SECURITY GUIDANCE FOR CRITICAL AREAS OF FOCUS IN CLOUD COMPUTING V3.0 SECURITY GUIDANCE FOR CRITICAL AREAS OF FOCUS IN CLOUD COMPUTING V3.0 INTRODUCTION The guidance provided herein is the third version of the Cloud Security Alliance document, “Security Guidance for Critical Areas of Focus in Cloud Computing,” which was originally released in April 2009. The permanent archive locations for these documents are: http://www.cloudsecurityalliance.org/guidance/csaguide.v3.0.pdf (this document) http://www.cloudsecurityalliance.org/guidance/csaguide.v2.1.pdf (version 2 guidance) http://www.cloudsecurityalliance.org/guidance/csaguide.v1.0.pdf (version 1 guidance) In a departure from the second version of our guidance, each domain was assigned its own editor and peer reviewed by industry experts. The structure and numbering of the domains align with industry standards and best practices. We encourage the adoption of this guidance as a good operating practice in strategic management of cloud services. These white papers and their release schedule are located at: http://www.cloudsecurityalliance.org/guidance/ In another change from the second version, there are some updated domain names. We have these changes: Domain 3: Legal Issues: Contracts and Electronic Discovery and Domain 5: Information Management and Data Security. We now have added another domain, which is Domain 14: Security as a Service. © 2011 Cloud Security Alliance. All rights reserved. You may download, store, display on your computer, view, print, and link to the Cloud Security Alliance Guidance at http://www.cloudsecurityalliance.org/guidance/csaguide.v3.0.pdf subject to the following: (a) the Guidance may be used solely for your personal, informational, non-commercial use; (b) the Guidance may not be modified or altered in any way; (c) the Guidance may not be redistributed; and (d) the trademark, copyright or other notices may not be removed. You may quote portions of the Guidance as permitted by the Fair Use provisions of the United States Copyright Act, provided that you attribute the portions to the Cloud Security Alliance Guidance Version 3.0 (2011). ©2011 CLOUD SECURITY ALLIANCE | 1 SECURITY GUIDANCE FOR CRITICAL AREAS OF FOCUS IN CLOUD COMPUTING V3.0 TABLE OF CONTENTS Introduction ........................................................................................................................................................................... 1 Foreword ................................................................................................................................................................................ 3 Acknowledgments ................................................................................................................................................................. 4 Letter from the Editors .......................................................................................................................................................... 6 An Editorial Note on Risk ...................................................................................................................................................... 8 Section I. Cloud Architecture ............................................................................................................................................... 11 Domain 1: Cloud Computing Architectural Framework ....................................................................................................... 12 Section II. Governing in the Cloud ...................................................................................................................................... 29 Domain 2: Governance and Enterprise Risk Management .................................................................................................. 30 Domain 3: Legal Issues: Contracts and Electronic Discovery ............................................................................................... 35 Domain 4: Compliance and Audit Management .................................................................................................................. 45 Domain 5: Information Management and Data Security ..................................................................................................... 50 Domain 6: Interoperability and Portability .......................................................................................................................... 64 Section III. Operating in the Cloud ...................................................................................................................................... 73 Domain 7: Traditional Security, Business Continuity, and Disaster Recovery ..................................................................... 74 Domain 8: Data Center Operations ...................................................................................................................................... 89 Domain 9: Incident Response .............................................................................................................................................. 93 Domain 10: Application Security ........................................................................................................................................ 