# Patent

## Title
System and method for bridging identities in a service oriented architectureprofiling

## Abstract

A system for bridging user identities between at least a first and a second security domain, including a bridge associated with the first security domain for intercepting messages for service in the second domain from users in the first domain. The bridge authenticates the user identities against a local authentication source by using an established key relationship and binds a security token with the message. A gateway is associated with the second domain for gating inbound access and outbound communication with a service in the second domain and for receiving the authenticated message and verifying the authenticity of the security token by using a certificate of the trusted authentication source and authorizing access to the service upon confirmation of the authorization, such that the authorization is independent of the identity of the user.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 60/613,618 filed Sep. 28, 2004 and is a continuation of U.S. application Ser. No. 11/236,567 filed Sep. 28, 2005, which is a continuation-in-part of U.S. application Ser. No. 10/952,787 filed Sep. 30, 2004, all of which are incorporated herein by reference In their entirety.


FIELD OF THE INVENTION
The invention relates to the field of distributed computing in a client-server environment, and more particularly to a system and method for efficiently bridging identities across secure Web service domains.
BACKGROUND
Web services (generally XML-based) are a powerful vehicle for reusing shared application logic across diverse business processes as shown schematically in FIG. 10. These processes often need to traverse multiple departments, business units, and partners; each residing in separate security domains with independent preferences, capabilities, and requirements. As a consequence, serious communication, propagation, and processing problems arise as each independent security domain attempts to share Web services and applications. This problem—known as a “federation” problem—complicates and restricts the widespread implementation of Web services.
The fundamental challenge in the federation problem is a two-fold communication issue: First, how does an application in one security domain determine access rights for the identities coming from another security domain, and second, how does that same application determine those access rights without first knowing which identities are entitled to access the originating application? This flexible concept of identity, wherein users originating from one enterprise can authenticate at a second enterprise is known as “identity federation”.
Several new technologies and standards have been proposed to address the identity federation problem for the Web. However, the problem for Web services has been unresolved. In order to reach their potential in the modern extended enterprise, Web services must be able to effectively bridge application identities across diverse security domains.
One barrier to a solution to the identity federation problem is the proliferation of Identity Silos (an Identity Silo is a locally created and accessed identity store containing usernames and passwords that which typically cannot be re-used by another application for authentication and authorisation and provide no means to synchronize with another identity store) creates significant hurdles to the successful integration of applications residing in different security domains. This is equally true if the integration is based on Web services technology.
For consistent management, identities are typically stored in the same security domain as the application. An identity may represent another application, a human user, or a group of users and consist of elements such as common name, fully qualified name, group, role, certificate, and security clearance. During the authentication and authorization process, the exact elements in an identity are matched to the functional requirements of the applications or Web services served by the identity provider.
If a legitimate user, application, or Web service authenticates against a corresponding identity provider in one identity silo, their identity or any evidence of the authentication may have no relevance when requesting access to another application or Web service in another identity silo inside or outside the enterprise. In this case, the integration is broken and the authorization in one silo will fail even though the authentication succeeded in another silo. For Web services, this problem is compounded because most interactions happen between applications and no practical user intervention is possible.
Attempts to integrate disparate identity systems have traditionally used one or more of the technical approaches. These traditional approaches include; custom hard coding of rules and translators that map, transform, or otherwise manipulate identities exchanged between two silos; identity consolidation which maps identities associated with one authentication source to a single consolidated identity for authorization purposes; and directory synchronization which addresses some of the shortcomings of consolidation by replicating some or all of any remote identities into a separate store. While each approach provides part of the solution, each also has fundamental shortcomings that result in unwanted and risky side effects and are generally only effective in within a single administrative zone with a small number of identity stores.
Another common approach is the Single Sign-On (SSO) that provides single login access to a variety of back-end systems through Web portals and other gateway applications. A given entity signs on once and is granted the correct access and entitlements on multiple systems through some form of opaque cookie or token. Scaling SSO systems to encompass a broader spectrum of integration scenarios, however, can be challenging.
The SSO model does not eliminate the proliferation of disparate user IDs and passwords; it simply masks this issue for some pre-defined processes. Local applications are still responsible for authorizing users and determining what to do with the authentication token. This requires pre-negotiation of roles and entitlements and considerable amounts of custom code to process or map the incoming identities.
In the Web environment, most SSO products use cookies as evidence of authentication. This works well for human users signing into a Web browser page, but does not translate well between applications or in Web services integrations where there is no equivalent to a browser application. In both of these situations, the deployment of custom code or platform-specific agents is required to properly interpret and verify the cookies.
To address this problem, several SSO products now incorporate standards based tokens that offer more flexibility than proprietary cookies. An example is SAML (Security Assertion Markup Language), which defines an XML framework for exchanging authentication and authorization information between enterprises or web sites. The SAML specification itself does not define any new authentication technologies or approaches or address privacy or security policies. SAML forms the basis for many Web-based SSO systems and has proven interoperability between major vendors. Other standards activities such as WS-Federation standard are focused on strategically extending applications and Web services beyond a security domain firewall for Web services-based integrations.
Typically, the originating identity and some form of evidence of that identity's successful authentication are contained in a SAML assertion. Systems can pass these SAML tokens both within and across the firewall to a corresponding SAML “receiver” to receive, process, and verify the token. This approach—sometimes referred to as “Federated SSO” or “Federated Identity”—requires that exact security protocol for the token. If not protected in some manner, the same token can be used for subsequent replay attacks.
SSO systems still require considerable pre-negotiation of identity context between silos as well as the code to support proper authorization within this context. The introduction of SAML does provide a potentially powerful mechanism for exchanging both identity and evidence of authentication, but still requires significant infrastructure to securely exchange tokens, validate their authenticity, and correctly authorize users. This can lead to an expensive and time-consuming Web services implementation process even if an SSO system is already in place for an existing Web portal application.
The majority of today's identity-related integration issues are due to integrations of a moderate number of applications or users to address the specific business needs of an organization. The goal of these integrations is to bridge identity silos, not to deploy a complex infrastructure designed to federate identity to thousands of possible applications.
Identities and related management policies are constantly in flux due to both ordinary and extraordinary changes in operational, business, and regulatory needs. Any solution must be able to adapt to these changes in near real time without driving uncontrollable delays or costs. The solution must also leverage any investment in existing infrastructure, regardless of vendor or platform.
Identity and integration-related standards are evolving rapidly in various standards bodies. A solution must take advantage of existing work as well as be able to adapt to new standards as they become ubiquitous. This ensures maximum flexibility when interoperating with other systems and the use of proven, industry-accepted approaches to specific problem sets.
A solution adds little value if it requires the development of new code or a significant integration effort to become operational. To ensure consistency, reliability, and rapid deployment without unnecessary dependencies on third-party systems, all required attributes and technologies should be present in a tightly integrated, turnkey solution.
To allow local administrators to manage the policies relevant to their respective security domains, the solution must permit independent control over authentication and authorization processes. Authentication should occur close to the requestor to ensure maximal reliability in the identity assertion, and authorization of the requestor should occur close to the provider to maintain strict localized access control.
Identity information often provides access to sensitive data and must be protected during an exchange. Security tokens should be shielded from expropriation and not reused through placement in a new message or replay in the same message. To provide a thorough, two-sided audit trail, the requestor's authentication provider and the authorizing provider should securely log all actions performed by a requestor.
Accordingly, there still remains a need for a system that enables integration across identity silos.



BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment or embodiments will now be described by way of example only with reference to the following drawings in which:
FIG. 1 is schematic diagram of the layers in a service oriented architecture;
FIG. 2 is a schematic illustration of the roles in a SOA;
FIG. 3 is schematic diagram of the architectural components in a system of the present invention;
FIG. 4 is a schematic illustrating augmenting an WSDL;
FIG. 5 is a schematic diagram showing the operation of the SOAP agent;
FIG. 6 is a schematic diagram showing a SOAP agent having multiple trust relationships;
FIG. 7 shows a screen layout of a policy manager interface;
FIG. 8 is a schematic showing a list of objects in a policy manager;
FIG. 9 is a schematic diagram showing the architecture of a SOAP agent and Gateway server according to the present invention;
FIG. 10 shows a federated architecture model;
FIG. 11 is a schematic diagram showing the components of an identity bridging system according to the present invention
FIG. 12 is a schematic diagram showing identity bridging from a bridge to a gateway, according to an embodiment of the present invention
FIG. 13 is a schematic diagram showing identity bridging from a gateway to a consumer domain, according to an embodiment of the present invention;
FIG. 14 shows a static identity mapper screen;
FIG. 15 is a sequence diagram showing a gateway server certificate discovery performed by the bridge;
FIG. 16 is a sequence diagram showing an automatic X.509 certificate provisioning;
FIG. 17 is a sequence diagram showing a bridge participating in an identity bridging with two or more gateways, according to an embodiment of the present invention;
FIG. 18 is a sequence diagram showing a flow of messages during a user request;
FIG. 19 is block diagram showing a showing a flow of messages when the bridge performs an identity bridging using a SAML token; and
FIG. 20 shows a schematic diagram of an identity bridging system according to the invention using a SAML credential source.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following description like numerals refer to like structures and processes in the drawings.
In one general aspect the present invention seeks to provide a system and method for securely establishing a person or application's identity and sharing that identity globally across any domain or enterprise.

