WebSphere Application Server Versions 6 and later include a number of enhancements for securing Web services. Policy sets, or assertions about services are defined, can be used to simplify your security configuration for Web services.
The Web services security runtime implementation that is used only by WebSphere Application Server is based on the IBM Web Service runtime. In turn, the IBM Web services runtime is based on the open source Axis Web Service engine with IBM enhancements. The application programming model is JAX-RPC (JSR-109). The open source Axis Web Service engine uses DOM as the document object model.
To assemble your applications and to specify the security constraints for Web services security in the deployment descriptor and bindings, it is recommended that you use an assembly tool. You can also use the WebSphere Application Server administrative console to edit the application binding file.
In
IBM WebSphere Application Server Version 6.1 Feature Pack for Web Services,
WebSphere Application Servers also uses another Web Services Security runtime,
which is new and based on the Java API for XML Web Services (JAX-WS) programming
model and the updated SAAJ programming model. Instead of deployment descriptor
and bindings, a policy set is used for configuration.
This JAX-WS programming model is substantially
different from the IBM Web services runtime implementation and the application
programming model JAX-RPC (JSR-109) that is used with previous WebSphere Application
Server versions. New enhancements include the flexibility to support different
message exchange patterns, asynchronous method invocation, an AXIOM data
model, and so forth.
In IBM WebSphere Application Server Version 6.1 Feature Pack for Web Services, policy sets can be used to simplify your Web service Quality of Service configuration.
In IBM WebSphere Application Server Version 6.1 Feature Pack for Web Services, Web Services Security Trust (WS-Trust) provides the ability for an endpoint to issue a security context token for Web Services Secure Conversation (WS-SecureConversation) . The token issuing support is limited to the security context token. Trust policy management defines a policy for each of the trust service operations, such as issuing, cancelling, validating, and renewing a token. A client's bootstrap policies must correspond to the WebSphere Application Server trust service policies.
In IBM WebSphere Application Server Version 6.1 Feature Pack for Web Services, Web Services Secure Conversation provides a secured session for long running message exchanges and leveraging symmetric cryptographic algorithm. WS-SecureConversation provides the basic security for securing session-based messages exchange patterns, such as Web Services Security Reliable Messaging (WS-ReliableMessaging). The symmetric cryptographic algorithm should provide better performance and throughput when compared to asymmetric cryptographic algorithm
Signature confirmation enhances XML digital signature security and provides message-level security that is more secure. The SignatureConfirmation element indicates that the responder has processed the signature in the request, and the signature confirmation ensures that the signature is indeed processed by the intended recipient. To process signature confirmation correctly, the initiator must preserve the signatures during the request generation processing and later must retrieve the signatures for confirmation checks even with the stateless nature of Web Service and the different message exchange patterns. You enable signature confirmation by configuring the policy.
The encrypted header element provides a standard way of encrypting SOAP headers, which helps inter-operability. As one of the extensions to the Organization for the Advancement of Structured Information Standards (OASIS) SOAP message security specification, the EncryptedHeader element indicates that a specific SOAP header (or set of headers) must be protected. Encrypting SOAP headers and parts helps to provide more secure message-level security. The EncryptedHeader element ensures compliance with the SOAP mustUnderstand processing guidelines and prevents disclosure of information contained in attributes on a SOAP header block.
The OASIS Web Services Security specification defines a generic mechanism to associate security tokens with a SOAP message. In WebSphere Application Server, the pluggable token framework is enhanced to handle this flexible mechanism. The pluggable token framework has been redesigned to allow the same implementation that is used for creating and validating a security token to also be used in the Web Service Security runtime. The redesigned framework simplifies the programming model and makes it easier to add new or custom security token types.
The following scenario briefly describes how to create a Username token and how to validate the Username token.
The OASIS Web Service Security (WS-Security) Version 1.1 support provides for a standard way of encrypting and signing SOAP headers. In the IBM WebSphere Application Server Version 6.1 Feature Pack for Web Services, to sign or encrypt SOAP messages, specify the QName to select header elements in the SOAP header of the SOAP message.
You can configure policy sets for signing or encrypting either by using the administrative console or by using Web Services Security APIs (WSS APIs).
For Web Services Security Version 1.0 behavior, specify the com.ibm.ws.wssecurity.encryptedHeader.generate.WSS1.0 property with a value of true in EncryptionInfo in the bindings. Specifying this property results in an EncryptedData element.
Lightweight Third Party Authentication (LTPA) is supported as a binary security token in Web services security. The token type is http://www.ibm.com/websphere/appserver/tokentype/5.0.2/LTPA.
You can insert a timestamp in other elements during the signing process besides the Web services security header. This timestamp provides a mechanism for adding a time limit to an element. This support is an extension for WebSphere Application Server. Other vendor implementations might not have the ability to consume a message that is generated with an additional timestamp that is inserted in the message.
You can insert a nonce, which is a randomly generated value, in other elements beside the Username token. The nonce is used to reduce the chance of a replay attack. This support is an extension for WebSphere Application Server. Other vendor implementations might not have the ability to consume messages with a nonce that is inserted into elements other than a Username token.
Distributed nonce caching is a new feature for Web services in WebSphere Application Server Versions 6 and later that enables you to replicate nonce data between servers in a cluster. For example, you might have application server A and application server B in cluster C. If application server A accepts a nonce with a value of X, then application server B creates a SoapSecurityException if it receives the nonce with the same value within a specified period of time.
WebSphere Application Server Version 6 and later cache the X.509 certificates it receives, by default, to avoid certificate path validation and improve its performance. However, this change might lead to security exposure. You can disable X.509 certificate caching by using the following steps: