2 Securing the Cloud Cloud Computer Security Techniques and Tactics
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4 Securing the Cloud Cloud Computer Security Techniques and Tactics Vic (J.R.) Winkler Technical Editor Bill Meine AMSTERDAM BOSTON HEIDELBERG LONDON NEW YORK OXFORD PARIS SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO Syngress is an imprint of Elsevier
5 Acquiring Editor: Angelina Ward Development Editor: Matt Cater Project Manager: Jessica Vaughan Designer: Alisa Andreola Syngress is an imprint of Elsevier 225 Wyman Street, Waltham, MA 02451, USA 2011 Elsevier Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods or professional practices, may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information or methods described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. Library of Congress Cataloging-in-Publication Data Application submitted British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. ISBN: For information on all Syngress publications visit our website at Typeset by: diacritech, Chennai, India Printed in the United States of America
6 This book is dedicated to my parents Gernot and Renate, wife Rebecca, daughter Carra, and to Rebecca s father William Payne. Rebecca: Thank you for putting up with me (and not only because of this book) during this time. I owe you a great deal. Carra: You are embarking on your own story; watch your punctuation. Blue skies and may the wind always be at your back. My father-in-law William Payne passed away this past year. Bill embodied Southern charm and he left a legacy not only with his daughter but also as the Chief Engineer of the C130.
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8 Contents Acknowledgments xiii About the Author...xv About the Technical Editor xvii Introduction...xix CHAPTER 1 CHAPTER 2 Introduction to Cloud Computing and Security...1 Understanding Cloud Computing Cloud Scale, Patterns, and Operational Efficiency... 2 A Synergistic Trick Elasticity, Shape Shifting, and Security... 3 The IT Foundation for Cloud Cloud Computing as Foundation for Cloud Services Cloud Computing Qualities The Bottom Line An Historical View: Roots of Cloud Computing Decentralization and Proliferation Networking, the Internet, and the Web Virtualization...12 A Brief Primer on Security: From 50,000 ft...13 Terminology and Principles...14 Risk Management Security Must Become a Business Enabler...17 A Brief Primer on Architecture Systems Engineering...19 IT Architecture...20 Security Architecture: A Brief Discussion Defense in Depth Cloud Is Driving Broad Changes Cloud Works Today Valid Concerns Summary Endnotes Cloud Computing Architecture...29 Cloud Reference Architecture Revisiting Essential Characteristics Cloud Service Models Cloud Deployment Models...35 vii
9 viii Contents CHAPTER 3 Control over Security in the Cloud Model Cloud Application Programming Interfaces Making Sense of Cloud Deployment Public Clouds Private Clouds...40 Community Clouds Hybrid Clouds Making Sense of Services Models Cloud Software-as-a-Service...43 Cloud Platform-as-a-Service...43 Cloud Infrastructure-as-a-Service How Clouds Are Formed and Key Examples Using Virtualization to Form Clouds Using Applications or Services to Form Clouds...48 Real-world Cloud Usage Scenarios Virtualization Formed Clouds Application/Service Formed Clouds Hybrid Cloud Models...52 Summary Endnotes Security Concerns, Risk Issues, and Legal Aspects...55 Cloud Computing: Security Concerns A Closer Examination: Virtualization A Closer Examination: Provisioning A Closer Examination: Cloud Storage A Closer Examination: Cloud Operation, Security, and Networking Assessing Your Risk Tolerance in Cloud Computing...67 Assessing the Risk Information Assets and Risk Privacy and Confidentiality Concerns Data Ownership and Locale Concerns Auditing and Forensics Emerging Threats...73 So, Is It Safe? Legal and Regulatory Issues Third Parties Data Privacy Litigation Summary Endnotes....87
10 Contents ix CHAPTER 4 CHAPTER 5 Securing the Cloud: Architecture...89 Security Requirements for the Architecture Physical Security...91 Cloud Security Standards and Policies Cloud Security Requirements Security Patterns and Architectural Elements Defense In-depth Honeypots Sandboxes Network Patterns The Importance of a CMDB Cabling Patterns Resilience and Grace Planning for Change Cloud Security Architecture Cloud Maturity and How It Relates to Security Jericho Forum Representative Commercial Cloud Architectures Representative Cloud Security Architectures Planning Key Strategies for Secure Operation Classifying Data and Systems Define Valid Roles for Cloud Personnel and Customers Summary Endnotes Securing the Cloud: Data Security Overview of Data Security in Cloud Computing Control over Data and Public Cloud Economics Organizational Responsibility: Ownership and Custodianship Data at Rest Data in Motion Common Risks with Cloud Data Security Data Encryption: Applications and Limits Overview of Cryptographic Techniques Common Mistakes or Errors with Data Encryption Cloud Data Security: Sensitive Data Categorization Authentication and Identity Access Control Techniques Data Categorization and the Use of Data Labels Application of Encryption for Data at Rest
