signatures 158 Specific Security Mistakes 158 Improper Authorization 159 Overly Granular Server API 161 Session State Stored in JavaScript 164 Sensitive Data Revealed to Users 165 Comments and Documentation Included in Client-Side Code 166 Data Transformation Performed on the Client 167 Security through Obscurity 172 Obfuscation 173 Conclusions 174 Chapter 7 Hijacking Ajax Applications 175 Hijacking Ajax Frameworks 176 Accidental Function Clobbering 176 Function Clobbering for Fun and Profit 178 Hijacking On-Demand Ajax 184 Hijacking JSON APIs 190 Hijacking Object Literals 195 Root of JSON Hijacking 195 Defending Against JSON Hijacking 196 Conclusions 199 Chapter 8 Attacking Client-Side Storage 201 Overview of Client-Side Storage Systems 201 General Client-Side Storage Security 202 HTTP Cookies 204 Cookie Access Control Rules 206 Storage Capacity of HTTP Cookies 211 Lifetime of Cookies 215 Additional Cookie Storage Security Notes 216 Cookie Storage Summary 216 Flash Local Shared Objects 218 Flash Local Shared Objects Summary 225 DOM Storage 226 Session Storage 227 Global Storage 229 The Devilish Details of DOM Storage 231 DOM Storage Security 233 DOM Storage Summary 234 Internet Explorer userData 235 Security Summary 240 General Client-Side Storage Attacks and Defenses 240 Cross-Domain Attacks 241 Cross-Directory Attacks 242 Cross-Port Attacks 243 Conclusions 243 Chapter 9 Offline Ajax Applications 245 Offline Ajax Applications 245 Google Gears 247 Native Security Features and Shortcomings of Google Gears 248 Exploiting WorkerPool 251 LocalServer Data Disclosure and Poisoning 253 Directly Accessing the Google Gears Database 257 SQL Injection and Google Gears 258 How Dangerous Is Client-Side SQL Injection? 262 Dojo.Offline 264 Keeping the Key Safe 265 Keeping the Data Safe 266 Good Passwords Make for Good Keys 267 Client-Side Input Validation Becomes Relevant 268 Other Approaches to Offline Applications 270 Conclusions 270 Chapter 10 Request Origin Issues 273 Robots, Spiders, Browsers, and Other Creepy Crawlers 273 “Hello! My Name Is Firefox. I Enjoy Chunked Encoding, PDFs, and Long Walks on the Beach.” 275 Request Origin Uncertainty and JavaScript 276 Ajax Requests from the Web Server’s Point of View 276 Yourself, or Someone Like You 280 Sending HTTP Requests with JavaScript 282 JavaScript HTTP Attacks in a Pre-Ajax World 284 Hunting Content with XMLHttpRequest 286 Combination XSS/XHR Attacks in Action 290 Defenses 292 Conclusions 294 Chapter 11 Web Mashups and Aggregators 295 Machine-Consumable Data on the Internet 296 Early 90’s: Dawn of the Human Web 296 Mid 90s: The Birth of the Machine Web 297 2000s: The Machine Web Matures 298 Publicly Available Web Services 299 Mashups: Frankenstein on the Web 301 ChicagoCrime.org 302 HousingMaps.com 303 Other Mashups 304 Constructing Mashups 304 Mashups and Ajax 306 Bridges, Proxies, and Gateways–Oh My! 308 Ajax Proxy Alternatives 309 Attacking Ajax Proxies 310 Et Tu, HousingMaps.com? 312 Input Validation in Mashups 314 Aggregate Sites 317 Degraded Security and Trust 324 Conclusions 327 Chapter 12 Attacking the Presentation Layer 329 A Pinch of Presentation Makes the Content Go Down 329 Attacking the Presentation Layer 333 Data Mining Cascading Style Sheets 334 Look and Feel Hacks 337 Advanced Look and Feel Hacks 341 Embedded Program Logic 345 Cascading Style Sheets Vectors 347 Modifying the Browser Cache 348 Preventing Presentation Layer Attacks 352 Conclusion 353 Chapter 13 JavaScript Worms 355 Overview of JavaScript Worms 355 Traditional Computer Viruses 356 JavaScript Worms 359 JavaScript Worm Construction 361 JavaScript Limitations 363 Propagating JavaScript Worms 364 JavaScript Worm Payloads 364 Putting It All Together 372 Case Study: Samy Worm 373 How It Worked 374 The Virus’ Payload 377 Conclusions About