S90.20試験無料問題集（30題）「SOA Security Lab 認定」

出題：1

Service A provides a data retrieval capability that can be used by a range of service consumers, including Service Consumer A.
In order to retrieve the necessary data, Service Consumer A first sends a request message to Service A (1). Service A then exchanges request and response messages with Service B (2, 3), Service C (4, 5), and Service D (6.
7). After receiving all three response messages from Services B.
C. and D, Service A assembles the collected data into a response message that it returns to Service Consumer A (8).

The owner of Service A charges service consumers for each usage of the data retrieval capability. Recently, the owner of Service Consumer A has complained that the data returned by Service A is incorrect, incomplete, and from invalid sources. As evidence, the Service Consumer A owner has presented the owner of Service A with sample messages containing the incorrect and incomplete contents. As a result, the Service Consumer A owner has refused to pay the usage fees. Subsequent to an internal investigation, the owner of Service A determines that the data returned by Service A is consistently correct and complete. There are suspicions that the Service Consumer A owner is altering the original messages and issuing these complaints fraudulently in order to avoid paying the usage fees.
How can the owner of Service A prove that Service A is returning correct and complete data and that this data originated from the correct sources?

A. The service contract of Service A can be extended with an ignorable WS-Policy assertion that states that all request and response messages are logged by Service A and that false complaints will be prosecuted.

B. Apply the Brokered Authentication pattern to send the security credentials of Service Consumer A to Services B, C, and D.
Service A can carry out the brokered authentication logic and therefore act as the intermediary security broker. Upon receiving Service Consumer A's request message, Service A can further verify the credentials against an external certificate authority, if the request is authenticated. Service A can create a signed SAML assertion containing Service Consumer A's credentials and the authorization information. Service A then forwards the original request message and the signed SAML assertion to Services B, C, and D.

C. Apply the Data Origin Authentication pattern to verily that request and response messages exchanged by Service Consumer A and Service A and exchanged by Service A and Services B, C, and D originated from the claimed sources and have not been altered prior to transmission. Also, enhance the Service A architecture so that all messages sent to its service consumers are logged.

D. Apply the Data Origin Authentication and the Data Confidentiality patterns to ensure that request and response messages exchanged between Service A and Services B.
C, and D are digitally signed and encrypted. This guarantees message integrity and confidentiality.

正解：C 解答を投票する

出題：2

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 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.

B. 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.

C. 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.

D. 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.

正解：C 解答を投票する

出題：3

Service A provides a data retrieval capability that can be used by a range of service consumers, including Service Consumer A, In order to retrieve the necessary data. Service Consumer A first sends a request message to Service A (1). Service A then exchanges request and response messages with Service B (2, 3). Service C (4, 5), and Service D (6.
7). After receiving all three response messages from Services B.
C. and D, Service A assembles the collected data into a response message that it returns to Service Consumer A (8).

The Service A data retrieval capability has been suffering from poor performance, which has reduced its usefulness to Service Consumer A.
Upon studying the service composition architecture, it is determined that the performance problem can be partially attributed to redundant validation by service contracts for compliance to security policies. Services B and C have service contracts that contain the same two security policies. And, Service D has a service contract that contains a security policy that is also part of Service A's service contract.
What changes can be made to the service contracts in order to improve the performance of the service composition while preserving the security policy compliance requirements?

A. Apply the Policy Centralization pattern in order to establish two centralized policy definitions and ensure that policy enforcement logic is correspondingly centralized. The first policy definition includes the redundant security policies from Services A and D and the second policy definition contains the redundant security policies from Services B and C.

B. Apply the Standardized Service Contract principle in order to remove redundancy within service contracts by ensuring that all four service contracts comply with the same policy standards. This further requires the application of the Service Abstraction principle to guarantee that policy definitions are sufficiently streamlined for performance reasons.

C. Apply the Policy Centralization pattern in order to establish a single security policy for the entire service composition. The redundant policies residing in the service contracts of Services A.
B, C and D need to be removed and grouped together into one master policy definition enforced by Service A.
This way, redundant policy validation is eliminated, thereby improving runtime performance.

D. All policies are analyzed for similarities, which are then extracted and, by applying the Policy Centralization pattern, combined into a single policy definition. This "meta-policy" is then positioned to perform validation of the response message generated by Service A, prior to receipt by Service Consumer A.
If validation fails, an alternative error message is sent to Service Consumer A instead.

正解：A 解答を投票する

S90.20試験無料問題集「SOA Security Lab 認定」