Computer Science and Engineering 1 Service-Oriented Architecture Security 2.

Reading 1.New: Security Fundamentals for Web Services, Microsoft patterns and practices, Computer Science and Engineering 2

3 SOA Security Components 1.Software-level (single service) security 2.Business-level (service composition) security 3.Network-level security

Computer Science and Engineering 4 Network-Level Security Authentication and identification Access Control middlewareMessaging middleware –Communication security –End point security Protocol assurance Security PatternsSecurity Patterns

Service-level Patterns Exception Shielding Message Validation Trusted Subsystem Service Perimeter Guard Computer Science and Engineering 5

Exception Shielding Computer Science and Engineering 6

Message Validator Computer Science and Engineering 7

8 Trusted Subsystem GoalGoal: prevent customers from circumventing a service and directly accessing the resources of the service ProblemProblem: –Customer may perform incorrect modifications –May lead to undesirable forms of implementation coupling SolutionSolution: service is designed to use own credentials for authentication with backend resources

Trusted Subsystem Computer Science and Engineering 9

10 Perimeter Guard GoalGoal: protect internal resources from users that remotely access internal computers ProblemProblem: –External attacker may gain access to services running within a private network, and thus to the resources within the private network SolutionSolution: establish an intermediate service at the perimeter of the private network as a secure contact point

Service Perimeter Guard Computer Science and Engineering 11

Service Interaction Patterns Data Confidentiality Data Origin Authentication Direct Authentication Brokered Authentication Computer Science and Engineering 12

Data Confidentiality Computer Science and Engineering 13 Symmetric keyPublic key

Data Origin Authentication Computer Science and Engineering 14 Symmetric keyPublic key

Direct Authentication Computer Science and Engineering 15

Single Sign-On Authentication of a user within multiple systems: use Digital Certificates and private keys Reduces security administration Services can pass requester’s identity to other services

Brokered Authentication Computer Science and Engineering 17

Brokered Alternatives Computer Science and Engineering 18 Security Token ServiceX.509 Digital Certificate

Computer Science and Engineering 19 Service-Composition Security Ongoing activitiesOngoing activities: –Business process execution across heterogeneous domains –Identity management –Trust management Upcoming research areasUpcoming research areas: –Web Services Composition –Web Service Transactions –Service-Level Dependencies

Computer Science and Engineering 20 Web Services Composition Create complex applications on the fly from individual services BPEL4WS, WSBPEL How to express security and reliability needs? How to verify that these needs are satisfied? How to resolve conflict between business needs and security requirements?

Computer Science and Engineering 21 Web Services Transactions Traditional database transaction managements vs. SOA application needs How can we evaluate correct execution? ACID properties? Serializability? WS transaction framework: –Atomic (short-term) transactions –Business activity (long-term) transac –Business activity (long-term) transactions What are the security implications of WS transactions?

Computer Science and Engineering 22 Service-Level Dependencies Old threats reappearing in new context: deadlocks, denial-of-service, network flooding, etc. How to detect and prevent the occurrence of these threats? In composition, independently developed services are dependent on each other No information about internal processing of the workflow components

MLS SOA MLS: control information flow –Permitted flow: from low level to high level Revisit read/write operations –Subject reads object: info flow from object to subject –Subject writes object: info flow from subject to object WS communication: message transfer (write operation) Computer Science and Engineering 23

MLS Messages Metadata: represent proper classification Communication from High to Low services: message must be de-classified How can we achieve it? –Manual classification –Automated classification – TRUST? Computer Science and Engineering 24

MLS Service Interactions Over multiple domains Input/output messages Service broker: –Discover services –Enforces flow control: up-classify/down-classify data Computer Science and Engineering 25

Metadata management Data classification –Confidentiality –Integrity –Data access policy {s, f, d, c} s service f in/out d data classification level c conditions Computer Science and Engineering 26

Computer Science and Engineering 27 New Approaches to Improve Security and Reliability Develop criteria to evaluate correctness of composite application execution –E.g., WS transactions: compensation-based transactions Increase reliability using redundant services Offer security as service Develop defense models using distributed and collaborative components –E.g., detect malicious behavior based on collaborative nodes, verify execution correctness by comparing outcome of different services, deploy intelligent software decoy, etc.

Computer Science and Engineering 28 Conclusion and Future Work All aspects of SOA security must be addressed Standards are not enough to provide security! New security concepts applicable to SOA environment must be developed Security must be incorporated during the system development process collaboration SOA developers, business experts, and security professionalsRequires collaboration among SOA developers, business experts, and security professionals