Foundations of Security : What Every Programmer Needs to Know

by Daswani, Neil

• ISBN13: 9781590597842
• ISBN10: 1590597842
• Format: Paperback
• Copyright: 2007-02-21
• Publisher: Apress

Summary

Information Technology is for everyone, not just geeks. But that means security is everyone's business, as you will discover in the pages of this excellent book! #8212 Vinton G. Cerf - a Founding Father of the InternetThis book serves as a great complement to the courses that make up the Stanford Center for Professional Development (SCPD) Security Certification Program. The book explains in detail how to defend against a wide range of attacks, and teaches principles of secure system design. #8212 Dr. Dan Boneh, Associate Professor, Computer Science and Electrical Engineering, Stanford UniversityFoundations of Security: What Every Programmer Needs to Knowteaches new and current software professionals state-of-the-art software security design principles, methodology, and concrete programming techniques they need to build secure software systems. Once youre enabled with the techniques covered in this book, you can start to alleviate some of the inherent vulnerabilities that make todays software so susceptible to attack. The book uses web servers and web applications as running examples throughout the book.For the past few years, the Internet has had a "wild, wild west" flavor to it. Credit card numbers are stolen in massive numbers. Commercial web sites have been shut down by Internet worms. Poor privacy practices come to light and cause great embarrassment to the corporations behind them. All these security-related issues contribute at least to a lack of trust and loss of goodwill. Often there is a monetary cost as well, as companies scramble to clean up the mess when they get spotlighted by poor security practices.It takes time to build trust with users, and trust is hard to win back. Security vulnerabilities get in the way of that trust.Foundations of Security: What Every Programmer Needs To Knowhelps you manage risk due to insecure code and build trust with users by showing how to write code to prevent, detect, and contain attacks. The lead author cofounded the Stanford Center for Professional Development Computer Security Certification. This book teaches you how to be more vigilant and develop a sixth sense for identifying and eliminating potential security vulnerabilities. Youll receive hands-on code examples for a deep and practical understanding of security. Youll learn enough about security to get the job done.