11 x Contents CHAPTER 6 CHAPTER 7 Application of Encryption for Data in Motion Impediments to Encryption in the Cloud Deletion of Data Data Masking Cloud Data Storage Cloud Lock-in (the Roach Motel Syndrome) Metadata AvoidingCloudLock-in(theRoachMotelSyndrome) Summary Endnotes Securing the Cloud: Key Strategies and Best Practices Overall Strategy: Effectively Managing Risk Risk Management: Stages and Activities Overview of Security Controls Cloud Security Controls Must Meet Your Needs NIST Definitions for Security Controls Unclassified Models Classified Model The Cloud Security Alliance Approach The Limits of Security Controls Security Exposure Will Vary over Time Exploits Don t Play Fair Best Practices Best Practices for Cloud Computing: First Principals Best Practices across the Cloud Community Other Best Practices for Cloud Computing: Cloud Service Consumers Other Best Practices for Cloud Computing: Cloud Service Providers Security Monitoring The Purpose of Security Monitoring Transforming an Event Stream The Need for C.I.A. in Security Monitoring The Opportunity for MaaS Summary Endnotes Security Criteria: Building an Internal Cloud Private Clouds: Motivation and Overview Security Implications: Shared versus Dedicated Resources
12 Contents xi CHAPTER 8 Considerations for Achieving Cost Savings Private Clouds: The Castle Keep? Analysis to Support Architecture Decisions Security Criteria for Ensuring a Private Cloud Network Considerations Data Center Considerations Operational Security Considerations Regulation Summary Endnotes Security Criteria: Selecting an External Cloud Provider Selecting a CSP: Overview of Assurance Vendor Claims and Independent Verification Selecting a CSP: Vendor Transparency Selecting a CSP: Overview of Risks Risk Will Vary by Customer and by CSP Assessing Risk Factors Selecting a CSP: Security Criteria Security Criteria: Revisiting Defense-in-depth Security Criteria: Other Considerations Additional Security-relevant Criteria Summary Endnotes CHAPTER 9 Evaluating Cloud Security: An Information Security Framework Evaluating Cloud Security Existing Work on Cloud Security Guidance or Frameworks Checklists for Evaluating Cloud Security Foundational Security Business Considerations Defense-in-depth Operational Security Metrics for the Checklists Summary Endnotes CHAPTER 10 Operating a Cloud From Architecture to Efficient and Secure Operations The Scope of Planning Physical Access, Security, and Ongoing Costs
13 xii Contents Logical and Virtual Access Personnel Security From the Physical Environment to the Logical Bootstrapping Secure Operations The Refinement of Procedures and Processes over Time Efficiency and Cost Security Operations Activities Server Builds Business Continuity, Backup, and Recovery Managing Changes in Operational Environments Information Security Management Vulnerability and Penetration Testing Security Monitoring and Response Best Practices Resilience in Operations Summary Endnotes Index...279
14 Acknowledgments I would like to thank Rachel Roumeliotis for contacting me out of the blue, first to act as Technical Editor for this book and later to assume the role of Author. I never imagined this to be both so hard and consuming. Oddly, I am thankful! We all come from somewhere I d like to thank two companies that no longer exist: Planning Research Corporation and Sun Microsystems. I can t begin to express the joy I felt at the many opportunities I discovered in both places. May the spirit of these companies persist. At PRC, Wayne Shelton and others presented me with one opportunity after another. At Sun Microsystems, I found myself in the heart of the Silicon Valley revolution. To many Sun Microsystems colleagues over the past few years: You taught me more than you ll ever know. To the incomparable Bill Meine, Thom Schoeffling, Joe Carvalho, Dan Butzer, Layne Jester, David Rodgers, Brian Foley, Dan Hushon, Jim Parkinson, Rinaldo DiGiorgio, and several dozen others whom I joined in designing and then building rather safe and rather cool platforms for grid and cloud computing: We achieved an incredible feat, several times over. At Sun, I learned the difference between marketing, innovation, engineering, and magic. But life goes on, and I have found new opportunities at Booz Allen Hamilton, so I would like to thank Bob Harbick, who convinced me to join his team of talented engineers. I am grateful for this experience as well. Did I thank Jimmy Page, Jimi Hendrix, and Tommy Bolin? O.K., here we go: Thank you Mordaunt-Short, Parasound, PS Audio, Apple Computer, the Google, late night TV, bad monster movies, uncertain walks in pitch dark with my dog Uli, great cigars, dangerously excellent spirits and wine, the attention my dog Bella lavishes on me, the truth of fiction, sea and air, mountains and snow, fireworks, a beautiful girl whose name I still remember after nearly 40 years, old friends, young friends, the existence of the power grid, the fact that NY is intact, and that star over there. I will again thank Bill Meine, who agreed to be the Technical Editor for this book. After many conversations with Bill, it is not surprising that many of his words and ideas should be in this book. Lastly, Matt Cater: Thank you for being a great shepherd for this project. xiii