103 Domain 11: Encryption and Key Management .................................................................................................................. 129 Domain 12: Identity, Entitlement, and Access Management ............................................................................................ 136 Domain 13: Virtualization .................................................................................................................................................. 157 Domain 14: Security as a Service ....................................................................................................................................... 162 ©2011 CLOUD SECURITY ALLIANCE | 2 SECURITY GUIDANCE FOR CRITICAL AREAS OF FOCUS IN CLOUD COMPUTING V3.0 FOREWORD Welcome to the third version of the Cloud Security Alliance’s “Security Guidance for Critical Areas of Focus in Cloud Computing.” As cloud computing begins to mature, managing the opportunities and security challenges becomes crucial to business development. We humbly hope to provide you with both guidance and inspiration to support your business needs while managing new risks. The Cloud Security Alliance has delivered actionable, best practices based on previous versions of this guidance. As we continue to deliver tools to enable businesses to transition to cloud services while mitigating risk, this guidance will act as the compass for our future direction. In v3.0, you will find a collection of facts and opinions gathered from over seventy industry experts worldwide. We have compiled this information from a range of activities, including international chapters, partnerships, new research, and conference events geared towards furthering our mission. You can follow our activities at www.cloudsecurityalliance.org. The path to secure cloud computing is surely a long one, requiring the participation of a broad set of stakeholders on a global basis. However, we should happily recognize the progress we are seeing: new cloud security solutions are regularly appearing, enterprises are using our guidance to engage with cloud providers, and a healthy public dialogue over compliance and trust issues has erupted around the world. The most important victory we have achieved is that security professionals are vigorously engaged in securing the future, rather than simply protecting the present. Please stay engaged on this topic and continue to work with us to complete this important mission. Best Regards, Jerry Archer Dave Cullinane Nils Puhlmann Alan Boehme Paul Kurtz Jim Reavis The Cloud Security Alliance Board of Directors ©2011 CLOUD SECURITY ALLIANCE | 3 SECURITY GUIDANCE FOR CRITICAL AREAS OF FOCUS IN CLOUD COMPUTING V3.0 ACKNOWLEDGMENTS Domain Authors/Contributors Domain 1: Chris Hoff, Paul Simmonds Domain 2: Marlin Pohlman, Becky Swain, Laura Posey, Bhavesh Bhagat Domain 3: Francoise Gilbert, Pamela Jones Harbour, David Kessler, Sue Ross, Thomas Trappler Domain 4: Marlin Pohlman, Said Tabet Domain 5: Rich Mogull, Jesus Luna Domain 6: Aradhna Chetal, Balaji Ramamoorthy, Jim Peterson, Joe Wallace, Michele Drgon, Tushar Bhavsar Domain 7: Randolph Barr, Ram Kumar, Michael Machado, Marlin Pohlman Domain 8: Liam Lynch Domain 9: Michael Panico, Bernd Grobauer, Carlo Espiritu, Kathleen Moriarty, Lee Newcombe, Dominik Birk, Jeff Reed Domain 10: Aradhna Chetal, Balaji Ramamoorthy, John Kinsella, Josey V. George, Sundararajan N., Devesh Bhatt, Tushar Bhavsar Domain 11: Liam Lynch Domain 12: Paul Simmonds, Andrew Yeomans, Ian Dobson, John Arnold, Adrian Secombe, Peter Johnson, Shane Tully, Balaji Ramamorthy, Subra Kumaraswamy, Rajiv Mishra, Ulrich Lang, Jens Laundrup, Yvonne Wilson Domain 13: Dave Asprey, Richard Zhao, Kanchanna Ramasamy Balraj, Abhik Chaudhuri, Melvin M. Rodriguez Domain 14: Jens Laundrup, Marlin Pohlman, Kevin Fielder Peer Reviewers Valmiki Mukherjee, Bernd Jaeger, Ulrich Lang, Hassan Takabi, Pw Carey, Xavier Guerin, Troy D. Casey, James Beadel, Anton Chuvakin, Tushar Jain, M S Prasad, Damir Savanovic, Eiji Sasahara, Chad Woolf, Stefan Pettersson, M S Prasad, Nrupak Shah, Kimberley Laris, Henry St. Andre, Jim Peterson, Ariel Litvin, Tatsuya Kamimura, George Ferguson, Andrew Hay, Danielito Vizcayno, K.S. Abhiraj, Liam Lynch, Michael Marks, JP Morgenthal, Amol Godbole, Damu Kuttikrishnan, Rajiv Mishra, Dennis F. Poindexter, Neil Fryer, Andrea Bilobrk, Balaji Ramamoorthy, Damir Savanovic Editorial Team Archie Reed: Domains 3, 8, 9 ©2011 CLOUD SECURITY ALLIANCE | 4 SECURITY GUIDANCE FOR CRITICAL AREAS OF FOCUS IN CLOUD COMPUTING V3.0 Chris Rezek: Domains 2, 4, 5, 7, 13, 14 Paul Simmonds: Domains 1, 6, 10, 11, 12 CSA Staff Technical Writer/Editor: Amy L. Van Antwerp Graphic Designer: Kendall Scoboria Research Director: J.R. Santos ©2011 CLOUD SECURITY ALLIANCE | 5 SECURITY GUIDANCE FOR CRITICAL AREAS OF FOCUS IN CLOUD COMPUTING V3.0 LETTER FROM THE EDITORS Over the past three years, the Cloud Security Alliance has attracted around 120 corporate members and has a broad remit to address all aspects of cloud security, including compliance, global security-related legislation and regulation, identity management, and the challenge of monitoring and