Introduction to SOA, Cloud Computing, and Secure Cloud Computing

1. Introduction to SOA, Cloud Computing, and Secure Cloud Computing Bhavani Thuraisingham The University of Texas at Dallas September 18, 2015

2. Objective and Scope • The objective of this course is to provide an overview of the significant developments in SOA and Web Services Security Standards as well as directions for future developments • Current work on SOA security is focusing mainly on access control as well as confidentiality and integrity. • Solutions proposed for systems to address intrusion detection, denial of service and infrastructure attacks, insider threat analysis including data mining techniques for security applications are beyond the scope of this course.

3. Outline • SOA and Web services: Overview • SOA and Web services security: Overview • WS-Security and WS-* Security

4. Service Oriented Architecture (SOA) http://en.wikipedia.org/wiki/Service-oriented_architecture • Service Oriented Architecture (SOA) is an architectural style that guides all aspects of creating and using business processes, packaged as services, throughout their lifecycle, as well as defining and provisioning the IT infrastructure that allows different applications to exchange data and participate in business processes loosely coupled from the operating systems and programming languages underlying those applications • SOA represents a model in which functionality is decomposed into distinct units (services), which can be distributed over a network and can be combined together and reused to create business applications • These services communicate with each other by passing data from one service to another, or by coordinating an activity between two or more services. • SOA concepts makes software development flexible and extensible • Service oriented analysis is becoming key to modeling and analyzing software • The concepts of Service Oriented Architecture are often seen as built upon, and the evolution of, the older concepts of distributed computing and modular programming • While object-orientation views the world as a collection of objects, service orientation views the world as a collection of services • SOA is technology independent; however it is commonly realized using web services

5. Web service definition “A Web Service is a software system designed to support interoperable machine-to-machine interaction over a network. It has an interface described in a machine-processable format (specifically WSDL). Other systems interact with the Web service in a manner prescribed by its description using SOAP messages, typically conveyed using HTTP with an XML serialization in conjunction with other Web-related standards.” Source: http://www.w3.org/TR/ws-arch/

6. Request Response Publish Services Query UDDI Answer Service requestor Service providers SOA

7. Web Services (WS) Framework • An abstract (vendor neutral) existence defined by standards organizations and implemented by (proprietary) technology platforms • Core building blocks that include web sercices, service descriptions and messages • A communication agreement centered around service descriptions and WSDL • A messaging framework comprised of SOAP technology concepts • A service description registration and discovery architecture sometimes realized through UDDI • A well defined architecture that supports messaging patterns and compositions • A second generation of web services extensions (also known as WS-* specifications) continually broadening its underlying feature-set • Concepts in WS-* include: Message Exchange Patterns (MEP), Service Activity, Coordination, Atomic Transaction, Business Activities, Orchestration (WS-BPEL), Choreography (WS-CDL) • Reference: Service Oriented Architecture, Thomas Erl, Prentice Hall, 2005

8. Standardization bodies related to Web Services

9. SOA Security • Our approach is to implement SOA through web services; therefore SOA security essentially is about web services security • Three core specifications • WS-Security, XML-Signature, XML-Encryption • WS*-Security is the second generation of technologies for SOA security • Single sign-on (SSO) is a form of centralized security mechanism that complements the WS-Security extensions • Related specifications for SOA security • WS-Security, WS-SecurityPolicy, WS-Trust, WS-SecureConversation, WS-Federation, XACML, Extensibe Rights Markup Language, XML Key Management, XML, Signature, SAML, .NET Passport, Secure Socket Layer, WS-I Basic Security Profile

10. Basic Components of SOA Security • Identification • For service requestor to acces a secure service provider it must first provide information that expresses its origin or owner. This is referred to as making a claim • Authentiaction • A message being delivered to a receipient must prove that the message is in fact from the sender that it claims • Authorization • Once authenticated, the receipient of a message may need to determine what the requestor is alowed to do • Singe sign on • It is supported by SAML, .NET Passport and XACML • Confidentiality and Integrity • Confidentiality is concerned with protecting the privacy of the message content, Integrity ensures that the message has not been altered • Transport level and Message level security • Transport level securiy is provided by SSL (securing HTTP), message level confidentiality and integrity are provied by XML-Encryption and XML-Signature.