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16 About the Author Vic (J.R.) Winkler is a Senior Associate at Booz Allen Hamilton, providing technical consultation to U.S. Government clients. He is a published InfoSec and cyber security researcher as well as an expert in intrusion/anomaly detection. At Sun Microsystems, Vic served as the Chief Technologist for Security for the Sun Public Cloud. He was also Chairman of the Board for the Sun Security Technology Ambassador program (presales security engineers). In 2010, he became a member of the Advisory Board for StratuScape (a Silicon Valley startup). Vic s background includes positions as an R&D principal investigator at Planning Research Corporation (PRC), where he was the lead designer and Program Manager for a trusted B1 UNIX OS. At PRC, he also conceived of and built one of the first network/host Intrusion Detection Systems (IDS). Vic has over 30 years experience in InfoSec/cyber security, cloud computing, systems and applications engineering, and IT operations and management. He has numerous technical conference publications, and as a visiting cyber security expert, Vic was the author of the Information Security policy for the Government of Malaysia. Vic resides in Reston, Virginia, with his family: Rebecca, Carra, Uli, Bella, and Toby. xv
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18 About the Technical Editor Bill Meine recently moved to the other side of the cloud delivery system by joining Software-as-a-Service startup Evergreen Energy, where he is the product owner for the agile software development effort. Part of his time is spent on the security concerns for delivering cloud service applications to customers in the power generation business. Previously, Bill was the chief architect for the infrastructure, security, and operations on Sun Microsystems public cloud, where he led the design of a large cloud infrastructure and operational processes that offered a leap in security at commodity prices. He instituted a lean manufacturing model with agile techniques for all aspects of the construction, development, and delivery of the cloud infrastructure. In his 25+ years at Sun, he was an architect for their dollar an hour public grid offering, enterprise IT architect, fly-and-fix smoke jumper, and staff engineer. Somewhere in his dark past, he wrote software for mine planning, controlling a laser-fusion experiment, and locating earthquakes. Bill lives in Denver, Colorado, with his family: Melinda and Kalen. xvii
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20 Introduction INFORMATION IN THIS CHAPTER Book Audience Terminology Risk, Perception of Risk and Cloud Computing Cloud Computing as a Tectonic Shift Structure of the Book Conclusion BOOK AUDIENCE This book will prove to be a practical resource for anyone who is considering using, building, or securing a cloud implementation. Security professionals may refer to this book as a source of detailed information for evaluating and verifying cloud security policy and requirements. Cloud infrastructure engineers, cloud services engineers, and integrators will find value in learning about relevant security approaches and cloud security architecture. It will also provide value to those who are interested in understanding cloud security. Executive-level management will gain an understanding of the security advantages and developing trends that are likely to mature as cloud computing progresses. TERMINOLOGY In this book, we use the term cloud in a broad way to refer to cloud computing and cloud services. Bycloud computing we mean: The Information Technology (IT) model for computing, which is composed of all the IT components (hardware, software, networking, and services) that are necessary to enable development and delivery of cloud services via the Internet or a private network. By cloud services, we mean those services that are expressed, delivered, and consumed over the Internet or a private network. Cloud services range from Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), and Software-as-a-Service (SaaS) and include everything else that uses these more basic services to create new services. These services may be deployed privately, publically, or in some combination. Cloud computing is far broader a field than public cloud services. There are different advantages and even risks in adopting either a private, community, public, or hybrid cloud deployment. Likewise, there are different value propositions and risks with the three main cloud services. xix
