Applied Security Architecture and Threat Models
Internet attack on computer systems is pervasive. It can take from less than a minute to as much as eight hours for an unprotected machine connected to the Internet to be completely compromised. It is the information security architect’s job to prevent attacks by securing computer systems. This book describes both the process and the practice of assessing a computer system’s existing information security posture. Detailing the time-tested practices of experienced security architects, it explains how to deliver the right security at the right time in the implementation lifecycle.
Securing Systems: Applied Security Architecture and Threat Models covers all types of systems, from the simplest applications to complex, enterprise-grade, hybrid cloud architectures. It describes the many factors and prerequisite information that can influence an assessment. The book covers the following key aspects of security analysis:
- When should the security architect begin the analysis?
- At what points can a security architect add the most value?
- What are the activities the architect must execute?
- How are these activities delivered?
- What is the set of knowledge domains applied to the analysis?
- What are the outputs?
- What are the tips and tricks that make security architecture risk assessment easier?
To help you build skill in assessing architectures for security, the book presents six sample assessments. Each assessment examines a different type of system architecture and introduces at least one new pattern for security analysis. The goal is that after you’ve seen a sufficient diversity of architectures, you’ll be able to understand varied architectures and can better see the attack surfaces and prescribe security solutions.
Table of Contents
Foreword by John N. Stewart
Foreword by Dr. James F. Ransome
About the Author
Part I Introduction
The Lay of Information Security Land
The Structure of the Book
Breach! Fix It!
Information Security, as Applied to Systems
Applying Security to Any System
The Art of Security Assessment
Why Art and Not Engineering?
Introducing "The Process"
The Threat Landscape
Who Are These Attackers? Why Do They Want to Attack My System?
How Much Risk to Tolerate?
Security Architecture of Systems
Why Is Enterprise Architecture Important?
The "Security" in "Architecture"
Diagramming For Security Analysis
Seeing and Applying Patterns
System Architecture Diagrams and Protocol Interchange Flows (Data Flow Diagrams)
Security Touches All Domains
What Is "Architecturally Interesting"?
Understanding the Architecture of a System
Size Really Does Matter
Applying Principles and Patterns to Specific Designs
Principles, But Not Solely Principles
Information Security Risk
Rating with Incomplete Information
Gut Feeling and Mental Arithmetic
Personal Security Posture
Just Because It Might Be Bad, Is It?
The Components of Risk
Data Sensitivity Scales
The Risk Owner
Desired Security Posture
Prepare for Assessment
Credible Attack Vectors
Architecture and Artifacts
Understand the Logical and Component Architecture of the System
Understand Every Communication Flow and Any Valuable Data Wherever Stored
List All the Possible Threat Agents for This Type of System
List the Typical Attack Methods of the Threat Agents
List the System-Level Objectives of Threat Agents Using Their Attack Methods
Decompose (factor) the Architecture to a Level That Exposes Every Possible Attack Surface
Filter Out Threat Agents Who Have No Attack Surfaces Exposed to Their Typical Methods
List All Existing Security Controls for Each Attack Surface
Filter Out All Attack Surfaces for Which There Is Sufficient Existing Protection
A Few Additional Thoughts on Risk
Apply New Security Controls to the Set of Attack Services for Which There Isn’t Sufficient Mitigation
Build a Defense-in-Depth
Part I Summary
Part II Introduction
Practicing with Sample Assessments
Start with Architecture
A Few Comments about Playing Well with Others
Understand the Big Picture and the Context
Getting Back to Basics
Decompose the System
The Right Level of Decomposition
Finding Attack Surfaces to Build the Threat Model
Enterprise Architecture Pre-work: Digital Diskus
Digital Diskus’ Threat Landscape
Conceptual Security Architecture
Enterprise Security Architecture Imperatives and Requirements
Digital Diskus’ Component Architecture
Enterprise Architecture Requirements
Attack Surface Enumeration
Enterprise Identity Systems (Authentication and Authorization)
A Deployment Model Lens
More on Deployment Model
Endpoint AV Software Security Requirements
Mobile Security Software with Cloud Management
Basic Mobile Security Architecture
Mobility Often Implies Client/Cloud
Authentication Is Not a Panacea
The Entire Message Stack Is Important
Just Good Enough Security
Additional Security Requirements for a Mobile and Cloud Architecture
Cloud Software as a Service (SaaS)
What’s So Special about Clouds?
Analysis: Peel the Onion
Protecting Cloud Secrets
The Application Is a Defense
Additional Requirements for the SaaS Reputation Service 319
Part II Summary
Part III Introduction
Patterns and Governance Deliver Economies of Scale
Expressing Security Requirements
Expressing Security Requirements to Enable
Who Consumes Requirements?
Getting Security Requirements Implemented
Why Do Good Requirements Go Bad?
Some Thoughts on Governance
Building an Assessment Program
Building a Program
Senior Management’s Job
Use Peer Networks
Building a Team
Documentation and Artifacts
Mistakes and Missteps
Not Everyone Should Become an Architect
Standards Can’t Be Applied Rigidly
One Size Does Not Fit All, Redux
Don’t Issue Edicts Unless Certain of Compliance
Invitations Are Good!
Part III Summary and Afterword
Brook S.E. Schoenfield is Director of Product Security Architecture at Intel Security Group. He is the senior technical leader for software security across the division’s broad product portfolio. He has held leadership security architecture positions at high-tech companies for many years. Brook has presented at conferences such as RSA, BSIMM, and SANS What Works Summits on subjects within security architecture, including architecture risk assessment and threat models, information security risk, SaaS/Cloud security, and Agile security. He has been published by CRC Press, SANS, Cisco, and the IEEE.
"Brook Schoenfield has distilled a tremendous amount of practical experience and critical thinking about security architecture into a resource that should be extremely helpful to practitioners."
— Jack Jones, Originator of The Open Group Standard, Factor Analysis for Information Risk (FAIR)
"Five stars for Brook Schoenfield who has created a one-stop resource for both the security strategist/technologist and the executive suite, sounding the ‘proactive’ klaxon. The reader is given substantive exemplars on the practicality of architecting security solutions into the mix from the get-go, and obviating the tendency to ‘bolt on’ security at a later date. Securing Systems should be on every CSO’s and CISO’s desk, and referenced often as teams are built and security solutions architected."
— Christopher Burgess, CEO, Prevendra Inc, Author of Secrets Stolen, Fortunes Lost and Protecting Intellectual Property
"Brook Schoenfield’s approach to securing systems addresses the entire enterprise, not only its digital systems, as well as the processes and people who will interact, design, and build the systems. This book fills a significant gap in the literature and is appropriate for use as a resource for both aspiring and seasoned security architects alike."
— Dr. James F. Ransome, CISSP, CISM, Senior Director of Product Security at Intel Security Group and Co-Author of Core Software Security
"It is not good enough just to build something and try and secure it, it must be architected from the bottom up with security in it, by professionally trained and skilled security architects, checked and validated by regular assessments for weakness, and through a learning system that learns from today to inform tomorrow. We must succeed."
— John N. Stewart, SVP & Chief Security Officer, Cisco Security and Trust Organization and Winner of the CSO 40 Silver Award for the 2014 Chief Security Officer of the Year
"This book describes well why some companies are successful and some are not in the area of software security. Brook writes this book out of his own experiences from many years in the trade. I doubt that you can find many who have more years of great achievements in his field. By reading this book, you will get a fast track to build competence in a very advanced area. The possibilities to take the wrong route are much wider than you can imagine. Please do like me— read it and think how I can improve my daily business from what I have learned."
— Per-Olof Persson, Head of Software Security, Sony Mobile