Building Secure and Reliable Systems

Copyright Table of Contents Foreword by Royal Hansen Foreword by Michael Wildpaner Preface Why We Wrote This Book Who This Book Is For A Note About Culture How to Read This Book Conventions Used in This Book O’Reilly Online Learning How to Contact Us Acknowledgments Part I. Introductory Material Chapter 1. The Intersection of Security and Reliability On Passwords and Power Drills Reliability Versus Security: Design Considerations Confidentiality, Integrity, Availability Confidentiality Integrity Availability Reliability and Security: Commonalities Invisibility Assessment Simplicity Evolution Resilience From Design to Production Investigating Systems and Logging Crisis Response Recovery Conclusion Chapter 2. Understanding Adversaries Attacker Motivations Attacker Profiles Hobbyists Vulnerability Researchers Governments and Law Enforcement Activists Criminal Actors Automation and Artificial Intelligence Insiders Attacker Methods Threat Intelligence Cyber Kill Chains™Tactics, Techniques, and Procedures Risk Assessment Considerations Conclusion Part II. Designing Systems Chapter 3. Case Study: Safe Proxies Safe Proxies in Production Environments Google Tool Proxy Conclusion Chapter 4. Design Tradeoffs Design Objectives and Requirements Feature Requirements Nonfunctional Requirements Features Versus Emergent Properties Example: Google Design Document Balancing Requirements Example: Payment Processing Managing Tensions and Aligning Goals Example: Microservices and the Google Web Application Framework Aligning Emergent-Property Requirements Initial Velocity Versus Sustained Velocity Conclusion Chapter 5. Design for Least Privilege Concepts and Terminology Least Privilege Zero Trust Networking Zero Touch Classifying Access Based on Risk Best Practices Small Functional APIs Breakglass Auditing Testing and Least Privilege Diagnosing Access Denials Graceful Failure and Breakglass Mechanisms Worked Example: Configuration Distribution POSIX API via OpenSSH Software Update API Custom OpenSSH ForceCommand Custom HTTP Receiver (Sidecar)Custom HTTP Receiver (In-Process)Tradeoffs A Policy Framework for Authentication and Authorization Decisions Using Advanced Authorization Controls Investing in a Widely Used Authorization Framework Avoiding Potential Pitfalls Advanced Controls Multi-Party Authorization (MPA)Three-Factor Authorization (3FA)Business Justifications Temporary Access Proxies Tradeoffs and Tensions Increased Security Complexity Impact on Collaboration and Company Culture Quality Data and Systems That Impact Security Impact on User Productivity Impact on Developer Complexity Conclusion Chapter 6. Design for Understandability Why Is Understandability Important?System Invariants Analyzing Invariants Mental Models Designing Understandable Systems Complexity Versus Understandability Breaking Down Complexity Centralized Responsibility for Security and Reliability Requirements System Architecture Understandable Interface Specifications Understandable Identities, Authentication, and Access Control Security Boundaries Software Design Using Application Frameworks for Service-Wide Requirements Understanding Complex Data Flows Considering API Usability Conclusion Chapter 7. Design for a Changing Landscape Types of Security Changes Designing Your Change Architecture Decisions to Make Changes Easier Keep Dependencies Up to Date and Rebuild Frequently Release Frequently Using Automated Testing Use Containers Use Microservices Different Changes: Different Speeds, Different Timelines Short-Term Change: Zero-Day Vulnerability Medium-Term Change: Improvement to Security Posture Long-Term Change: External Demand Complications: When Plans Change Example: Growing Scope—Heartbleed Conclusion Chapter 8. Design for Resilience Design Principles for Resilience Defense in Depth The Trojan Horse Google App Engine Analysis Controlling Degradation Differentiate Costs of Failures Deploy Response Mechanisms Automate Responsibly Controlling the Blast Radius Role Separation Location Separation Time Separation Failure Domains and Redundancies Failure Domains Component Types Controlling Redundancies Continuous Validation Validation Focus Areas Validation in Practice Practical Advice: Where to Begin Conclusion Chapter 9. Design for Recovery What Are We Recovering From?Random Errors Accidental Errors Software Errors Malicious Actions Design Principles for Recovery Design to Go as Quickly as Possible (Guarded by Policy)Limit Your Dependencies on External Notions of Time Rollbacks Represent a Tradeoff Between Security and Reliability Use an Explicit Revocation Mechanism Know Your Intended State, Down to the Bytes Design for Testing and Continuous Validation Emergency Access Access Controls Communications Responder Habits Unexpected Benefits Conclusion Chapter 10. Mitigating Denial-of-Service Attacks Strategies for Attack and Defense Attacker’s Strategy Defender’s Strategy Designing for Defense Defendable Architecture Defendable Services Mitigating Attacks Monitoring and Alerting Graceful Degradation A DoS Mitigation System Strategic Response Dealing with Self-Inflicted Attacks User Behavior Client Retry Behavior Conclusion Part III. Implementing Systems Chapter 11. Case Study: Designing, Implementing, and Maintaining a Publicly Trusted CA Background on Publicly Trusted Certificate Authorities Why Did We Need a Publicly Trusted CA?The Build or Buy Decision Design, Implementation, and Maintenance Considerations Programming Language Choice Complexity Versus Understandability Securing Third-Party