Table of Contents

Foreword	p. xv
About the Authors	p. xvii
About the Technical Reviewer	p. xix
Acknowledgments	p. xxi
Preface	p. xxiii
Security Design Principles
Security Goals	p. 3
Security Is Holistic	p. 3
Physical Security	p. 4
Technological Security	p. 4
Policies and Procedures	p. 6
Authentication	p. 7
Something You Know	p. 7
Something You Have	p. 8
Something You Are	p. 10
Final Notes on Authentication	p. 11
Authorization	p. 12
Access Control Lists (ACLs)	p. 13
Access Control Models	p. 14
The Bell-LaPadula Model	p. 15
Confidentiality	p. 17
Message/Data Integrity	p. 18
Accountability	p. 19
Availability	p. 20
Non-repudiation	p. 21
Concepts at Work	p. 22
Secure Systems Design	p. 25
Understanding Threats	p. 25
Defacement	p. 26
Infiltration	p. 26
Phishing	p. 27
Pharming	p. 28
Insider Threats	p. 28
Click Fraud	p. 29
Denial-of-Service (DoS)	p. 29
Data Theft and Data Loss	p. 30
Designing-In Security	p. 30
Windows 98	p. 31
The Internet	p. 31
Turtle Shell Architectures	p. 34
Convenience and Security	p. 35
SimpleWebServer Code Example	p. 35
Hypertext Transfer Protocol (HTTP)	p. 35
Code Walkthrough	p. 36
Security in Software Requirements	p. 44
Specifying Error Handling Requirements	p. 44
Sharing Requirements with Quality Assurance (QA)	p. 46
Handling Internal Errors Securely	p. 47
Including Validation and Fraud Checks	p. 48
Writing Measurable Security Requirements	p. 50
Security or Bust	p. 50
Security by Obscurity	p. 51
Flaws in the Approach	p. 51
SimpleWebServer Obscurity	p. 52
Things to Avoid	p. 55
Open vs. Closed Source	p. 57
A Game of Economics	p. 58
"Good Enough" Security	p. 59
Secure Design Principles	p. 61
The Principle of Least Privilege	p. 61
Defense-in-Depth	p. 63
Prevent, Detect, Contain, and Recover	p. 63
Don't Forget Containment and Recovery	p. 64
Password Security Example	p. 65
Diversity-in-Defense	p. 65
Securing the Weakest Link	p. 66
Weak Passwords	p. 66
People	p. 66
Implementation Vulnerabilities	p. 67
Fail-Safe Stance	p. 67
SimpleWebServer Fail-Safe Example	p. 67
Attempted Fix 1: Checking the File Length	p. 69
Attempted Fix 2: Don't Store the File in Memory	p. 69
Fix: Don't Store the File in Memory, and Impose a Download Limit	p. 70
Secure by Default	p. 71
Simplicity	p. 72
Usability	p. 73
Security Features Do Not Imply Security	p. 74
Exercises for Part 1	p. 77
Secure Programming Techniques
Worms and Other Malware	p. 83
What Is a Worm?	p. 83
An Abridged History of Worms	p. 84
The Morris Worm: What It Did	p. 84
The Morris Worm: What We Learned	p. 85
The Creation of CERT	p. 86
The Code Red Worm	p. 86
The Nimda Worm	p. 87
The Blaster and SQL Slammer Worms	p. 87
More Malware	p. 89
Buffer Overflows	p. 93
Anatomy of a Buffer Overflow	p. 93
A Small Example	p. 94
A More Detailed Example	p. 94
The safe_gets() Function	p. 98
Safe String Libraries	p. 100
Additional Approaches	p. 101
StackGuard	p. 101
Static Analysis Tools	p. 102
Performance	p. 103
Heap-Based Overflows	p. 103
Other Memory Corruption Vulnerabilities	p. 103
Format String Vulnerabilities	p. 104
Integer Overflows	p. 104
Client-State Manipulation	p. 107
Pizza Delivery Web Site Example	p. 108
Attack Scenario	p. 110
Solution 1: Authoritative State Stays at Server	p. 112
Solution 2: Signed State Sent to Client	p. 114
Using HTTP POST Instead of GET	p. 117
Cookies	p. 119
JavaScript	p. 121
SQL Injection	p. 123
Attack Scenario	p. 124
Solutions	p. 130
Why Blacklisting Does Not Work	p. 130
Whitelisting-Based Input Validation	p. 132
Escaping	p. 132
Second Order SQL Injection	p. 133
Prepared Statements and Bind Variables	p. 134
Mitigating the Impact of SQL Injection Attacks	p. 136
Password Security	p. 139
A Strawman Proposal	p. 139
Hashing	p. 141
Offline Dictionary Attacks	p. 143
Salting	p. 144
Online Dictionary Attacks	p. 150
Additional Password Security Techniques	p. 151
Strong Passwords	p. 151
"Honeypot" Passwords	p. 151
Password Filtering	p. 151
Aging Passwords	p. 152
Pronounceable Passwords	p. 152
Limited Login Attempts	p. 152
Artificial Delays	p. 152
Last Login	p. 153
Image Authentication	p. 153
One-Time Passwords	p. 154
Cross-Domain Security in Web Applications	p. 155
Interaction Between Web Pages from Different Domains	p. 156
HTML, JavaScript, and the Same-Origin Policy	p. 156
Possible Interactions of Documents from Different Origins	p. 157
HTTP Request Authentication	p. 159
Lifetime of Cached Cookies and HTTP Authentication Credentials	p. 160
Attack Patterns	p. 161
Cross-Site Request Forgery (XSRF)	p. 162
Cross-Site Script Inclusion (XSSI)	p. 164
Cross-Site Scripting (XSS)	p. 165
Preventing XSRF	p. 169
Inspecting Referer Headers	p. 170
Validation via User-Provided Secret	p. 170
Validation via Action Token	p. 171
Security Analysis of the Action Token Scheme	p. 173
Preventing XSSI	p. 176
Authentication via Action Token	p. 176
Restriction to POST Requests	p. 177
Preventing Resource Access for Cost Reasons	p. 177
Preventing XSS	p. 178
General Considerations	p. 179
Simple Text	p. 180
Tag Attributes (e.g., Form Field Value Attributes)	p. 181
URL Attributes (href and src)	p. 183
Style Attributes	p. 185
Within Style Tags	p. 186
In JavaScript Context	p. 186
JavaScript-Valued Attributes	p. 189
Redirects, Cookies, and Header Injection	p. 190
Filters for "Safe" Subsets of HTML	p. 191
Unspecified Charsets, Browser-Side Charset Guessing, and UTF-7 XSS Attacks	p. 192
Non-HTML Documents and Internet Explorer Content-Type Sniffing	p. 193
Mitigating the Impact of XSS Attacks	p. 194
Exercises for Part 2	p. 197
Introduction to Cryptography
Symmetric Key Cryptography	p. 203
Introduction to Encryption	p. 204
Substitution Ciphers	p. 204
Notation and Terminology	p. 205
Block Ciphers	p. 205
Security by Obscurity: Recap	p. 208
Encrypting More Data	p. 208
AES Code Example	p. 210
Stream Ciphers	p. 217
One-Time Pad	p. 217
RC4	p. 217
Steganography	p. 219
What Is Steganography?	p. 219
Steganography vs. Cryptography	p. 220
Asymmetric Key Cryptography	p. 221
Why Asymmetric Key Cryptography?	p. 221
RSA	p. 223
Elliptic Curve Cryptography (ECC)	p. 223
Symmetric vs. Asymmetric Key Cryptography	p. 224
Certificate Authorities	p. 224
Identity-Based Encryption (IBE)	p. 225
Authentication with Encryption	p. 225
Key Management and Exchange	p. 227
Types of Keys	p. 227
Identity Keys	p. 227
Conversation or Session Keys	p. 227
Integrity Keys	p. 228
Key Generation	p. 228
Random Number Generation	p. 229
The rand() function	p. 230
Random Device Files	p. 230
Random APIs	p. 231
Key (Secret) Storage	p. 231
Keys in Source Code	p. 231
Storing the Key in a File on Disk	p. 233
"Hard to Reach" Places	p. 233
Storing Secrets in External Devices	p. 233
Key Agreement and Exchange	p. 235
Using Asymmetric Keys	p. 236
Diffie-Hellman (DH)	p. 236
MACs and Signatures	p. 239
Secure Hash Functions	p. 239
Message Authentication Codes (MACs)	p. 240
CBC MACs	p. 240
HMAC	p. 241
Signatures	p. 242
Certificates and Certificate Authorities (CAs)	p. 243
Signing and Verifying	p. 246
Registration Authorities (RAs)	p. 246
Web of Trust	p. 247
Attacks Against Hash Functions	p. 247
SSL	p. 247
Server-Authenticated-Only	p. 248
Mutual Authentication	p. 249
Exercises for Part 3	p. 251
Appendixes
Defense-in-Depth: The FLI Model	p. 255
Protecting Against Failure	p. 256
Protecting Against Lies	p. 257
Protecting Against Infiltration	p. 257
Other Techniques	p. 258
Using an FLI-like Model	p. 258
References	p. 258
Source Code Listings	p. 261
References	p. 267
Index	p. 277
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