11. Web Services Security: Requirements and Standards • Securing Web services mainly requires to: • provide facilities for securing the integrity and confidentiality of the messages and • ensure that the service acts only on requests in messages that express the claims required by policies • Role of Standards • Providing a Web Services Security Framework that is an integral part of the Web Services Architecture • The framework is a layered and composable set of standard specifications

12. WS-* security Standards framework

13. WS-* security standards implementations • Microsoft .NET Framework 2.0 / WSE3.0 • WS-Security (OASIS 2004 standard), WS-Policy, WS-SecurityPolicy, WS-Trust, WS-SecureConversation and WS-Addressing • SUN Web Services Interoperability Technology (WSIT) • IBM WebSphere • Open Software: The Apache Software Foundation Web Services Project (http://ws.apache.org/)

14. XML Encryption XML Encryption Syntax and Processing 10 December 2002 Status W3C Recommendation Core standard Goals: • provide confidentiality for applications that exchange structured data by • Representing in a standard way digitally encrypted resources • separating encryption information from encrypted data, and supporting reference mechanisms for addressing encryption information from encrypted data sections and vice-versa • providing a mechanism for conveying encryption key information to a recipient • providing for the encryption of a part or totality of an XML document

15. XML Signature XML-Signature Syntax and Processing 12 February 2002 Status: W3C Recommendation Core standard: XML Signature is a building block for many web services security standards (e.g. XKMS and WS-Security) Goals: • represent a digital signature as an XML element • Processing rules for creating this XML element • The signed data items can be of different types and granularity (XML documents, XML Elements, files containing any type of digital data)

16. Securing SOAP messagesWeb Services Security: SOAP Message Security 1.1 (WS-Security 2004)Status: Approved OASIS Standard Specification 1 February 2006 • Goals: • Provide single SOAP message integrity and confidentiality • Using existing digital signature, encryption, and security token mechanisms • Provide mechanisms for associating security tokens with message content (header and body blocks) • Extensibility (i.e. support multiple security token format) the recipient can trust the content of the message and its sender Security Token - a representation of security-related information (e.g. X.509 certificate, Kerberos tickets and authenticators, mobile device security tokens from SIM cards, username, etc.). Signed Security Token - a security token that contains a set of related claims (assertions) cryptographically endorsed by an issuer. Examples: X.509 certificates and Kerberos tickets.

17. What is WS-Security? • WS-Security enhances SOAP messaging to provide quality of protection through: • message integrity, • message confidentiality, and • single message authentication. • These mechanisms can be used to accommodate a wide variety of security models and encryption technologies. • WS-Security also provides a general-purpose, extensible mechanism for associating security tokens with messages: • No specific type of security token is required • support for multiple security token formats • WS-Security describes how to encode binary security tokens( X.509 certificates and Kerberos tickets)

18. WS-Policy • Web Services Policy 1.2 - Framework (WS-Policy) W3C Member Submission 25 April 2006 • Status: public draft release for review and evaluation only • Main goal: The WS-Policy and WS-PolicyAttachment aim to offer mechanisms to represent the capabilities and requirements of Web services as Policies • Policy view in WS-Policy: • A policy is used to convey conditions on an interaction between two Web service endpoints. • The provider of a Web service exposes a policy to convey conditions under which it provides the service. • A requester might use this policy to decide whether or not to use the service.