auditing security across a cloud-based IT supply chain. CSA is becoming the focal point for security standards globally, aligning multiple, disparate government policies on cloud security and putting forward standards for ratification by international standards bodies. CSA sees itself as a cloud security standards incubator, so its research projects use rapid development techniques to produce fast results. To this end, the CSA Guidance editorial team is proud to present the third version of its flagship “Security Guidance for Critical Areas of Focus in Cloud Computing.” This work is a set of best security practices CSA has put together for 14 domains involved in governing or operating the cloud (Cloud Architecture, Governance and Enterprise Risk Management, Legal: Contracts and Electronic Discovery, Compliance and Audit, Information Management and Data Security, Portability and Interoperability, Traditional Security, Business Continuity and Disaster Recovery, Data Center Operations, Incident Response, Notification and Remediation, Application Security, Encryption and Key Management, Identity and Access Management, Virtualization, and Security as a Service). CSA guidance in its third edition seeks to establish a stable, secure baseline for cloud operations. This effort provides a practical, actionable road map to managers wanting to adopt the cloud paradigm safely and securely. Domains have been rewritten to emphasize security, stability, and privacy, ensuring corporate privacy in a multi-tenant environment. Over the past two years, version 2.1 of the guidance has served as the foundation for research in multiple areas of cloud security. Deliverables now in use from the TCI Architecture to the GRC Stack were inspired by previous versions of the guidance, and it is our hope that this version will be no different. The guidance serves as a high level primer for chief executives, consumers, and implementers wishing to adopt cloud services as an alternative or supplement to traditional infrastructure. However, the guidance is designed with innovation in mind. Those with an entrepreneurial mindset should read this work with an eye toward the inferred services and approaches many of the authors have included in the domain creation. Investors and corporate decision makers will also find this work of interest, as it serves as a roadmap for innovation and development already in place in companies throughout the world. Security practitioners and educators will find elements of this book both authoritative and thought provoking, and as the industry evolves, the value the authors have included should prove influential and timely. In the third edition, the guidance assumes a structural maturity in parallel with multinational cloud standards development in both structure and content. Version 3.0 extends the content included in previous versions with practical recommendations and requirements that can be measured and audited. Please note that different interpretations of the term "requirements" exist, which we use throughout the document. Our guidance does not represent a statutory obligation, but "requirements" was chosen to represent guidance appropriate for virtually all use cases we could envision, and also aligns our guidance with similar well-accepted documents. CSA industry expert authors have endeavored to present a working product that is measured and balanced between the interests of cloud providers and tenants. Controls focus on the preservation of tenant data ownership integrity while embracing the concept of a shared physical infrastructure. Guidance Version 3.0 incorporates the highly dynamic nature of cloud computing, industry learning curve, and new developments within other research projects such as Cloud Controls Matrix, Consensus Assessments Initiative, Trusted Cloud Initiative, and GRC Stack Initiative and ties in the various CSA activities into one comprehensive C-level best practice. The Security Guidance v3.0 will serve as the gateway to emerging standards being ©2011 CLOUD SECURITY ALLIANCE | 6 SECURITY GUIDANCE FOR CRITICAL AREAS OF FOCUS IN CLOUD COMPUTING V3.0 developed in the world’s standards organization and is designed to serve as an executive-level primer to any organization seeking a secure, stable transition to hosting their business operations in the cloud. On behalf of the Cloud Security Alliance, we would like to thank each and every volunteer for their time and effort in the development and editing of this new release of our flagship guidance document. While we believe this is our best, most widely reviewed work to date, the topic is still evolving and although our foremost intent is to guide, we also intend to inspire the readers to become involved in improving and commenting on the direction those composing the body of work have outlined. We humbly and respectfully submit this effort to the industry and await the most important component of any dialog, your opinion. We are eager to hear your feedback regarding this updated guidance. If you found this guidance helpful or would like to see it improved, please consider joining the Cloud Security Alliance as a member or contributor. Best Regards, Paul Simmonds Chris Rezek Archie Reed Security Guidance