Free SOA S90.20 Exam Dumps Questions & Answers

Services A, B, and C reside in Service Inventory A and Services D, E, and F reside in Service Inventory B.
Service B is an authentication broker that issues WS-Trust based SAML tokens to Services A and C upon receiving security credentials from Services A and
C. Service E is an authentication broker that issues WS-Trust based SAML tokens to Services D and F upon receiving security credentials from Services D and E.
Service B uses the Service Inventory A identify store to validate the security credentials of Services A and C.
Service E uses the Service Inventory B identity store to validate the security credentials of Services D and F.

To date, the two service inventories have existed independently from each other. However, a requirement has emerged that the services in Service Inventory A need to be able to use the services in Service Inventory B, and vice versa.
How can cross-service inventory message exchanges be enabled with minimal changes to the existing service inventory architectures and without introducing new security mechanisms?

• A.The current security mechanism already fulfills the requirement because SAML tokens can be used across multiple security domains. The only change required is for each authentication broker to be configured so that it issues service inventory-specific assertions for SAML tokens originating from other service inventories.
• B.Because SAML tokens cannot be used across multiple security domains, authentication brokers C and E need to be replaced with one single authentication broker so that one token issuer is used for all services across both of the service inventories.
• C.The Trusted Subsystem pattern is applied to encapsulate Services B and E using a central utility service that balances request and response messages exchanged between Services B and E, depending on which service inventory the messages originate from. The utility service also contains transformation logic to ensure that the SAML tokens issued by Services B and E are compatible. This guarantees that an issued SAML token can be used across Service Inventories A and B without further need for runtime conversion.
• D.The individual domain service inventories need to be combined into one enterprise service inventory. The Service Perimeter Guard pattern can be applied to establish a contact point for request messages originating from outside the service inventory. Within the service inventory, services no longer need to be authenticated because they are all part of the same trust boundary.

Service A exchanges messages with Service B multiple times during the same runtime service activity. Communication between Services A and B has been secured using transport-layer security. With each service request message sent to Service B (1A. IB), Service A includes an X.509 certificate, signed by an external Certificate Authority (CA).
Service B validates the certificate by retrieving the public key of the CA (2A. 2B) and verifying the digital signature of the X.509 certificate. Service B then performs a certificate revocation check against a separate external CA repository (3A, 3B). No intermediary service agents reside between Service A and Service B.

Service B has recently suffered from poor runtime performance plus it has been the victim of an access-oriented attack. As a result, its security architecture must be changed to fulfill the following new requirements: 1. The performance of security-related processing carried out by Service B when communicating with Service A must be improved. 2. All request messages sent from Service A to Service B must be screened to ensure that they do not contain malicious content.
Which of the following statements describes a solution that fulfills these requirements?

• A.Add a service agent to screen messages sent from Service A to Service B.
  The service agent can reject any message containing malicious content so that only verified messages are passed through to Service B.
  Instead of using X.509 certificates, use WS- SecureConversation sessions. Service A can request a Security Context Token (SCT) from a Security Token Service and use the derived keys from the session key to secure communication with Service B.
  Service B retrieves the session key from the Security Token Service.
• B.Eliminate the need to retrieve the public key from the Certificate Authority and to verify the certificate revocation information by extending the service contract of Service B to accept certificates only from pre-registered Certificate Authorities. This form of pre- registration ensures that Service B has the public key of the corresponding Certificate Authority.
• C.Apply the Trusted Subsystem pattern by introducing a new utility service between Service A and Service B.
  When Service A sends request messages, the utility service verifies the provided credentials and creates a customized security profile for Service A.
  The security profile contains authentication and access control statements that are then inherited by all subsequent request messages issued by Service A.
  As a result, performance is improved because Service A does not need to resubmit any additional credentials during subsequent message exchanged as part of the same runtime service activity. Furthermore, the utility service performs message screening logic to filter out malicious content.
• D.Apply the Trusted Subsystem pattern to by introducing a new utility service. Because Service B is required to limit the use of external resources. Service A must ensure that no other services can request processing from Service B in order to prevent malicious content from infiltrating messages. This is achieved by creating a dedicated replica of Service B to be used by the utility service only. Upon receiving the request message and the accompanying security credentials from Service A.
  the utility service verifies the authentication information and the validity of the X.509 signature. If the authentication information is correct, then the utility service replicates the code of Service B, performs the necessary processing, and returns the response to Service A.

Service A has two specific service consumers, Service Consumer A and Service Consumer B (1). Both service consumers are required to provide security credentials in order for Service A to perform authentication using an identity store (2). If a service consumer's request message is successfully authenticated, Service A processes the request by exchanging messages with Service B (3) and then Service C (4). With each of these message exchanges, Service A collects data necessary to perform a query against historical data stored in a proprietary legacy system. Service A's request to the legacy system must be authenticated (5). The legacy system only provides access control using a single account. If the request from Service A is permitted, it will be able to access all of the data stored in the legacy system. If the request is not permitted, none of the data stored in the legacy system can be accessed. Upon successfully retrieving the requested data (6), Service A generates a response message that is sent back to either Service Consumer A or B.
The legacy system is also used independently by Service D without requiring any authentication. Furthermore, the legacy system has no auditing feature and therefore cannot record when data access from Service A or Service D occurs. If the legacy system encounters an error when processing a request, it generates descriptive error codes.