19. XACML • eXtensible Access Control Markup Language 2 (XACML) Version 2.0 OASIS Standard, 1 Feb 2005 • Status: approved OASIS Standard within the OASIS Access 12 Control TC. • XACML is a general-purpose access control policy language for managing access to resources • It describes both a policy language and an access control decision request/response language • Fine access control grained control • Access control based on subject and object attributes • Consistent with and building upon SAML

20. XACML – Key Aspects • General-purpose authorization policy model and XML-based specification language • XACML is independent of SAML specification • Triple-based policy syntax: <Object, Subject, Action> • Negative authorization is supported • Input/output to the XACML policy processor is clearly defined as XACML context data structure • Input data is referred by XACML-specific attribute designator as well as XPath expression • Extension points: function, identifier, data type, rule-combining algorithm, policy-combining algorithm, etc. • A policy consists of multiple rules • A set of policies is combined by a higher level policy (PolicySet element)

21. XACML data flow model Source: oasis-access_control-xacml-2.0-core-spec-os

22. Policy Enforcement Point (PEP) Policy Decision Point (PDP) Policy Access Point (PAP) Policy Information Point (PIP) XACML Protocol XACML Request/ Response

23. XACML Protocol • When a client makes a resource request upon a server, the PEP is charged with AC • In order to enforce AC policies, the PEP will formalize the attributes describing the requester at the PIP and delegate the authorization decision to the PDP • Applicable policies are located in a policy store, managed by the PAP, and evaluated at the PDP, which then returns the authorization decision • Using this information, the PEP can deliver the appropriate response to the client • XACML Request • Subject • Object • Action • XACML Response • Permit • Permit with Obligations • Deny • NotApplicable (the PDP cannot locate a policy whose target matches the required resource) • Indeterminate (an error occurred or some required value was missing)

24. XACML Protocol • The Policy Administration Point (PAP) creates security policies and stores these policies in the appropriate repository. • The Policy Enforcement Point (PEP) performs access control by making decision requests and enforcing authorization decisions. • The Policy Information Point (PIP) serves as the source of attribute values, or the data required for policy evaluation. • The Policy Decision Point (PDP) evaluates the applicable policy and renders an authorization decision. Note: The PEP and PDP might both be contained within the same application, or might be distributed across different servers

25. XACML policy • A Policy has four main components: • A target • A rule-combining algorithm identifier • A set of rules • Obligations • The Rule is the elementary unit of a policy • Main components of a rule: • A target • An effect: permit or deny • A condition • Policy Language • A policy target specifies a set of: • Resources • Subjects • Actions • Environment • to which it applies

26. Security Assertion Markup Language (SAML) • Developed by the OASIS XML-Based Security Services Technical Committee (SSTC) • Status: SAML V2.0 OASIS Standard specification set was approved on 15 March 2005 • Main goal: authentication and authorization • promote interoperability between disparate authentication and authorization systems • How: • defining an XML-based framework for communicating security and identity information (e.g., authentication, entitlements, and attribute) between computing entities • using available different security infrastructures (e.g., PKI, Kerberos, LDAP, etc)

27. SAML basic concepts • Assertions: The core concept • SAML Authority: a system entity that makes SAML assertions (also called Identity Provider – IdP – and Asserting Party) • Service Provider: a system entity making use of SAML assertions • Relying Party: a system entity that uses received assertions (named also SAML requester) • SAML Bindings: Bindings describe exactly how the SAML protocol maps onto the transport protocols.

28. SAML assertions • An assertion is constituted by one or more statements made by a SAML authority • Different kinds of assertion statement that can be created by a SAML authority: • Authentication: The specified subject was authenticated by a particular means at a particular time. • Attribute: The specified subject is associated with the supplied attributes. • Authorization decision statements: the specified subject is entitled to do a specified action “Martino authenticated with a password at 9:00am” “Bill is an account manager with a $1000 spending limit per one-day travel” “John Doe” is permitted to buy a specified item

29. SAML entities SAML Authority makes SAML assertions SAML Requester a system entity that uses received assertions Service Providersa system entity making use of SAML assertions

30. SAML and XACML Source: Security Assertion Markup Language (SAML) V2.0 Technical Overview Working Draft 08, 12 September 2005

31. SAML & Federated Identity • SAML addresses one key aspect of identity management: how identity information can be communicated from one domain to another • SAML 2.0 will be the basis on which Liberty Alliance builds additional federated identity applications (such as web service-enabled permissions-based attribute sharing).

32. Cloud Computing • Cloud computing is the delivery of computing as a service rather than a product, whereby shared resources, software, and information are provided to computers and other devices as a metered service over a network • Cloud computing provides computation, software, data access, and storage resources without requiring cloud users to know the location and other details of the computing infrastructure. • End users access cloud based applications through a web browser or a light weight desktop or mobile app while the business software and data are stored on servers at a remote location. • Cloud application providers strive to give the same or better service and performance as if the software programs were installed locally on end-user computers. • At the foundation of cloud computing is the broader concept of infrastructure convergence and shared services.

33. Service Models • Cloud computing providers offer their services according to three fundamental models Infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS) where IaaS is the most basic and each higher model abstracts from the details of the lower models. • Infrastructure as a Service (IaaS) • In this most basic cloud service model, cloud providers offer computers – as physical or more often as virtual machines; raw (block) storage, firewalls, load balancers, and networks. • IaaS providers supply these resources on demand from their large pools installed in data centers.. • To deploy their applications, cloud users then install operating system images on the machines as well as their application software. • In this model, it is the cloud user who is responsible for patching and maintaining the operating systems and application software. • Platform as a Service (PaaS) • In the PaaS model, cloud providers deliver a computing platform and/or solution stack typically including operating system, programming language execution environment, database, and web server. • Application developers can develop and run their software solutions on a cloud platform without the cost and complexity of buying and managing the underlying hardware and software layers. • Software as a Service (SaaS) • In this model, cloud providers install and operate application software in the cloud and cloud users access the software from cloud clients

34. Deployment Models • Public cloud • A public cloud is one based on the standard cloud computing model, in which a service provider makes resources, such as applications and storage, available to the general public over the Internet. • Public cloud services may be free or offered on a pay-per-usage model. • Community cloud • Community cloud shares infrastructure between several organizations from a specific community with common concerns (security, compliance, jurisdiction, etc.), whether managed internally or by a third-party and hosted internally or externally. • The costs are spread over fewer users than a public cloud (but more than a private cloud), so only some of the cost savings potential of cloud computing are realized. • Hybrid cloud • Hybrid cloud is a composition of two or more clouds (private, community or public) that remain unique entities but are bound together, offering the benefits of multiple deployment models. • It can also be defined as multiple cloud systems that are connected in a way that allows programs and data to be moved easily from one deployment system to another. • Private cloud • Private cloud is infrastructure operated solely for a single organization, whether managed internally or by a third-party and hosted internally or externally,

35. Issues • Privacy • Using a cloud service provider (CSP) can complicate privacy of data because of the extent to which virtualization for cloud processing (virtual machines) and cloud storage are used to implement cloud services. • Security • The effectiveness and efficiency of traditional protection mechanisms are being reconsidered as the characteristics of this innovative deployment model can differ widely from those of traditional architectures • Compliance • In order to obtain compliance with regulations including FISMA, HIPAA, and SOX in the United States, the Data Protection Directive in the EU and the credit card industry's PCI DSS, users may have to adopt community or hybrid deployment modes that are typically more expensive and may offer restricted benefits. • Legal • Certain legal issues arise; everything from trademark infringement, security concerns to the sharing of propriety data resources.

36. Secure Cloud Computing • Cloud computing security refers to a broad set of policies, technologies, and controls deployed to protect data, applications, and the associated infrastructure of cloud computing. • Cloud security is not to be confused with security software offerings that are "cloud-based" (a.k.a. security-as-a-service). • There are a number of security issues/concerns associated with cloud computing but these issues fall into two broad categories: • Security issues faced by cloud providers (organizations providing Software-, Platform-, or Infrastructure-as-a-Service via the cloud) • Security issues faced by their customers. In most cases, the provider must ensure that their infrastructure is secure and that their clients’ data and applications are protected while the customer must ensure that the provider has taken the proper security measures to protect their information • The extensive use of virtualization in implementing cloud infrastructure brings unique security concerns for customers or tenants of a public cloud service. • Virtualization alters the relationship between the OS and underlying hardware - be it computing, storage or even networking. • This introduces an additional layer - virtualization - that itself must be properly configured, managed and secured. • Specific concerns include the potential to compromise the virtualization software, or "hypervisor". While these concerns are largely theoretical, they do exist