the Samy Worm 379 Case Study: Yamanner Worm (JS/Yamanner-A) 380 How It Worked 380 The Virus’ Payload 383 Conclusions About the Yamanner Worm 384 Lessons Learned from Real JavaScript Worms 387 Conclusions 389 Chapter 14 Testing Ajax Applications 391 Black Magic 391 Not Everyone Uses a Web Browser to Browse the Web 396 Catch-22 398 Security Testing Tools–or Why Real Life Is Not Like Hollywood 399 Site Cataloging 400 Vulnerability Detection 401 Analysis Tool: Sprajax 403 Analysis Tool: Paros Proxy 406 Analysis Tool: LAPSE (Lightweight Analysis for Program Security in Eclipse) 408 Analysis Tool:WebInspect™ 409 Additional Thoughts on Security Testing 411 Chapter 15 Analysis of Ajax Frameworks 413 ASP.NET 413 ASP.NET AJAX (formerly Atlas) 414 ScriptService 417 Security Showdown: UpdatePanel Versus ScriptService 419 ASP.NET AJAX and WSDL 420 ValidateRequest 424 ViewStateUserKey 425 ASP.NET Configuration and Debugging 426 PHP 427 Sajax 427 Sajax and Cross-Site Request Forgery 430 Java EE 431 Direct Web Remoting (DWR) 432 JavaScript Frameworks 434 A Warning About Client-Side Code 435 Prototype 435 Conclusions 437 Appendix A Samy Source Code 439 Appendix B Source Code for Yamanner Worm 447 Index 453ReviewsAuthor InformationBilly Hoffman is the lead researcher for HP Security Labs of HP Software. At HP, Billy focuses on JavaScript source code analysis, automated discovery of Web application vulnerabilities, and Web crawling technologies. He has worked in the security space since 2001 after he wrote an article on cracking software for 2600, “The Hacker Quarterly,” and learned that people would pay him to be curious. Over the years Billy has worked a variety of projects including reverse engineering file formats, micro-controllers, JavaScript malware, and magstripes. He is the creator of Stripe Snoop, a suite of research tools that captures, modifies, validates, generates, analyzes, and shares data from magstripes. Billy’s work has been featured in Wired, Make magazine, Slashdot, G4TechTV, and in various other journals and Web sites. Billy is a regular presenter at hacker conferences including Toorcon, Shmoocon, Phreaknic, Summercon, and Outerz0ne and is active in the South East hacking scene. Occasionally the suits make him take off the black t-shirt and he speaks at more mainstream security events including RSA, Infosec, AJAXWorld, and Black Hat. Billy graduated from the Georgia Institute of Technology in 2005 with a BS in Computer Science with specializations in networking and embedded systems. He lives in Atlanta with his wife and two tubby and very spoiled cats. Bryan Sullivan is a software development manager for the Application Security Center division of HP Software. He has been a professional software developer and development manager for over 12 years, with the last five years focused on the Internet security software industry. Prior to HP, Bryan was a security researcher for SPI Dynamics, a leading Web application security company acquired by HP in August 2007.While at SPI, he created the DevInspect product, which analyzes Web applications for security vulnerabilities during development. Bryan is a frequent speaker at industry events, most recently AjaxWorld, Black Hat, and RSA. He was involved in the creation of the Application Vulnerability Description Language (AVDL) and has three patents on security assessment and remediation methodologies pending review. He is a graduate of the Georgia Institute of Technology with a BS in Applied Mathematics. When he’s not trying to break the Internet, Bryan spends as much time as he can on the golf links. If any Augusta National members are reading this, Bryan would be exceedingly happy to tell you everything he knows about Ajax security over a round or two. Tab Content 6Author Website:Countries AvailableAll regions |