    
    
        In accordance with one embodiment of the invention there is provided in a network, a method for providing authorised access, the method comprising the steps of:
        
            a. receiving from a user in said first security domain a request for service in a second security domain;
            b. authenticating the service requestor in the first security domain;
            c. forwarding said authenticated request to said second security domain for authorization; and
            d. providing access to the service upon confirmation of authorisation.
        
        
        A further aspect provides the service requestor includes initiating an authentication request against a local authentication source.
        Another aspect provides for the step of using an established key relationship with said authentication source to initiate said authentication request.
        Another aspect provides for including forwarding a security token issued by said authentication source along with said authenticated request.
        Another aspect provides for including applying a security policy from said second domain to said authenticated request, prior to forwarding to said second domain.
        Another aspect provides for including establishing a trust relationship between an authenticator in the first domain and a authoriser in the second domain.
        In accordance with a still further aspect there is provided in a network environment a system for providing authorised access, comprising:
        
            e. a request listener in a first security domain for receiving a request for service in a second security domain from a user;
            f. an authenticator for authenticating the users credentials against a local authentication source and binding a security token to said request; and
            g. a decorator for decorating said request in accordance with a retrieved security policy from said second domain; and
            h. a gateway for receiving said decorated request and routing said request to said requested service upon verification of said request and said policy.
        
        
        Another aspect provides for said security token being a SAML assertion.
        Another aspect provides for the request listener, the authenticator and decorator to be components of a bridge module.
        In accordance with a still further aspect of the invention there is provided a system for bridging user identities between at least a first and a second security domain, comprising:
        
            a. a bridge associated with said first security domain for intercepting messages for service in said second domain from users in said first domain and for authenticating said user identities against a local authentication source by using an established key relationship and for binding a security token with said message; and
            b. a gateway associated with said second domain for gating inbound access and outbound communication with a service in said second domain and for receiving said authenticated message and verifying the authenticity of said security token by using a certificate of the trusted authentication source and authorising access to said service upon confirmation of said authorisation, such that the authorisation is independent of the identity of said user.
        
        
    
    