37. Security and Privacy • Security and privacy • In order to ensure that data is secure (that it cannot be accessed by unauthorized users or simply lost) and that data privacy is maintained, cloud providers attend to the following areas: • Data protection  • To be considered protected, data from one customer must be properly segregated from that of another; it must be stored securely when “at rest” and it must be able to move securely from one location to another. • Cloud providers have systems in place to prevent data leaks or access by third parties. Proper separation of duties should ensure that auditing or monitoring cannot be defeated, even by privileged users at the cloud provider • Physical Control  • Physical control of the Private Cloud equipment is more secure than having the equipment off site and under someone else’s control. • Having the ability to visually inspect the data links and access ports is required in order to ensure data links are not compromised. • Identity management  • Every enterprise will have its own identity management system to control access to information and computing resources. • Cloud providers either integrate the customer’s identity management system into their own infrastructure, using federation or SSO technology, or provide an identity management solution of their own.

38. Security and Privacy • Physical and personnel security  • Providers ensure that physical machines are adequately secure and that access to these machines as well as all relevant customer data is not only restricted but that access is documented. • Availability  • Cloud providers assure customers that they will have regular and predictable access to their data and applications. • Application security  • Cloud providers ensure that applications available as a service via the cloud are secure by implementing testing and acceptance procedures for outsourced or packaged application code. It also requires application security measures (application-level firewalls) be in place in the production environment. • Privacy  • Finally, providers ensure that all critical data (credit card numbers, for example) are masked and that only authorized users have access to data in its entirety. • Moreover, digital identities and credentials must be protected as should any data that the provider collects or produces about customer activity in the cloud. • Legal issues  • In addition, providers and customers must consider legal issues, such as Contracts and E-Discovery, and the related laws, which may vary by country

39. Compliance • Compliance • Numerous regulations pertain to the storage and use of data, including Payment Card Industry Data Security Standard (PCI DSS), the Health Insurance Portability and Accountability Act (HIPAA), the Sarbanes-Oxley Act, among others. • Many of these regulations require regular reporting and audit trails. • Cloud providers must enable their customers to comply appropriately with these regulations. • Business continuity and data recovery • Cloud providers have business continuity and data recovery plans in place to ensure that service can be maintained in case of a disaster or an emergency and that any data loss will be recovered. • These plans are shared with and reviewed by their customers. • Logs and audit trails • In addition to producing logs and audit trails, cloud providers work with their customers to ensure that these logs and audit trails are properly secured, maintained for as long as the customer requires, and are accessible for the purposes of forensic investigation • Unique compliance requirements • In addition to the requirements to which customers are subject, the data centers maintained by cloud providers may also be subject to compliance requirements. • Using a cloud service provider (CSP) can lead to additional security concerns around data jurisdiction since customer or tenant data may not remain on the same system, or in the same data center or even within the same provider's cloud.

40. Compliance • Legal and contractual issues • Aside from the security and compliance issues enumerated above, cloud providers and their customers will negotiate terms around liability (stipulating how incidents involving data loss or compromise will be resolved, for example), intellectual property, and end-of-service (when data and applications are ultimately returned to the customer. • Public records • Legal issues may also include records-keeping requirements in the public sector, where many agencies are required by law to retain and make available electronic records in a specific fashion. • This may be determined by legislation, or law may require agencies to conform to the rules and practices set by a records-keeping agency. • Public agencies using cloud computing and storage must take these concerns into account.

41. Summary Points • SOA concept based on service orientation is now a significant method for software development and promotes extensibility and flexibility; Service oriented analysis has now become a standard way to model software • Web Services is just one way to realize SOA • Security for SOA is crucial as SOA is being used in numerous sectors; since web services realize SOA, web services security is critical • SOA and SOA Security Standards are being developed by W3C and OASIS; WS-Security, WS*-Security Framework, and XACML are some of the key standards • SOA and Web Services are at the heart of Cloud Computing