21 xx Introduction RISK, PERCEPTION OF RISK AND CLOUD COMPUTING A good way to view cloud computing is as a landscape that already offers great value and services, but one that is not yet at the Goldilocks stage, where every customer s computing needs are met by a just right solution. As a new paradigm for computing, cloud introduces challenges even as it offers advantages. Not all cloud deployment models (public, hybrid, private, and community) are appropriate for each service, each service customer, or all tenants. Likewise, it is not cost effective for all cloud providers to implement high assurance security or offer the same level of security. However, cloud computing is compelling, it is a rapidly growing trend in IT, and it is forcing significant advances in supporting technologies. In this book, we address some of the common security issues or questions that prospective cloud adopters face: Network Availability Network reliability is a key lynchpin for cloud computing and cloud services. Since a public cloud is by definition accessed over the Internet, the cloud provider must address the potential for catastrophic loss of Internet backbone connectivity. The same concern should be a primary consideration for cloud service consumers who entrust critical infrastructure to the cloud. Similar concerns exist for private clouds. Privacy and Data Data may not remain in the same system, the same data center, or within the same cloud provider s systems. Conceivably, data may even be stored in another country, incurring considerable concern. Control over Data A given user or organization s data may be comingled in storage or processing with data belonging to others. At minimum, data should be encrypted at the granularity of files belonging to given users or organizations. Cloud Provider Viability Since cloud providers are relatively new to the business, there are questions about provider viability and commitment. This concern is exacerbated when a provider requires that tenants use nonstandardsbased application program interfaces (APIs), thus effecting lock-in (impeding a tenant in migrating to an alternative provider). Security Incidents Tenants and users need to know what information the provider will share when an incident is discovered. This concern is related to questions about transparency that providers may offer into security processes, procedures, and internal policies. Disaster Recovery and Business Continuity Tenants and users must understand how they can continue their own operations and services if the underlying production environment is subject to a disaster. Systems Vulnerabilities and Risk of Common Attacks All software, hardware, and networking equipment is subject to exposure of new vulnerabilities. Some components may pose greater risks based on a history of vulnerabilities and exploits. Tenants may not tolerate specific vulnerabilities or risk areas for a range of reasons. A specific cloud may be subject to new attack types, or it may be immune to common attack types based on various reasons.
22 Introduction xxi Regulatory or Legislative Compliance It is difficult to utilize public clouds when your data is subject to legal restrictions or regulatory compliance. Building a cloud that can be certified may be challenging due to the current stage of cloud knowledge and best practices. CLOUD COMPUTING AS A TECTONIC SHIFT Cloud computing and cloud-based services (or cloud) are exciting for many reasons. Cloud is a significant step in the evolution of computing paradigms and a revolution in delivering IT services. At the same time, cloud threatens destabilization for the IT status quo. We appear to be at the early stages of a tectonic shift that will force changes in: Information security approaches, application development models, capital and operational expense decisions, and the IT operations workforce size and skill set. In many ways, cloud is breaking down our models of what we accept as being possible and even reasonable to do with computers. Being able to lease a dozen servers and have them be delivered in a fully provisioned manner within mere moments is astonishing, but doing so for a miniscule fraction of the traditional cost is revolutionary. Cloud computing has raised concerns about the erosion of control as information and software move off of organic resources and into someone else s IT management sphere. Despite concerns from many security professionals, cloud computing isn t innately more or less secure. But the cloud model does force a movement toward a more robust and capable foundation of security services. The mere act of transitioning from legacy systems gives us hope that we can regain control over gaps and issues that stem from poorly integrated or after-thought security. With cloud, greater investment for in-common security services has great potential for return on investment (ROI) given cloud scale. Even as it evolves and matures, cloud computing is being adopted at a fast pace. Despite the hype, cloud brings multiple fundamental shifts in how computing infrastructure is acquired and managed. Despite often shameless marketing by vendors and cloud providers, the opportunities with cloud computing may prove challenging to IT, business, and government. Already today, significant security concerns about cloud computing are coloring many early cloud adoption decisions. But we see cloud as a driver for better security, and we see security as an enabler and foundation for better cloud computing. STRUCTURE OF THE BOOK We begin by examining cloud computing in light of the continuing evolution of IT. Later, we will build a set of guidelines and simple tools that we can use to plan or evaluate security in different cloud deployment models and for different service models SaaS, PaaS, and IaaS. Together, we refer to these as the SPI