In another general aspect the present invention seeks to provide a system for enforcing policies on access to Web services on one or more server computers by one or more client computers, the computers connected to one or more networks through one or more network interfaces.
The following description is provided as background to this aspect the invention.
The present invention operates in a Service Oriented Architecture (SOA) wherein a Web services provider domain is secured by a gateway and the gateway coordinates and enforces policies that apply to these services, and coordinates and negotiates security policies with requesters (clients). A description of the components in this operating environment is presented as follows.
Service Oriented Architecture (SOA)
To support these Web services in the Internet, a new architecture was defined, termed SOA, the Service Oriented Architecture. This new architecture describes how users may find Web services, how a potential user can access such Web services, and a language describing the interfaces to these services.
The communication protocol for these Web services is also defined by a new protocol, called Simple Object Access Protocol (SOAP).
SOAP is a way for a program running in one kind of operating system to communicate with a program in the same or another kind of an operating system by using preferably the World Wide Web's Hypertext Transfer Protocol (HTTP) and its eXtensible Markup Language (XML) as the mechanisms for information exchange. Since Web protocols are installed and available for use by all major operating system platforms, HTTP and XML provide an already available solution to the problem of how programs running under different operating systems in a network can communicate with each other.
SOAP specifies exactly how to encode an HTTP header and an XML file so that a program in one computer can call a program in another computer and pass it information. It also specifies how the called program can return a response.
One of the main principles of an SOA is the concept of loose coupling. In a loosely coupled system, connections and interactions between various components are flexible enough so that changes in the interface of one component will not lead to a breakdown of another component. In order to enable loose coupling, three main Web services standards have evolved, all based on the fundamental XML standard. Each of these three standards are illustrated as a stack of layers in FIG. 1 and are:
WSDL (Web Services Description Language). An XML based Interface Definition Language (IDL) similar to other IDLs defined for example in the CORBA architecture. A WSDL document described the functional aspects of a service, such as the format of the input and output messages, and the URL to which the SOAP request should be sent to invoke the service.
UDDI (Universal Description, Discovery and Integration). An XML and SOAP based API specifications for service description publication and discovery. A UDDI server acts as a registry for Web services, and provides a mechanism to locate services and retrieve their interfaces.
While the platform and tools vendors have made available a variety of technologies to handle the layers in the Web services stack (such as SOAP and WSDL toolkits and UDDI implementations), the bulk of the effort has been directed to the provisioning, of the various Web services, with the creation of deployment environments and management tools.
Unfortunately, deployment of Web services is hampered by the problem of providing secured access to these services, and describing policies governing how Web services and their client applications interact.
For example, current security implementations and mechanisms introduce brittleness and tight coupling between the client applications and the Web service, leading to solutions that are not easily reusable, or that require expensive re-development when security policies or agreements change. Furthermore, current platform vendors have not considered how both sides of Web services transactions (provider and consumer) should be coordinated.
Current technologies address security issues, by providing two kinds of solutions, both geared mainly to Web service providers. These include tools for developers, making security a software development problem and static firewall solutions that perpetuate the brittleness of tight coupling between systems. Very little has been done to address the more practical, real-world, aspects of securing, coordinating and customizing Web services in a dynamically at run-time, especially in an environment where typically a Web service will have multiple consumers with varying security requirements and policies.
Technologies integrating all layers of the Web services stack (including SOAP, WSDL and UDDI) for both service provider and consumer are missing. This lack of solutions makes it difficult for many organizations to justify a full and public adoption of Web services technology, regardless of its eventual promise.
Tight Binding of Services to Requester
In FIG. 2, there is shown schematically, the roles and sequence of events in an SOA. A Service Provider publishes a description of its service to a Services Broker, typically a UDDI server or node which operates as a repository. This service description also typically includes a WSDL document. Before the client can request the service it need to find the provider. Upon request, the service broker (UDDI node) returns a document that allows the client to locate the particular providers interface then bind to the provider. It then invokes the service through the bindings described in the interface. All interactions between the three entities are typically SOAP requests.
One of the limitations of this architecture occurs when issues of security and policy are involved. In typical real world scenarios, services that are provided between business entities, whether within the departments of a particular organization, or between business partners, are not anonymous. Instead, they are governed with sometimes-strict security policies and maybe even different usage and Quality of Service (QoS) policies and agreements.
Despite recent advances in tools and infrastructure, the state-of-the-art in Web services security remains laborious and prone to error. Security best practices are ill defined. What little implementation exists is littered throughout the Web services stack, appearing in the transport layer, at the application server, and in every individual Web service protocol and implementation. This creates a number of vulnerabilities and multiple points of failure that conspire to complicate the developer's and the administrator's jobs. Once an administrator deploys a service, security becomes instantly entrenched and difficult to manage. Any change an organization makes to its security policy, any alteration made to signatures, encryption, or even server location, seems to necessitate a costly new development effort, both on the server side and on the client side. These issues combine to make solutions that are simply not reusable.
Implementing security policies into the code of the Web service is undesirable for many reasons. Web service and XML security is a complex matter and very error prone, especially for non-expert developers, and will add a large amount of time and expense to any Web services deployment project; policies can and will change over time, leading to more time and expense and possibility of error any time the code base has to be modified; and finally, as partners are added or removed, or their individual policies are modified, the Web service code, with the security code embedded in it, will become extremely difficult, if not impossible, to manage.
But even if all those obstacle were surmountable, a major issue remains: by implementing complex, but necessary, policies on the Web service side, the burden of implementing security is placed on the client application. This is a very serious responsibility, and in many cases consumers of the Web service are not up to the challenge of implementing the required security. More importantly, however, any change in policies on service side will need to be mirrored on the client side, in order for the system to remain operational.
There remains a need for a solution that both manages and coordinates security, end-to-end across a Web services integration lifecycle and which is a centrally administrable, standards-based solution that restores fine-grained security control and visibility to IT managers at the Web services application layer.
A general aspect of the present invention comprises a system for enforcing policies on access to Web services on one or more server computers by one or more client computers, the computers connected to one or more networks through one or more network interfaces, each computer having one or more memories and one or more central processing units (CPUs), the system comprising: one or more logical expressions that define constraints on one or more service releases; a gateway process receiving service request messages from one or more of said clients for i) identifying said service request message, ii) processing said identified service request message in accordance with one or more of said logical expressions associated with the requested service and iii) providing access to said requested service if the constraints are satisfied.
A further aspect of the invention includes an agent process associated with one or more said clients, for receiving service request messages from an associated client, said message destined for a requested service and applying to said received request message one or more of a subset of said logical expressions associated with the requested service for forwarding to said gateway process.
A further aspect of the invention provides for a method for enforcing policies.
In a specific aspect an embodiment of the invention consists of four architectural components:
i) a Gateway server, which is a network appliance that processes SOAP messages destined for protected Web services. The Gateway coordinates and enforces policies that apply to these services, and coordinates and negotiates security policies with requesters (client).
ii) a Policy Manager, which allows administrators to: establish trust and identity sources that integrate with existing infrastructure; use these sources to define security policies through a declarative policy language of assertions; and modify existing policies and propagate them to existing clients. Through the policy Manager, Web services security becomes an easy, repeatable and reusable administrative task instead of a complex custom development problem.
iii) a SOAP Agent, which establishes a PKI (public key infrastructure) based trust relationship with one or more Gateway Servers, and resides on each Web service requester. The Agent automates the negotiation of security policies between the Gateway and its clients. Client systems send their unadorned SOAP requests to the local Agent, which then takes care of applying the necessary headers and transformations required by the applicable policies. Changes to security policies administered at the Gateway are propagated to the appropriate Agents, which then apply the changes to the messages destined for the Web service in question. Although optional (clients can custom develop applications that conform to the Gateway security policies), the Agent is an integral part of providing true loose coupling between Web services and their clients.
iv) a Policy Assertion Language, (PAL) which ties the three other components together, and provides a language to express the policies created by the Manager, implemented by the Agent, and enforced by the Gateway.
Another aspect of the present invention is to dynamically overlay security on top of existing Web services transactions. In the present model, security is declarative, instead of programmatic; it shifts the responsibility for implementation of security from each individual software developer, and places it in the hands of a security administrator. Declarative Security allows for late, runtime binding to an organization's security policy. This allows an administrator to change policy at any time, and have the update instantly applied to all transactions governed under the policy, all without modifying a single line of code.
The present invention provides a coordinated declarative security model that can be applied not only to the service provider side but also the consumer side of a web services transaction.
Referring to FIG. 3 there is shown the components for a system 500 for securing Web services 501 according to a general embodiment of the present invention. The system 500 includes a client domain 502 and a Web service domain 504 coupled via the Internet. Communications between the domains are via SOAP messages. Single domains are shown for illustrative purposes only. The client domain includes the client computer 503. The system 500 comprises three major components: a gateway server 506 that resides behind a conventional firewall 508 in the Web service domain 504; a management application software 508 for developing security policies and managing all Web services (the Policy Manager); an agent 510 located in the client domain 502 behind a firewall 512 that secures a transaction according to the policy in effect, before a SOAP message is released to an insecure network (the SOAP Agent); and a programming language that allows administrators to construct complex usage policies and attach them to the protected services (the Policy Assertion Language). In addition the system includes PKI (public key infrastructure) certificate management components 518 and 5520 associated with the client and Web services domain respectively.
The Gateway Server 506 consists of a high performance server executing core messaging, security and management software. Typically residing inside a DMZ, which contains devices accessible to Internet traffic, the Gateway supports an active standby configuration with database synchronization capability.
Collections of Web services 501 can be centrally managed and audited through the management application 508 linked to the Gateway 506. The Gateway 506 may also communicate with an existing directory service 522. The Policy Manager allows administrators to decouple policy control from a service's programmed business logic so that no manual configuration or integration of the Web services themselves is required.
Each of the component functions will now be discussed in detail below.
The Gateway Server
The Gateway Server 506 acts as a gatekeeper mediating all Web services activity entering an organization. It is a software engine to create, publish, and enforce policy for all Web services. It shields access to internal services, ensuring that only those messages that pass all of its security tests are ultimately forwarded to the protected service. The Gateway 506 provides administrators with a single point of management, regardless of whether an organization has a single, standalone Gateway or a cluster of parallel systems for high availability. It centralizes the security management of all Web services using a single, intuitive and consistent user interface, thus eliminating any chance of a configuration error that could compromise the security integrity of the entire network.
The Gateway 506 is fundamentally a message-processing engine. Every Web service published through the Gateway is subject to policy; the Gateway identifies and processes every SOAP message under the policy registered against that service. Internally, services and operations are categorized according to their WSDL representation, which fully describes a Web services API (application programming interface) as it is bound to a transport. The WSDL representation defines how the system can identify a message, through URN namespace, HTTP (hypertext transportation protocol), a SOAPAction header, or binding to a specific URL (uniform resource locator).
Clustering for Performance and Availability
The Gateway includes a number of different, flexible deployment options. Each gateway can operate independently, in stand-alone mode. Organizations requiring high availability and scalability can deploy Gateways in redundant clusters. Clusters members are all synchronized to provide identical views of the policy store, the internal identity provider, and any other common system configuration data.
Simplified PKI Deployment
The downfall of many PKI systems in large organizations has been the complexity and expense associated with setting up a centralized system that interfaces with a diverse number of different applications and clients. This is further complicated by gaps in the standards that limit interoperability between applications. In contrast, the Gateway Server 506 of the present invention operates as its own CA (certificate authority). The integrated CA, provides simplified distribution of certificates to clients, instant and automatic checks of certificate status and revocation, and intuitive management of the system. In a Gateway cluster, a single appliance is delegated to being the root CA; this root appliance is responsible for processing all client signing requests, and creation of all SSL (secure socket layer) certificates in the cluster. In one embodiment the root CA's private key store is password protected and encrypted using a triple DES cipher. For added physical security, it may be persisted to a removable USB dongle that administrators can be safely separate from the appliance during regular operation. Other encryption techniques could equally well be used.
Simplified Management of SSL
The Gateway 506 of the present invention greatly simplifies the management of SSL in Web services transactions. SSL is an assertion in a policy that an administrator can choose to activate at any time. Each Web service 501 can use SSL between the client and the Gateway Server, and/or between the Gateway and the downstream service itself. Having the ability to disable SSL on the last mile is especially important to many organizations. This eliminates the need to have server-side certificates on every internal system (which is expensive and a significant administrative burden), yet it still protects the segment of the connection that traversed the public Internet. It also eliminates the need to reconfigure existing Web services to support SSL, which often requires clumsy code modification, changes to server configuration, and local, client-side management of certificates in a trust store. Finally, SSL is computationally expensive. A common rule of thumb when sizing Web servers is that SSL increases processing burden by 30%. In a large installation, this can become a significant expense.