This service composition architecture needs to be upgraded in order to fulfill the following new security requirements: 1. Service Consumers A and B have different access permissions and therefore, data received from the legacy system must be filtered prior to issuing a response message to one of these two service consumers. 2. Service Consumer A's request messages must be digitally signed, whereas request messages from Service Consumer B do not need to be digitally signed.
Which of the following statements describes a solution that fulfills these requirements?

• A.The Trusted Subsystem pattern is applied by introducing a utility service that encapsulates the legacy system. To support access by service consumers issuing request messages with and without digital signatures, policy alternatives are added to Service A's service contract. Service A authenticates the service consumer's request against the identity store and verifies compliance to the policy. Service A then creates a signed SAML assertion containing an authentication statement and the authorization decision. The utility service inspects the signed SAML assertions to authenticate the service consumer and then access the legacy system using a single account. The data returned by the legacy system is filtered by the utility service, according to the information in the SAML assertions.
• B.The Trusted Subsystem pattern is applied together with the Message Screening pattern by introducing a utility service that encapsulated the legacy system and contains message screening logic. First, the utility service evaluates the incoming request messages to ensure that it is digitally signed, when necessary. After successful verification the request message is authenticated, and Service A performs the necessary processing. The data returned from the legacy system is filtered by the utility service's message screening logic in order to ensure that only authorized data is returned to Service Consumers A and B.
• C.The Trusted Subsystem pattern is applied by introducing a utility service that encapsulates the legacy system. Two different policies are created for Service A's service contract, only one requiring a digitally signed request message. The utility service accesses the legacy system using the single account. Service A authenticates the service consumer using the identity store and, if successfully authenticated, Service A send a message containing the service consumer's credentials to the utility service. The identity store is also used by the utility service to authenticate request messages received from Service A.
  The utility service evaluates the level of authorization of the original service consumer and filters data received from the legacy system accordingly.
• D.The Trusted Subsystem pattern is applied by introducing a utility service that encapsulates the legacy system. After successful authentication, Service A creates a signed SAML assertion stating what access level the service consumer has. The utility service inspects the signed SAML assertion in order to authenticate Service A.
  The utility service accesses the legacy system using the account information originally provided by Service Consumer A or B.
  The utility service evaluates the level of authorization of the original service consumer and filters data received from the legacy system accordingly.

Service A is a publically accessible service that provides free multimedia retrieval capabilities to a range of service consumers. To carry out this functionality, Service A is first invoked by Service Consumer A (1). Based on the nature of the request message received from Service Consumer A, Service A either invokes Service B or Service C.
When Service B is invoked by Service A (2A) it retrieves data from publicly available sources (not shown) and responds with the requested data (3A). When Service C is invoked by Service A (2B) it retrieves data from proprietary sources within the IT enterprise (not shown) and responds with the requested data (3B). After receiving a response from Service B or Service C, Service A sends the retrieved data to Service Consumer A (4).
Service B does not require service consumers to be authenticated, but Service C does require authentication of service consumers. The service contract for Service A therefore uses WS-Policy alternative policies in order to express the two different authentication requirements to Service Consumer A.
When Service Consumer A sends a request message (1), Service A determines whether the request requires the involvement of Service C and then checks to ensure that the necessary security credentials were received as part of the message. If the credentials provided by Service Consumer A are verified. Service A creates a signed SAML assertion and sends it with the request message to Service C (2B) This authentication information is protected by public key encryption However, responses to Service Consumer A's request message (3B, 4) are not encrypted for performance reasons.

Recently, the usage of Service C has noticeably declined. An investigation has revealed response messages issued by Service C (3B) have been repeatedly intercepted and accessed by unauthorized and malicious intermediaries. As a result, Service Consumer A has lost confidence in the use of Service A for the retrieval of proprietary data because it is being viewed as a security risk. This is especially troubling, because the owner of Service A had planned to start charging a fee for Service A's ability to provide proprietary data via the use of Service C.
How can this service composition architecture be changed to address the security problem with minimal impact on runtime performance?

• A.Use the existing PKI to establish secure communication between Service Consumer A and Service C.
  A symmetric key can be generated for the data being sent from Service C to Service Consumer A Service C can generate a session key that is encrypted with Service Consumer A's public key. Service C can then attach the session key to the response message, which is encrypted using the session key. Because only Service Consumer A can decrypt the encrypted session key, the data transmitted in the message is safe from access by unauthorized intermediaries.
• B.Use the existing PKI to provide message-layer security for the response messages originating from Service C.
  To provide message confidentiality, Service C can encrypt the response messages using Service Consumer A's public key. This prevents unauthorized intermediaries from accessing the content of response messages.
• C.Use the existing PKI to specify encryption and digital signature requirements on the messages. Service C can use Service Consumer A's public key to generate a symmetric key. Service Consumer A can also generate the same session key from its own public key.
  Service C can use the session key to encrypt the response message (and the hash value of the response message), concatenate them, and send them to Service Consumer A.
  Service Consumer A separates the concatenated and encrypted hash value, decrypts it, and then decrypts the encrypted response message. As a result, the confidentiality and integrity of the response message are guaranteed.
• D.Use the existing PKI to provide two-way authentication of the exchanged messages.
  After receiving a request from the service consumer, Service A can respond with a signed acknowledgement of the message, encrypted by the public key of Service Consumer A.
  Only Service Consumer A will be able to decrypt the encrypted acknowledgement. Service Consumer A then responds to the acknowledgement, thereby verifying its identity with Service A.
  Because both Service Consumer A and Service A are mutually authenticated, end-to-end transport-layer security is sufficient to provide message confidentiality in order to prevent unauthorized intermediaries from accessing messages originating from Service C.