23 xxii Introduction service model. Developing guidelines entails a review and understanding of security principles, security risks, and security architecture. What we aim to do is to describe the security issues associated with cloud computing and how to apply security to cloud computing. We recognize that security requirements and solutions will vary greatly, and thus our underlying goal for the book is that the reader becomes better prepared to evaluate the conditions under which we should adopt Cloud Computing services and technologies. Chapters in This Book This book is organized in a top-down manner that begins with an introduction to cloud computing and security, progresses to an examination of cloud security architectures and issues, then presents a series of key strategies and best practices for cloud security, discusses the major security considerations for building or selecting a cloud provider, and concludes with an examination of what it means to securely operate a cloud. Chapter 1: Introduction to Cloud Computing and Security Chapter 1 Introduction to Cloud Computing and Security presents an overview to cloud computing along with its IT foundations, the historical underpinnings, and the cost benefits. Also covered are the essential qualities of clouds and a brief security and architecture background to support the remaining chapters. The bottom line with cloud computing is the combination of cost advantages it brings along with the pervasive changes it is unleashing. Chapter 2: Cloud Computing Architecture Chapter 2 CloudComputingArchitecture examines cloud computing, the NIST Cloud Computing Model, and identifies the essential characteristics of clouds. Also covered is the SPI cloud service model (SaaS, PaaS, and IaaS) along with the four cloud delivery models (public, private, hybrid, and community). The chapter also covers the relative degree of security control a tenant or consumer has with the different models. Chapter 3: Security Concerns, Risk Issues, and Legal Aspects Chapter 3 Security Concerns, Risk Issues, and Legal Aspects takes a closer look at the security concerns and issues with clouds along with surveying the legal and regulatory considerations of different types of clouds. Chapter 4: Securing the Cloud: Architecture Chapter 4 Securing the Cloud: Architecture identifies a number of security requirements for cloud computing. Proceeding from those requirements we identify common security patterns and architectural elements that make for better security. We then look at a few representative cloud security architectures and discuss several important aspects of those. This chapter also details several key
24 Introduction xxiii strategies that if considered during design can present considerable operational benefits. Chapter 5: Securing the Cloud: Data Security Chapter 5 Securing the Cloud: Data Security examines data security in cloud computing along with data protection methods and approaches. Cloud security countermeasures must comprise a resilient mosaic that protects data at rest and data in motion. Security concerns around storing data in the cloud are not inherently unique compared to data that is stored within the premises of an organization; nonetheless there are important considerations for security when adopting the cloud model. Chapter 6: Securing the Cloud: Key Strategies and Best Practices Chapter 6 Securing the Cloud: Key Strategies and Best Practices presents an overall cloud security strategy for effectively managing risk. Also covered is a treatment of cloud security controls and a discussion of the limits of security controls in cloud computing. The chapter also includes a detailed treatment of best practices for cloud security and a discussion of security monitoring for cloud computing. Chapter 7: Security Criteria: Building an Internal Cloud Chapter 7 Security Criteria: Building an Internal Cloud discusses the various motivations for embarking on a private cloud strategy along with an overview of what adopting a private cloud strategy entails in terms of benefits to both the enterprise and to security. The remainder of the chapter details the security criteria for a private cloud. Chapter 8: Security Criteria: Selecting an External Cloud Provider Chapter 8 Security Criteria: Selecting an External Cloud Provider ties together the material from the previous chapters in providing guidance for selecting a cloud service provider (CSP). In doing so, it addresses the gaps between vendor claims and the various aspects of information assurance, including those elements that are critical in selecting a CSP. That discussion includes an overview of vendor transparency and the prudent limits of disclosure. The chapter includes a discussion on the nature of risks in cloud computing along with the probability, impact affected assets, and factors that may be involved. The chapter concludes with a lengthy discussion of security criteria to enable selection of a CSP. Chapter 9: Evaluating Cloud Security: An Information Security Framework Chapter 9 Evaluating Cloud Security: An Information Security Framework builds on previous chapters and presents a framework for evaluating cloud security. This framework augments the security criteria identified in Chapter 8 and serves to provide a set of tools to evaluate the security of a private, community, or public cloud.