and Open Source Components Testing Resiliency for the CA Key Material Data Validation Conclusion Chapter 12. Writing Code Frameworks to Enforce Security and Reliability Benefits of Using Frameworks Example: Framework for RPC Backends Common Security Vulnerabilities SQL Injection Vulnerabilities: TrustedSqlString Preventing XSS: SafeHtml Lessons for Evaluating and Building Frameworks Simple, Safe, Reliable Libraries for Common Tasks Rollout Strategy Simplicity Leads to Secure and Reliable Code Avoid Multilevel Nesting Eliminate YAGNI Smells Repay Technical Debt Refactoring Security and Reliability by Default Choose the Right Tools Use Strong Types Sanitize Your Code Conclusion Chapter 13. Testing Code Unit Testing Writing Effective Unit Tests When to Write Unit Tests How Unit Testing Affects Code Integration Testing Writing Effective Integration Tests Dynamic Program Analysis Fuzz Testing How Fuzz Engines Work Writing Effective Fuzz Drivers An Example Fuzzer Continuous Fuzzing Static Program Analysis Automated Code Inspection Tools Integration of Static Analysis in the Developer Workflow Abstract Interpretation Formal Methods Conclusion Chapter 14. Deploying Code Concepts and Terminology Threat Model Best Practices Require Code Reviews Rely on Automation Verify Artifacts, Not Just People Treat Configuration as Code Securing Against the Threat Model Advanced Mitigation Strategies Binary Provenance Provenance-Based Deployment Policies Verifiable Builds Deployment Choke Points Post-Deployment Verification Practical Advice Take It One Step at a Time Provide Actionable Error Messages Ensure Unambiguous Provenance Create Unambiguous Policies Include a Deployment Breakglass Securing Against the Threat Model, Revisited Conclusion Chapter 15. Investigating Systems From Debugging to Investigation Example: Temporary Files Debugging Techniques What to Do When You’re Stuck Collaborative Debugging: A Way to Teach How Security Investigations and Debugging Differ Collect Appropriate and Useful Logs Design Your Logging to Be Immutable Take Privacy into Consideration Determine Which Security Logs to Retain Budget for Logging Robust, Secure Debugging Access Reliability Security Conclusion Part IV. Maintaining Systems Chapter 16. Disaster Planning Defining “Disaster”Dynamic Disaster Response Strategies Disaster Risk Analysis Setting Up an Incident Response Team Identify Team Members and Roles Establish a Team Charter Establish Severity and Priority Models Define Operating Parameters for Engaging the IR Team Develop Response Plans Create Detailed Playbooks Ensure Access and Update Mechanisms Are in Place Prestaging Systems and People Before an Incident Configuring Systems Training Processes and Procedures Testing Systems and Response Plans Auditing Automated Systems Conducting Nonintrusive Tabletops Testing Response in Production Environments Red Team Testing Evaluating Responses Google Examples Test with Global Impact DiRT Exercise Testing Emergency Access Industry-Wide Vulnerabilities Conclusion Chapter 17. Crisis Management Is It a Crisis or Not?Triaging the Incident Compromises Versus Bugs Taking Command of Your Incident The First Step: Don’t Panic!Beginning Your Response Establishing Your Incident Team Operational Security Trading Good OpSec for the Greater Good The Investigative Process Keeping Control of the Incident Parallelizing the Incident Handovers Morale Communications Misunderstandings Hedging Meetings Keeping the Right People Informed with the Right Levels of Detail Putting It All Together Triage Declaring an Incident Communications and Operational Security Beginning the Incident Handover Handing Back the Incident Preparing Communications and Remediation Closure Conclusion Chapter 18. Recovery and Aftermath Recovery Logistics Recovery Timeline Planning the Recovery Scoping the Recovery Recovery Considerations Recovery Checklists Initiating the Recovery Isolating Assets (Quarantine)System Rebuilds and Software Upgrades Data Sanitization Recovery Data Credential and Secret Rotation After the Recovery Postmortems Examples Compromised Cloud Instances Large-Scale Phishing Attack Targeted Attack Requiring Complex Recovery Conclusion Part V. Organization and Culture Chapter 19. Case Study: Chrome Security Team Background and Team Evolution Security Is a Team Responsibility Help Users Safely Navigate the Web Speed Matters Design for Defense in Depth Be Transparent and Engage the Community Conclusion Chapter 20. Understanding Roles and Responsibilities Who Is Responsible for Security and Reliability?The Roles of Specialists Understanding Security Expertise Certifications and Academia Integrating Security into the Organization Embedding Security Specialists and Security Teams Example: Embedding Security at Google Special Teams: Blue and Red Teams External Researchers Conclusion Chapter 21. Building a Culture of Security and Reliability Defining a Healthy Security and Reliability Culture Culture of Security and Reliability by Default Culture of Review Culture of Awareness Culture of Yes Culture of Inevitably Culture of Sustainability Changing Culture Through Good Practice Align Project Goals and Participant Incentives Reduce Fear with Risk-Reduction Mechanisms Make Safety Nets the Norm Increase Productivity and Usability Overcommunicate and Be Transparent Build Empathy Convincing Leadership Understand the Decision-Making Process Build a Case for Change Pick Your Battles Escalations and Problem Resolution Conclusion Conclusion Appendix A. A Disaster Risk Assessment Matrix Index About the Editors Colophon