Centralizing SSL processing to the Gateway Server 506 greatly eases administration and cost, since only a single certificate is required (included with every Gateway Server). The Gateway Server 506 architecture allows it to accept a number of third-party SSL acceleration boards. Experience on high volume web sites has proven this a cost-effective solution to increase transaction throughput and promote overall system scalability.
The Gateway Server 506 can also make use of SSL metadata when configuring security policy. HTTP basic authentication headers can be a source of credentials for any authentication assertion. Administrators can enable client-side certificate authentication—an optional feature of SSL that is well suited for sites requiring strong client authentication. A standard certificate authentication filter accepts and validates all client-certificates exchanged over SSL.
This fine-grained control provided by the present assertion framework is especially important for installations that support multiple security models. For example, an organization may simultaneously support legacy SSL transactions with one trading partner, and newer WS-Security based policy with another. Although the two transactions mine credentials from different sources, the Gateway 506 uses the same assertion and pluggable provider to authenticate against the local identity server. This greatly simplifies administration, and lessens the chance of introduction of a security hole through oversight.
Augmenting UDDI and WSDL
UDDI and WSDL are both important parts of Web services; however, both neglect to address security in a useful manner. The present invention addresses this problem. The UDDI uses SOAP as an access method; thus, the same finely grained, flexible security model for regular Web services is applicable to any private UDDI registry. Accordingly, the Gateway Server can act as a secure proxy and provide identity based access policies to any internal UDDI server, thus making good on the promise of service publication to trading partners. Furthermore, through the use of transformation filters, UDDI query responses can be personalized to fit the requester, providing true UDDI proxying. This finally extends all security elements to UDDI, including authentication, authorization, access control, confidentiality, personalization and even non-repudiation.
WSDL provides a means to describe a service in both abstract and concrete terms, but it offers nothing to accommodate security. Referring now to FIG. 4 there is shown schematically a typical Web services application system 600, according to an embodiment of the present invention, illustrating message flow when a client downloads a WSDL description through a Gateway, either in response to a UDDI query, or as a standalone URL. The system 600 shows a trading partner client domain 601 having an administrator computer 602 coupled through the SOAP agent 510 to the Internet. The Web services domain identified as the corporate network includes the gateway server 506, a web server 608 and a UDDI registry 610. When a client downloads a WSDL description through the Gateway, the Gateway can optionally augment the file to describe a secure implementation of the service. The simplest augmentation is simply a rewriting of the internal URL in the soap: address element of a SOAP message inside the service element to point to the Gateway instead of the actual physical service location. This assists in the automatic generation of stubs or proxies for the remote service, ensuring that they route requests through the Gateway and thereby subject to the policy 612 in effect. This is termed Endpoint Address Translation (EAT), and may be considered to be an application-level security analog of NAT (network address translation) and thus even more important to a mature security model.
But WSDL without a concrete security policy describing how to access the service is still not a complete solution. Ideally, the WSDL augmentation should describe the security expectations of the Gateway for access to that service. Such as for example, does this service require authentication? What kinds of credentials are required? Are they rendered into HTTP headers or WS-Security headers?
Thus, the Gateway can bind a security policy 612 to a WSDL description, and publish this aggregate description 618 to its clients. The combination of these two documents fully describes a secure version of the service. This provides a standards-based method for adding policy assertions to WSDL that is compliant with existing client-side code generation tools, and “future proofs” the investment against the time when security-aware, third-party code-generation become available.
Credential Chaining
With the proliferation of corporate Intranet sites, organizations quickly identified the need to unite all their disparate credentials under a single, global ID. Web services share the same challenge, and the present invention provides a solution to this issue. Each Web service can be configured to authenticate against a global ID (using any of the credential sources, such as basic, certificate, digest, etc), which is then chained (or mapped) to credentials appropriate to a local service ID, such as identity-based local database accounts.
The Gateway can also consolidate multiple incoming identities into a single downstream identity, such as a limited access database account. This removes the burden of managing multiple identities, which are likely to change frequently, on the downstream service. For example, whenever the remote credentials change, the change need only be reflected on the outgoing Gateway, not the actual client. This is a simple, centralized administration task, rather than a programming challenge and can realize tremendous savings during deployment of a large number of clients.
The SOAP Agent
Referring to FIG. 5 there is shown a schematic diagram of the client side of a Web services system. The gateway is only half of a security solution. Without this support, client-side programmers would be forced implement their own security against a security policy set by the administrator, a difficult and tedious task which is also prone to error, and expensive to maintain. For example if a VPN server came with no clients, and simply expected that users would build their own IP security implementations. This would clearly be untenable and unsustainable, but it is not unlike what many Web services firewall solutions expect.
The SOAP Agent simplifies the task of layering security onto Web services transactions. The Agent is the key to the late-biding, declarative security model of the present invention. The Agent understands and follows the policy directives of the Gateway; policy changes made by an administrator are instantly loaded and applied on the Agent without changing a line of code in the actual Web services application. The Agent also manages client-side certificates issued by a Gateway, simplifying this complex process tremendously over existing browser and email models and providing the benefits of strong authentication, digital signing, and message-based encryption.
As shown in FIG. 5, the SOAP Agent intercepts a Web services transaction (unsecured message 702) before it is sent across the network to the Gateway. The Agent loads policies (the PAL policy document 708) from the Gateway 506 the first time a service is called. These policies are specific to the clients being serviced by the Agent and are normally a subset of the policies associated with the services protected by the gateway. For every SOAP message the Agent receives, it decorates the message according to the rules defined in the policy. For example, the policy may demand that the message body be encrypted with AES encryption under the WS-Security standard, and that the entire message body signed by the client's private key. The Agent will interpret this policy, and modify the transaction accordingly before sending it downstream to the Gateway.
Policies are cached on the Agent, and are reloaded whenever a transaction fails because a policy was changed on the Gateway. In this manner, all clients instantly adhere to security policy changes. For example, suppose a Web service is deployed during a testing phase without any message or channel encryption to aid in debugging. Once testing is complete, the security administrator can select SSL-based security in the policy for that service. The Agent will then be refused entry once (because it is not compliant with the current policy), prompting it to reload the policy description and continue, this time using SSL for the connection. All this will happen with no code changes on the client—and indeed, a user would not even be aware that a significant change in transport occurred.
Of course, not all policy assertions are appropriate for export to the client. Authorization lists, for example, are relevant only to the Gateway, as these could be exploited by a hacker if they were made public. Thus, the Gateway publishes a filtered “view” of the policy in effect, describing only what morphological changes are required of the message or transport, and nothing about identity expectations, internal routing information, etc.
The SOAP Agent can be run in two different modes: one standalone, command-line driven, appropriate for server installations; and one with a rich Graphical User Interface (GUI) 704 for more interactive users. In both modes, user intervention is minimal or non-existent, depending on security requirements. For example, passwords to unlock a client-side certificate or credentials to assert an identity on the Gateway can be entered when the Agent is started, or they can be added only as needed: the Agent will launch a popup query for credentials the first time they are demanded by a remote server.
Web services clients should not require code modification to use the Agent. Enabling an application to make use of the Agent's services is as simple as changing the URL indicating the target Web service to point to local host instead of a remote server. For the majority of Web services development kits, this is easily accessible in an application property file (it is common for the target URL to change frequently as an application is moved from development to testing to deployment, so this property should be easily accessible). In some instances in which client stubs are automatically generated from a WSDL file describing the service, a minor modification to the location attribute of the soap: address element can be applied. This can be done either automatically by referencing the WSDL through the Gateway WSDL query and augmentation service, or by modifying the WSDL source file and re-applying the stub generator.
A single SOAP Agent can also be bound to multiple Gateways as shown schematically 800 in FIG. 6. These can be within a single organization, but under a single PKI administrative domain. For example, a large organization may have multiple Gateway clusters in different departments, united under a single PKI root certificate. In this case, the Agent is configured to trust the single organizational root certificate and is bound independently to the departmental clusters. A binding can also co-exist within the same Agent to a completely separate organization, this with its own independent root certificate. Transactions will simultaneously be routed to the correct Gateway, and the Agent will ensure that the appropriate certificates and trust relationships are applied to the appropriate transactions.
The Policy Assertion Language
Web services are invoked through SOAP messages. The present system inserts itself into a Web service's SOAP stream, augmenting it, transforming it, and inspecting it. The processing algorithm that the SOAP Agent and Gateway Server apply to a SOAP stream is what is termed Policy. Policies or logical expression may consist of chains of concrete rules, preconditions, and tests that Web services transactions are subject to if they are to pass through the Gateway. The Gateway securely publishes a subset of its policy expectations that are appropriate to each SOAP Agent to allow the Agent to prepare SOAP messages into a form that the appliance will accept (subject, or course, to the tests embodied in the policy).
Every service published to the Gateway Server has a policy attached to it. These policies are implemented as a collection of policy assertions using a Policy Assertion Language (PAL). An assertion represents a statement about the state or content of a message. Usually, every assertion must resolve to either true or false. For example, an authentication assertion might state: this message must provide HTTP basic credentials. A routing assertion might declare: route this message to the downstream URL https://ws2.layer7tech.com/Stocks/quoteService.
An assertion then is the embodiment of a processing algorithm and may contain some additional properties. In the first example, the processing algorithm extracts the HTTP Authorization header from a SOAP message bound into an HTTP POST, as per the SOAP specification; in the second, it is to POST the stream to the downstream URL. The first example has no set properties but clearly has state defined as a side effect—that is, the extracted credentials. In the second example, the downstream URL is a property associated with the assertion. Properties of an assertion are instance variables, not static; as we will see, they can take on different values in different contexts.
Identity is another common assertion. For example, an identity assertion might state that: the message must contain user Alice's credentials. In this case, the processing algorithm is to validate the credentials against an identity server, such as a corporate-wide LDAP server. The property for an identity assertion is the unique identifier for user Alice, and of course a reference to the identity server hosting this identity.
But assertions on their own can lead to numerous ambiguities. For example, how can one validate an identity assertion if an associated authentication assertion, which declares where to locate credentials in a message, is not evaluated first? Similarly, if a routing assertion executed prior to validation of an identity assertion, the policy containing these would not be very effective if its intent is to protect the downstream service from access by unauthorized users. To remedy this, out technology provides a very rich and unambiguous processing model that governs how policy is applied to a SOAP message (the Gateway SOAP Processing Model).
The PAL provides a rich policy expression language where policies are represented as a tree of policy assertions. Internal nodes of the tree are called composite assertions and provide a mechanism to express conjunctions (logical AND) and disjunctions (logical OR). These composite assertions collect sub-assertions as an ordered list of children, where the order defines an explicit processing model. For example, a composite assertion might declare that: all child assertions must evaluate to true (AND). Under this processing model, every child is evaluated, from top to bottom. Execution of sub-assertions is suspended if any assertion evaluates to false, and the resulting composite assertion evaluates to false. Another composite assertion states: at least one assertion must evaluate to true (OR). Under this processing model, every child assertion is evaluated until one resolves to true, at which time further execution of any remaining children is suspended and the composite assertion returns true.
Root Policy Assertion
At the root of the policy is a composite assertion that declares that all immediate children must evaluate to true. The Gateway Server evaluates each child in order, from top to bottom; ordering is important—as observed above, there are circumstances in which an assertion is only relevant if a previous assertion has already been evaluated and any side effects of its operation are available for inspection.
Transport Security Assertion
The first child assertion declares that SSL transport is a requirement for this message. The Gateway validates that this is the case, and proceeds to the next child assertion. Suppose, though, that the sender delivered the message using regular, clear text HTTP without SSL. In this circumstance, the SSL assertion evaluates to false, and the composite assertion at the root must also resolve to false. This results in a rejection of a message by the Gateway, which indicates this to the client in a returned SOAP fault.
Authentication Method Assertion
The next child assertion demands that the message contain HTTP basic authentication credentials. These are in a known location, the HTTP metadata, and are extracted from the message and kept for later processing.
Identity Assertions
The next child is not a leaf node, but another composite assertion—this one declaring that at least one of the child assertions is true. This composite assertion exclusively contains identity assertions—obviously, it is implementing an authorization and authentication test.
Routing Assertions
The final assertion is a routing assertion. When this is executed, the message is sent to the URL set as a property of the assertion. This operation may include credentials for the downstream server—a feature called credential chaining—and may use SSL to ensure confidentiality, integrity, and server authentication for the downstream transaction. If this final assertion evaluates to true, indicating successful transmission of the message downstream, then the root assertion also resolves to true, and any data received from the routing assertion is returned to the calling client.
Identity Based Policy Modeling
Modeling policy as an ordered tree of assertions can be tremendously powerful and flexible. Deep, nested structures can be constructed to define a logical message-processing model that accommodates extremely complex service definitions and implements multi-step security processing requirements. For example, identity-based polices, in which a different processing model is applied depending on the proven identity of the requester, are as simple to model as a sub tree of the relevant assertions, subordinate to each identity assertion.
In this light, policy becomes much more than a means for defining simple security definitions: it can make declarations about reliability, transaction boundaries, routing through intermediates, message transformation, etc. It also forms the basis of negotiation between trading partners, where security expectations provide options that need to be resolved into a security contract—much like the SSL cipher negotiation—under which trading can be safely conducted.
By participating in both sides of the transaction, using policy to coordinate each side, The Gateway Server allows Web services applications to be completely insulated from the uncertainty of emerging standards, while providing the beginning of true loose coupling between services.
PAL Policy Assertions
PAL assertions are implemented using a Java interface definition, and it is therefore very easy to extend the basic set.













CREDENTIALS
HTTP basic authentication



HTTP digest authentication



HTTP client-side certificate authentication



WS-Security basic authentication



WS-Security digest authentication



WS-Security client-side certificate



authentication


IDENTITIY
Identity in internal provider



Identity in external LDAP provider



Transport protocol



Routing information


SECURITY
SSL transport enabled



WS-Security signature validation



WS-Security encryption/decryption


COMPOSITE
All assertions must resolve to true (logical


ASSERTIONS
AND)



At least one assertion must resolve to true



(logical OR)









The Policy Manager
Referring to FIG. 7 there is shown a screen layout of the Policy Manager GUI 900, which provides a single unified view into the Gateway Server 506. Its primary purpose is as a security policy editor, providing a means to rapidly set up and manage a tree of security assertions associated with a Web service. In addition to policy editing, the Manager is the primary interface to manage users, configure the Gateway, and monitor its continuous operation.
A security administrator can direct the Policy Manager 900 to manage any Gateway Server in a cluster; any changes made to the Gateway configuration through the Manager will be instantly propagated among all other peers in the cluster. Administrators simply need to know the URL of the Gateway they wish to manage. The Gateway is pre-configured with a single administrative identity with membership in an administrators group; additional administrative identities can be added as needed, using the Manager. All communications between the Manager and the Gateway are fully encrypted, and takes place over port 443. The Gateway publishes Web services interfaces for all major administrative operations, which provides a path to fully integrate Gateway management and policy creation into third-party network management tools.
Initial View
The Policy Manager GUI 900 is a rich policy environment, supporting multiple windowpanes, drag-and-drop operation, and multiple wizards to assist in rapidly configuring Web services security. It can be installed on either a Windows or Unix system using a single-click installation wizard. The Manager has an identical look-and-feel on both operating systems, simplifying system migrations and providing maximum deployment flexibility for operations staff.
The upper left frame 902 of the GUI contains the palette of objects that exist on the system. New objects can be added, modified, dragged into policies, etc. The lower left frame 904 lists all the services under management in the system. The right pane 906 is reserved for policy editing. At startup, this frame also contains several convenience links that launch service and user-oriented configuration wizards.
Building a Policy Using a Service Wizard
Administration overhead can be an impediment to business; it can also be the cause of security holes. Suppose a company is in an aggressive expansion mode, rapidly adding new trading interfaces to its core systems. Their need for rapid deployment of these new services to trading partners—driven by market fundamentals—is often at odds with the administrative requirements of tight security. In these conflicts, security too often loses.
The management console 508 includes rapid but secure deployment of Web services, using wizard interfaces and dynamic discovery technology. Rather than forcing an administrator to configure every new Web service manually, the Policy Manager allows administrators to discover new Web services published in WSIL files, or in WSDL descriptions published at any URL, whether on the Web, or on a file system. Discovery mechanisms for UDDI, as well as plug-ins for major commercial and open-source application servers are used. These will support the export of service descriptions for every deployed service—a great advantage for organizations without UDDI.
The wizard interface allows for immediate security provisioning of newly discovered Web services using generic policy templates. Administrators can fine-tune the security policy of a service at any time, such as changing a routing parameter, or adding a new user to an authorization list.
A simple example is using the wizard to securely provision a new service—in this case, a simple “Hello, World!” application—that resides on the internal network. This is a basic service, with no built-in security. Suppose that the administrator wants to make it available to outside trading partners, but corporate security guidelines dictate that all external systems must authenticate on the corporate LDAP directory before being granted access to an internal application.
As a first step, the administrator enters the URL for the WSDL describing the service. The Gateway Server uses WSDL as its internal representation of a service. The WSDL document is used to determine how to uniquely identify the service from its message (e.g. is the HTTP SOAPAction header used, URN namespace, incoming URL, etc), as well as describing the internal URL where the service resides. In the service pane of the Manager, where all the services under Gateway administration are listed, the entire WSDL description is available for review.
Note that if a WSDL description does not exist, an alternate wizard step exists to allow an administrator to describe a service based on only minimal information.
Next, the administrator can override the URL where the service resides. This is especially useful if multiple versions of the service exist, such as in test and production environments. The administrator can also add credentials for the downstream service. This feature, called credential chaining, allows mapping or consolidation of incoming credentials to an identity that is relevant to the downstream server.
Finally, the administrator describes the incoming security expectations for the service. An administrator can configure whether a client needs to provide security credentials, and where these credentials must reside (using HTTP headers, or WS-Security conventions). In either case, authentication can take place using basic user name and password, digest authentication, or certificate authentication. SSL security can be set on or off from this wizard pane. Additionally, the administrator can construct an authorization list using identities from the internal provider, or from an external source such as a remote LDAP server.
The Policy Editor
Fine-tuning of a policy, regardless of whether it was defined manually, or through a wizard, is accomplished through the policy editor frame. The policy editor presents the entire assertion tree, and provides several interfaces to effect morphological changes to the tree. Composite assertions can be added and deleted or moved anywhere in the tree. Leaf nodes can be configured, moved, or deleted, either through a popup menu or as a drag-and-drop from the palette.
The Palette
Referring to FIG. 8 there is shown a screen display 1000 of a palette that provides an efficient way to navigate to important objects in the Manager 508. The palette supports drag-and-drop of most objects into appropriate locations in a policy in the policy editor frame.
Users and groups in the internal identity provider are managed in the palette. Administrators maintain external identity providers, such as connections to corporate LDAP directories, in the palette. Properties appropriate to identity provider instances, such as LDAP URL, search base, etc, can easily be configured from the palette entry. When an administrator creates a policy template, it is made available here. Policy templates provide a means to quickly configure a customized policy that builds on the basic policies created in the service wizard. Finally, all assertions are available in the palette to support rapid construction of policies in the editor frame.
Identity View of Policy
An Identity view of policies may be understood as follows. Consider the following situation: suppose that two different versions of the stock quote service exist, one that provides instant quotes, and one that provides quotes subject to a 20-minute delay. The interfaces for each of these services are identical; thus, the SOAP messages sent to a Gateway cannot be associated with one service or the other simply by their form. Instead, a differentiation may be made depending on identity. Preferred users—perhaps executives in the organization—are to be routed to the instant quote service; all other users are routed to the delayed quote interface.
This is easy to provision on the Gateway using identity-centric policies. In this case, make the routing assertion subordinate to the identity assertion. This could be done in the regular policy editor view; however to assist in building such policies, the Manager includes a specialized Identity View, in which the policy tree is rooted at a static Identity node. The immediate children of this node are the different identities authorized to under this policy to use the service. Each of these identities can have a different assertion sub tree, including any security assertions (such as SSL must be on), message transformational assertions, and of course, routing assertions.
The Solution Architecture
Modular, Connector-Based Architecture
Referring now to FIG. 9, there is shown an architecture for the SOAP agent 510 and Gateway server 506 according to an embodiment of the present invention. The SOAP agent comprises a console subsystem 552, a message processing subsystem 554, a logging subsystem 556, a local PKI 558 and a cryptographic services subsystem 560. The gateway server includes a management services subsystem 582, a message processing subsystem 584, a local identity provider 586, a logging and audit subsystem 588, a persistence manager 590, crypto services 592, a WSDL processor 594 and a replication engine 596. In addition the gateway communicates with external identity providers 598.
The architecture is modular and extendable, in a true service oriented architecture. It makes extensive use of pluggable service modules to accommodate continuously shifting specifications. The message handling subsystems, for example, supports pluggable handler modules. When a message specification changes, or an entirely new message structure appears, a new handler can trivially be integrated into the system.
Pluggable provider modules provide a means to interface with external systems. This solution is designed to integrate with existing infrastructure in the corporate network, such as identity servers, authorization systems, logging sinks, network and systems management applications, etc. Integrating common identity systems such as LDAP (Lightweight Directory Access Protocol) or Microsoft's Active Directory is a trivial exercise using the pluggable interface design. In addition, a well-defined interface exists for the identity provider system, allowing simple extension for unusual or custom identity servers. Similar modules exist for authorization services, allowing integration with existing LDAP or Active Directory groups. Other connectors such as one that implements the emerging SAML (Security Assertion Markup Language) specification, allowing integration with third-party authorization products that operate as SAML assertion servers has been developed. Similarly, an XKMS (XML Key Management Specification) connector has been developed to integrate with existing corporate PKI systems.
Scalability and High Availability
Functionality in this kind of solution has little value if it cannot handle high and variable transaction rates. Despite its modularity and flexibility, the Gateway defines an efficient message-processing path. Parsing and serialization technologies have been improved, using a variety of techniques such as pull parsing and pattern recognition, to ensure that this traditional processing bottleneck is not a cause of undue latency on the system. All assertions are compiled to ensure the fastest possible performance. Policies are cached on the Gateway to minimize retrieval times once a message is identified and is ready for processing. Strategic use of state information further speeds processing, and extensive use is made of asynchronous IO (both at the network and file levels) to ensure that operations such as logging, socket writes, etc are removed from the latency calculation. All transport connectors make use of scalable socket programming; this allows adjust to the system for the most efficient balance between sessions and threads.
The hardware appliance allows tuning of the system for maximum performance. The appliance Operating System (OS) is hardened for security, but also tuned to maximize performance for the Gateway Server application, something that would be impossible for a software-only solution on a general purpose OS. As transaction volumes grow, Gateway Servers can be clustered, using our stateful clustering technology. Clusters support inexpensive, third party load balancers to distribute transaction volume across the Gateway Servers. For example, a conventional HTTP level sprayer can easily accommodate HTTP-bound SOAP messaging.
Clustering appliances also provides high availability. Gateway Server clusters share configuration information (user profiles, policies, etc) between appliance pairs in a peer-to-peer relationship. Any changes made by an administrator to systems in a cluster are immediately replicated among all peers. Any changes made to policy are further instantly loaded into cache to ensure minimal possible latency for policy change propagation in a cluster—essential when responding to an evolving security threat. If a system is offline for any reason during a change, it will re-synchronize as part of its restart operation, ensuring that stale policies or configuration data are not used in any subsequent transactions.