v3.0 Editors ©2011 CLOUD SECURITY ALLIANCE | 7 SECURITY GUIDANCE FOR CRITICAL AREAS OF FOCUS IN CLOUD COMPUTING V3.0 AN EDITORIAL NOTE ON RISK Throughout this Guidance we make extensive recommendations on reducing your risk when adopting cloud computing, but not all the recommendations are necessary or even realistic for all cloud deployments. As we compiled information from the different working groups during the editorial process, we quickly realized there simply wasn’t enough space to provide fully nuanced recommendations for all possible risk scenarios. Just as a critical application might be too important to move to a public cloud provider, there might be little or no reason to apply extensive security controls to low-value data migrating to cloud-based storage. With so many different cloud deployment options — including the SPI service models (SPI refers to Software as a Service, Platform as a Service, or Infrastructure as a Service, explained in depth in Domain 1); public vs. private deployments, internal vs. external hosting, and various hybrid permutations — no list of security controls can cover all circumstances. As with any security area, organizations should adopt a risk-based approach to moving to the cloud and selecting security options. The following is a simple framework to help evaluate initial cloud risks and inform security decisions. This process is not a full risk assessment framework, nor a methodology for determining all your security requirements. It’s a quick method for evaluating your tolerance for moving an asset to various cloud computing models. Identify the Asset for the Cloud Deployment At the simplest, assets supported by the cloud fall into two general categories: 1. Data 2. Applications/Functions/Processes We are either moving information into the cloud, or transactions/processing (from partial functions all the way up to full applications). With cloud computing our data and applications don’t need to reside in the same location, and we can choose to shift only parts of functions to the cloud. For example, we can host our application and data in our own data center, while still outsourcing a portion of its functionality to the cloud through a Platform as a Service. The first step in evaluating risk for the cloud is to determine exactly what data or function is being considered for the cloud. This should include potential uses of the asset once it moves to the cloud to account for scope creep. Data and transaction volumes are often higher than expected. Evaluate the Asset The next step is to determine how important the data or function is to the organization. You don’t need to perform a detailed valuation exercise unless your organization has a process for that, but you do need at least a rough assessment of how sensitive an asset is, and how important an application/function/process is. ©2011 CLOUD SECURITY ALLIANCE | 8 SECURITY GUIDANCE FOR CRITICAL AREAS OF FOCUS IN CLOUD COMPUTING V3.0 For each asset, ask the following questions: 1. How would we be harmed if the asset became widely public and widely distributed? 2. How would we be harmed if an employee of our cloud provider accessed the asset? 3. How would we be harmed if the process or function were manipulated by an outsider? 4. How would we be harmed if the process or function failed to provide expected results? 5. How would we be harmed if the information/data were unexpectedly changed? 6. How would we be harmed if the asset were unavailable for a period of time? Essentially we are assessing confidentiality, integrity, and availability requirements for the asset; and how the risk changes if all or part of the asset is handled in the cloud. It’s very similar to assessing a potential outsourcing project, except that with cloud computing we have a wider array of deployment options, including internal models. Map the Asset to Potential Cloud Deployment Models Now we should have an understanding of the asset’s importance. Our next step is to determine which deployment models we are comfortable with. Before we start looking at potential providers, we should know if we can accept the risks implicit to the various deployment models: private, public, community, or hybrid; and hosting scenarios: internal, external, or combined. For the asset, determine if you are willing to accept the following options: 1. Public. 2. Private, internal/on-premises. 3. Private, external (including dedicated or shared infrastructure). 4. Community; taking into account the hosting location, potential service provider, and identification of other community members. 5. Hybrid. To effectively evaluate a potential hybrid deployment, you must have in mind at least a rough architecture of where components, functions, and data will reside. At this stage you should have a good idea of your comfort level for transitioning to the cloud, and which deployment models and locations fit your security and risk requirements. Evaluate Potential Cloud Service Models and Providers In this step focus on the degree of control you’ll have at each SPI tier to implement any required risk management. If you are evaluating a specific offering, at this point you might switch to a fuller risk assessment. ©2011 CLOUD SECURITY ALLIANCE | 9