Audit, Logging, and Monitoring
The Gateway Server features richly configurable logging and alerting framework. Both logs and alerts can route to a variety of different sinks. A connector is available for simple file system logging, with rotation features. Logs can sink to UDP and TCP sockets. Log entries are in simple text format; these can be easily rendered to different target formats. These logs can also be viewed anytime through the Policy Manager, with simple filtering based on severity.
The SOAP Agent similarly features extensive logging of events; these can be viewed selectively from the Agent GUI, or in a user-accessible text file. Client logs can include a trace of all transaction content for debugging purposes.
A fully configurable, event-based alerting system will also be available in the next major release. This will allow administrators to set traps for important system events, such as low memory, low disk space, unusually high access rates or large numbers of access failures. These alarms can be propagated to email, pagers, or third-party network management package.
In summary, Web services technologies offer a very compelling vision of loosely coupled systems, where services are published, discovered and invoked just in time. Unfortunately, real world deployment of Web services is hampered by issues such as the need to secure access to these services, and the problems of describing policies around these implementations and coordinating them with the various clients. All current security implementations and mechanisms introduce brittleness and tight coupling between client and service, leading to solutions that are not reusable, and that require expensive re-development any time security policies or agreements change. The current platform vendors do not address the problem since the bulk of their efforts have been directed at the provisioning side of the equation, with no consideration of how both sides of Web services transactions (provider and consumer) are to coordinate.
The solution presented here is the first solution to tackle the problem of both managing and coordinating security, end-to-end across a Web services integration lifecycle. It consists of three major components: a server that resides behind the conventional firewall (the Gateway Server); a administrative application to develop security policies and manage all Web services (the Policy Manager); an optional client-side agent that secures a transaction according to the policy in effect, before the SOAP message is released to an insecure network (the SOAP Agent); and a rich policy expression language (the Policy Assertion Language).
This is a high performance; high availability solution that allows administrators to decouple control of security and integration policy from a service's programmed business logic. Collections of services can be centrally managed and audited, virtually eliminating manual configuration or integration of the Web services. Client-side interactions can be completely automated, dynamically reflecting changes in security while removing the complexity associated with the management of keys, certificates and policies.
Identity Bridging
The second aspect of the present invention as mentioned earlier provides a turnkey, reusable, and standards-based system and method for overcoming the challenges of disconnected identities. The system secures XML and Web services-based application integrations across federated security domains using three components: a gateway for XML security, a manager for fine-grained security policy configuration, and an agent or client proxy for the coordination of security preferences across multiple security boundaries. Each component solves a portion of the challenge; together they combine to provide an ideal solution to the identity bridging issues.
Referring now to FIG. 11 the components of an identity bridging system according to an embodiment of the present invention is shown generally by numeral 1100. The system includes a service consumer domain 1101 and a service provider domain 1102 coupled via a network 1103 (such as the Internet or an Extranet). The service consumer domain 1101 includes one or more users 1111 (the term “user” can represent an individual human or machine) coupled to one or more client applications hosted on one or more computers 1112 in the domain 1101 and an identity server 1114 for storing user identities (The term “identity” or “identities” includes the identity of both users and groups of users), as is known in the art. The a service consumer domain 1101 also includes a bridge application 1110 deployed as a standalone module or integrated with the application server 1112 in the domain 1101 for intercepting messages from a requestor (user) in the domain 1101 destined for the service provider domain 1102. The service provider domain 1102 includes a Web services server 1116, a gateway computer 1104 provisioned at the perimeter of the service provider's security domain for providing centralised control of access to the Web services and for enforcing security policy applicable to the domain 1102 (i.e. gating of inbound access and regulating outbound communication). The gateway 1104 also performs various XML and Web services security enforcement activities, including threat protection, access management, privacy enforcement, data validation, routing, transformation, and auditing, as will be discussed later.
The system may also include a policy manager 1120, which is, a comprehensive administrative application used to configure security enforcement policies for protected Web services 1116. Identity-based entitlements and security policies are created and enabled through the manager 1120. External credential, PKI (public key infrastructure), and SSO sources can also be configured through the manager. A detailed description of the policy manager 1120 will follow later.
The bridge application 1110 automatically establishes a PKI-based trust relationship with one or more gateways 1104, applying security policies defined in the manager 1120 to facilitate integration between client applications 1112 residing in one security domain 1101 and Web services 1116 residing in another security domain 1102.
The system can be configured to solve a number of different Web services identity federation problems. In a simple scenario where there is a provider of application functionality (exposed as a Web service) in one security domain and a requestor of that functionality in another security domain, the system can be deployed as illustrated in FIG. 11.
As described above the gateway 1104 is provisioned at the perimeter of the provider's security domain 1102 and provides a central point for controlling access to Web services 1116 and enforcing security policy for that domain. Using the manager 1120, a security policy is configured for accessing each Web service 1116 in the domain 1102. The policy defines requirements including transport protocol, threat safeguards, access permissions, signing and encryption expectations, and other preferences. The policy could also specify a transformation for the incoming identity credentials in identity re-mapping.
As also mentioned above, the bridge application is deployed on the same host as the requestor's application or client to intercept messages destined for the Web services provider 1116. When configured to access one or more identity sources 1114—such as an LDAP or MS-AD directory, a Single Sign-On (SSO) system, or a SAML issuing authority—the bridge authenticates a users credentials for an outgoing request against the appropriate source 1114. This configuration ensures that authentication takes place as close as possible to the identity store and is under the control of the appropriate local domain administrator (not shown).
Referring to FIG. 12 there is shown a system for identity bridging from a bridge 1110 to a gateway 1104 according to another embodiment of the invention. The identity bridge authenticates credentials against a local identity server and retrieves a SAML assertion from a SAML identity server 1214. The SAML assertion is bound to the message by the bridge 1110, signed and forwarded to the gateway 1104. The bridge 1110 for non-repudiation logs all actions and messages.
In other words, when a message bound for the gateway 1104 protecting a Web service 1116 is intercepted by the bridge 1110, the bridge 1110 uses a pre-established key relationship to initiate an authentication request on behalf of the client application against the local authentication source, in this case the corporate internal PKI 1215. The resultant artefact 1250 of the authentication (i.e. cookie or SAML assertion) and the originating identity 1252 are bound into the message 1258 by the bridge 1110 and signed, sequenced, and forwarded to the provider's gateway 1104 for processing. The message may be encrypted or subject to other requirements as defined in the security policy for the protected Web service.
Tight, signed binding of the credentials and authentication evidence, combined with automatic sequencing, ensures that no intermediate or replay attacks are possible even if the message is intercepted during transmission. This binding also provides powerful transactional evidence for local auditing and non-repudiation.
Gateway Authorization
Referring now to FIG. 13 there is shown a system for identity bridging from a bridge 1110 to a gateway 1104 in a consumer domain according to another embodiment of the invention. In this embodiment, an administrator establishes a trust relationship with a consumer by importing the certificate of its SAML issuing authority as a trusted authentication source. The administrator can optionally import remote identity common names (using LDIF or CSV format) to gate policies based on remotely authenticated identities.
Administrators can choose the authorization model used by the gateway on a service-by-service basis. When a message is received by the gateway 1104, subsequent processing depends on the defined Web service security policy for the requestor's identity. The gateway first checks the integrity of the bundled identity 1258, the authentication token, and the message itself. The authentication token is examined by the gateway 1104 to ensure that it has not timed out, an important consideration when using potentially long-lived cookies or SAML assertions. The certificate of the trusted authentication source is used to verify the authenticity and source of the authentication token that is presented. Additional policy processing can also be performed by the gateway based on specific message elements or various assertion-based requirements that are independent of identity or the authentication token.
If the application already has a hard-coded authorization process or if the incoming identity has no context within the provider-side Web services' security domain, then the originating identity and token can be stripped out before forwarding the message to the provider's application for additional authorization. Again, the local audit trail that exists for all transactions and administrative functions provides positive evidence for non-repudiation or regulatory compliance issues.
Identity Re-Mapping
FIG. 14 shows a screen capture of a Static Identity Mapper GUI 1400, according to the present invention. An ability to make fine-grained decisions based on the actual originating identity of a Web service message may be critical in some applications. For example, a single security policy may have different processing steps for different identities or roles, or an identity may have to be re-mapped from the requestor's context to another identity that is meaningful within the provider's context. In both cases, access to the original identity provider could be used but may not be possible due to the presence of firewalls or regulatory issues.
To perform policy processing based on originating identity, a subset of identities in various formats can be imported out of band from the requestor-side into the provider's gateway. These identities reside in the gateway's secure internal identity store and can only be accessed by authorized administrators through the manager 1120.
Web service securities policies can be built that make fine-grained authorization decisions—such as message processing, transformation, or routing—based on these imported identities. Messages can then be forwarded to the appropriate application with either no identity or with a local identity that has been derived, or re-mapped, from the original incoming identity. This might include mapping individual requestor identities to local SSO provider identities or mapping requestor role-based identities to provider-based roles. The mapping is defined within the policy and can be changed at any time without inadvertently violating any hard-coded authorization logic in the application or breaking the integration itself.
Server Certificate Discovery
Referring to FIG. 15 there is shown a sequence of steps between the bridge and the gateway during server certificate discovery. Server certificate discovery is performed by the bridge the first time it needs a gateway's server certificate. Typically, this will be the very first time the bridge needs to open an SSL connection to the gateway. Server certificate discovery might be triggered by any of the following:

    
    
        Attempted SSL connection to consume a service
        Attempted SSL connection for policy discovery
        Attempted SSL connection to a Gateway security token service
        Attempted SSL connection to a Gateway certificate authority service
        Any other attempted SSL connection to a Gateway
        A request whose effective policy calls for request encryption
        A request whose effective policy promises response signing
        Other triggers are possible
    
    


The steps shown in FIG. 15 are as follows:

    
    
        1. The Bridge prompts the user for their username and password, if not already known. Then the Bridge makes an unencrypted HTTP GET request to the certificate discovery service on the Gateway. The Bridge includes its username and a nonce as a query string, but does not reveal its password at this time.
        2. The Gateway generates zero or more Certificate Check Hashes. For each user account that the Gateway knows about with a matching username, and for which the Gateway has access to that accounts hashed password (also known as H(A1), and itself consisting of the MD5 of “username:realm:password”), the Gateway computes the checkhash MD5 of (pass, nonce, idp, cert, pass) where: pass is H(A1); nonce is the nonce chosen by the client; idp is the number of the ID provider in which the matching username was found; and cert is the encoded bytes of the server certificate. One HTTP header is included in the response for each check header produced.
        3. The Gateway returns its encoded X.509 certificate as the body of the HTTP response as type application/x-x509-server-cert, and the check hashes inside HTTP headers.
        4. Using its knowledge of the password, and the information returned in the response, the Bridge computes its own value for each Check Hash. If at least one value matches, then the Bridge has a level of assurance that the certificate it holds is the intact SSL certificate of a Gateway that knows the password for this account.
        5. The Bridge saves the server certificate in its local trust store for this Gateway account
    
    


Referring to FIG. 16 there is shown the sequence of steps for automatic X.509 certificate provisioning by the bridge, with the gateway being a CA service. In the event that it needs a client certificate, the bridge can contact an appropriately-configured gateway to do automatic X.509 certificate provisioning. Some of the security features of the Bridge can only operate once the Bridge possesses an X.509 client certificate and private key whose corresponding public key is known to and trusted by the Gateway it is accessing. In some situations, it is desirable to allow the Bridge to provision its own client certificate automatically by applying for it from the Gateway.
The Bridge uses username and password authentication to bootstrap the client cert provisioning. Once a client cert has been successfully obtained and used to consume any service from that Gateway, that username and password can no longer be used to apply for a client certificate in this fashion.
The Bridge will attempt to apply for a client certificate the first time one is needed. This happens when it encounters one of the following situations:

    
    
        A policy download needs to be authenticated using a WS-Security message-level signature
        A policy download from a Federated Gateway needs to be authenticated using SAML holder-of-key authentication
        A request policy calls for SSL with client cert authentication
        A request policy calls for SAML holder-of-key authentication
        A request policy calls for WS-Security message-level integrity, either directly, or indirectly by calling for message replay protection without explicitly specifying a different protection method
        A request policy calls for establishment of a WS-SecureConversation session with a Federated Gateway
    
    


The steps shown in FIG. 16 are as follows:

    
    
        1. During the first consumption of a service whose policy requires a client certificate, and if no client certificate has been manually imported, the Bridge will generate a private and public key pair for itself and use them to create a Certificate Signing Request (CSR).
        2. The Bridge sends the CSR to the target Gateway to request a signed client certificate.
        3. The Gateway attempts to authenticate this request using the username and password.
        4. The Gateway ensures that this account has not already applied for a client cert, received one, and completed at least one service request using it. If this Gateway account has already been issued a working client certificate, the request is rejected. Otherwise, an account may try again a small number of times to apply for a working client certificate.
        5. The Gateway verifies that the information in the CSR matches the information on file for the user. The Gateway creates and signs a client certificate.
        6. The client certificate is returned to the Bridge as the body of the HTTPS POST response. The Bridge saves the client cert and corresponding private key to the key store file for this Gateway account, protected on disk with the password that was used to obtain it
    
    


Referring to FIG. 17 there is shown the sequence of steps when a bridge participates in identity bridging arrangements with two or more gateways. A gateway administrator is referenced by SSGA admin and SSGB admin for corresponding gateways A and B which are in turn referenced by SSG A and SSG B resepectively. The bridge is reference in the FIG. 17 as Agent.
Referring to FIG. 18 there is shown a sequence of steps when a bridge SSA obtains and applies a policy from a gateway SSG in response to a user request to client software in the bridges domain.
Referring to FIG. 19, there is shown the components of a bridge 1110 when performing identity bridging using a SAML token between a clients network and a service providers network. These components of the bridge include an HTTP request listener, an interface (preferably a GUI) for inputting administrator settings, one or more client proxy's, a message processor, a policy manager, request message decorator, a response undecorator and a WS-Trust SAML token strategy.
The steps described below assume that the target server certificate has already been discovered manually and that a client certificate has already been provisioned either manually or automatically from an X.509 certificate provisioning service on the clients network.
Step 1: The Bridge administrator configures a proxy (here called “/prox02”) to access the “Client's Security Token Service” when it encounters a policy that requires a SAML security token (A proxy is created by the bridge for each set of credentials managed by the bridge).
Step 2: A naive client application, which implements no security features, transmits a SOAP request to the Bridge for eventual delivery to the Target Service (possibly via the service provider's Service Gateway).
Step 5: the message processor gets a policy from the proxy's policy manager.
Step 6: Unless the Bridge user has turned off “Use SSL by default”, the policy download is over SSL with server authentication, including hostname verification. No client authentication is required for this step.
Step 7: the Gateway policy service signs the WS-MetadataExchange SOAP response using an order WS-Security SOAP message signature. The signature covers the body, the timestamp, and the L7a:RelatesTo header. This particular example policy might look similar to this in the target Gateway's manager GUI:

    
    
        SAML Authentication Statement
        Sign request element /e:Evelope/e:Body
        Encrypt request element /e:Envelope/e:Body
        At least one assertion must evaluate to true
        User: ClientUsername [Company A FIP]
        Route to http://backend/endpoint
        Sign response element /e:Envelope/e:Body
        Encrypt response element /e:Envelope/e:Body
    
    


Step 10: When configured to talk to a third-party token service, the Bridge will usually be configured to use an SSL connection, over which the WS-Trust request is sent and the response is received. A third party token service will typically require username/password authentication from the Bridge.
When configured to talk to a local Gateway as the token service, the Bridge will use its client certificate to produce a WS-Security SOAP message signature covering the request message's body and timestamp.
As for the WS-Trust response message that carries back the security token, in this case it will be carrying a SAML assertion. Like all SAML assertions, its issuer signs the resulting SAML assertion in the response before being sent back.
Step 11: In this example the SAML token uses the Holder-of-Key subject confirmation method, meaning the client offers the server a security token, trusted by the server, which says “I have authenticated the holder of the private key corresponding to the public key in the client certificate included in this SAML assertion.” The client proves that he possesses this private key by using it to sign the request message. After successfully validating this signature, along with the issuer signature on the SAML assertion itself, the server knows that a user authorized by the trusted token service sent the message.
Step 13: Although not shown explicitly, but assume the example policy from Step 7 above, the servers policy for this request promises that the response will be signed and have its Body encrypted. The Bridge checks the response to ensure that this is the case: the signature is checked, and the encrypted sections are decrypted. Then the undecorated response message is ready to be returned to the original security-naive client.
Identity Bridging for Cross Domain Application Integration
The following describes the identity bridging mechanism for merging identities from disparate security domains. Identity bridging according to the present invention splits up the authentication and authorization tasks that occur between security domains, delegating authentication to a requestor domain while preserving authorization for a provider domain hosting Web services. For example in a merger of two enterprises, Enterprise A and Enterprise B each enterprise would have had its own identity provider, but would like to share identities with minimum resources and no interruption to their existing security architectures after the merger. The present invention may be used to for identity bridging between Enterprise A and Enterprise B by using one of two credential source types: a SAML (Security Assertion Markup Language) Security assertion or an X.509 certificate.
For brevity, the generic “Trusted Gateway A” and “Federated Gateway B” references are used in all identity bridging examples, workflows, and instructions. The Trusted Gateway A is the certificate authority (CA) that issues and manages security credentials and that is responsible for authentication. The Federated Gateway B is the Web service provider that is responsible for authorization. The words “trusted” and “federated” are used from the point of view of the service requestor.
Referring to FIG. 20, there is shown the components of an identity bridging system which uses a SAML credential source. When used for identity bridging using an X.509 certificate credential source, the bridge does not have to submit the SAML token request to the trusted gateway A.
The required provider-side Gateway, known as the “Federated Gateway B,” is used for authorization in an identity-bridging configuration. The Federated Gateway B establishes a certificate-based trust relationship with the authentication source by importing trusted certificates into its trust store. The authentication source can be any certificate authority (CA) or another Gateway that acts as a CA.
When SAML is used as a credential source in an identity bridging-configuration, the authentication source must be able to issue a SAML token. If another Gateway is used as the credential source, then it is already able to issue a SAML token. The Federated Gateway B uses three types of federated identities for mediating requestor credentials: federated users, federated groups, and virtual groups it delegates authentication to one Gateway B.
The requestor-side Bridge is responsible for decorating request messages based on the Web service policy assertions defined in the Federated Gateway B. Decorated messages are sent from the Bridge to the Federated Gateway B for Web service authorization. If a policy contains a SAMLAssertion, then part of the Bridge's decorating task may involve getting a SAML token from the Trusted Gateway A during the initial connection or if the original SAML token has expired.
The Manager provides the interface for importing trusted certificates (CA certificates and/or server certificates extracted from the Trusted Gateway A) into the Federated Gateway B trust store. The Manager also provides the interface to configure and manage one or more Federated Identity Providers (FIPs), link trust store certificate(s) to FIPs, and configure the Federated Gateway B SAML policy.
In an identity bridging-configuration, the Federated Identity Provider (FIP) allows the Federated Gateway B (authorization domain) to authorize requests containing credentials originating in the Trusted Gateway A (authentication domain). Credentials may be X.509 certificates signed by trusted certificate authorities (CAs) or SAML tokens signed by a Gateway as shown in FIG. 20 or other LDAP Identity. Alternatively, a Federated Identity Provider may not contain any certificates.
The trust store in the Federated Gateway B is the repository for the certificates from other security domains that may be required by the FIP in an identity-bridging configuration. Certificates are defined and added to the trust store with the Add Certificate Wizard in the Manager prior to creating the FIP in the Federated Gateway B. The chosen credential source and optional configuration elements outlined determine certificate and FIP configuration details. Once the trusted certificates are added to a new FIP, federated users, groups, and/or virtual groups can be created to authorize corresponding users, groups, or credential patterns in the Federated Gateway B security domain. The Federated Identity Provider (FIP) is an element when bridging disparate security domains. The certificates that are used as the credential source in an FIP are defined and imported into the trust store using the Manager's Add Certificate Wizard.
The Manager's Create Federated Identity Provider Wizard is used to add an FIP to the Federated Gateway B. In the Wizard, you can define the type(s) of credential source(s) that the FIP will support, configure SAML credential source details, when applicable, and add trust store certificates.
Conclusion
Based on a scalable appliance model, the system provides architects and security administrators the foundation required to confidently federate shared Web services across external departments, business units, and partners.
The system 1100 tightly integrates with existing trust infrastructure including identity management, access control, and SSO products inside the provider and requestor security domains. This ensures continuity in existing local authentication and authorization processes and provides the foundation to bridge independent trust environments.
The system 1100 according to an embodiment of the present invention facilitates the separation of authentication and authorization operations to the appropriate security domains while ensuring coherence between both functions. Authentication is performed in the client domain where the client identity information resides, and authorization is performed in the provider domain where the shared Web services reside. Since the gateway 1104 and bridge 1110 establish an automated, PKI-based exchange of data, private identity information is never exposed or manually replicated between the requestor and provider domains. Protecting the exchange of identity information ensures uncompromised security even in today's challenging business and regulatory environment.
The system 1100 according to an embodiment of the present invention utilizes proven, interoperable SAML and WS-Security standards to securely exchange identities and authentication evidence. Advantageously the system is also easily adapted to accommodate new standards as these evolve.
Securely exchanging identity is critical to the successful integration of applications across identity silos. As information technology rationalization and productivity pressures move more companies towards Web services, more applications will be delivered as XML-based Web services to enable their reuse across diverse business processes. Since business processes often impact systems across multiple departments, business units, or partners, these Web services will require identity federation to ensure that authentication and authorization occur in the appropriate security domains. Although various disparate technologies have attempted to address these requirements, they fail to deliver a practical, flexible, and cost-effective solution for Web services.
While the present invention has been described with respect to specific examples including presently preferred modes of carrying out the embodiments, those skilled in the art will appreciate that there are numerous variations, permutations and combinations of the above described systems and techniques that fall within the spirit and scope of the matter as set forth in the appended claims.

## Claims

1. A system for securing web services on one or more server computers delivered to one or more client computers, comprising:
a. one or more policies stored on said one or more server computers that define rules that must be satisfied for a web service provided by said one or more server computers to be accessed by said one or more client computers;
b. an agent process residing on said one or more client computers;
c. a local authorization source residing on said one or more client computers; and
d. a gateway process residing on said one or more server computers, said agent process detects a refusal for said web service, said agent process requests and receives said one or more policies from said one or more server computers in response to detecting said refusal for said web service, said agent process caches said received one or more policies as a dynamically updateable policy on said one or more client computers, said agent process directly applies any policy changes received from said gateway process to said dynamically updateable policy, said agent process intercepts a service request message for said web service from said one or more client computers and determines an identity associated with said service request message, said agent process authenticates said identity using said local authorization source and acquires a security token from said local authorization source, said agent process decorates said service request message using said security token based on said dynamically updateable policy, said agent process transmits said decorated service request message to said one or more server computers, said gateway process receives said decorated service request message and verifies an authenticity of said security token, said gateway process authorizes access to said web service in response to said authenticity of said security token being verified, said gateway process authorizes access to said web service independent of said identity associated with said service request message.

2. A system as defined in claim 1, wherein said identity associated with said service request message corresponds with a user identity of a user requesting access to said web service.

3. A system as defined in claim 1, wherein said policies include a rule set.

4. A system as defined in claim 1, wherein said policies include an assertion.

5. A system as defined in claim 1, wherein said policies include message-rerouting information.

6. A system for bridging user identities between a first security domain and a second security domain, comprising:
a bridge residing within said first security domain, said bridge configured to intercept a service request message from a user in said first security domain for access to a web service in said second security domain, said user is associated with an identity, said bridge configured to authenticate said identity of said user and to bind a security token with said service request message;
a gateway network appliance residing within said second security domain, said gateway network appliance configured to receive said service request message and to verify an authenticity of said security token, said gateway network appliance configured to authorize access to said web service in response to said authenticity of said security token being verified, said gateway network appliance configured to authorize access to said web service independent of said identity of said user; and
an agent residing within said first security domain, said agent detects a refusal for said web service, said agent process requests and receives one or more logical expressions from said gateway network appliance in response to detecting said refusal for said web service, said agent configured to modify said service request message by applying said one or more logical expressions requested and received from said gateway network appliance according to a dynamically updateable policy received from said second security domain and stored at said agent, said agent configured to receive and apply directly from the gateway network appliance any policy changes.

7. The system of claim 6, wherein said one or more logical expressions include a rule set, said rule set demands that said service request message be encrypted using AES encryption.

8. The system of claim 6, wherein said one or more logical expressions include an assertion.

9. The system of claim 6, wherein said one or more logical expressions include message-rerouting information.

10. The system of claim 6, wherein said bridge authenticates said identity of said user using a local authorization source and acquires said security token from said local authorization source.

11. The system of claim 6, wherein said gateway network appliance comprises a gateway server.