S90.20 試験問題を無料オンラインアクセス

Service Consumer A sends a request message to Service A (1), after which Service A sends a request message with security credentials to Service B (2). Service B authenticates the request and, if the authentication is successful, writes data from the request message into Database B (3). Service B then sends a request message to Service C (4), which is not required to issue a response message. Service B then sends a response message back to Service A (5). After processing Service B's response, Service A sends another request message with security credentials to Service B (6). After successfully authenticating this second request message from Service A, Service B sends a request message to Service D (7). Service D is also not required to issue a response message. Finally, Service B sends a response message to Service A (8), after which Service A records the response message contents in Database A (9) before sending its own response message to Service Consumer A (10).

To use Service A, Service Consumer A is charged a per usage fee. The owner of Service Consumer A has filed a complaint with the owner of Service A, stating that the bills that have been issued are for more usage of Service A than Service Consumer A actually used.
Additionally, it has been discovered that malicious intermediaries are intercepting and modifying messages being sent from Service B to Services C and D.
Because Services C and D do not issue response messages, the resulting errors and problems were not reported back to Service B.
Which of the following statements describes a solution that correctly addresses these problems?

• A.Apply the Brokered Authentication to establish an authentication broker between Service Consumer A and Service A that can carry out the Kerberos authentication protocol. Before invoking Service A, Service Consumer A must request a ticket granting ticket and then it must request service granting tickets to all services in the service composition, including Services C and D.
  Messages sent by Service B to Services C and D must further be encrypted with the public key of Service Consumer A.
• B.The Data Confidentiality and Data Origin Authentication patterns need to be applied in order to establish message-layer confidentiality and integrity for messages sent to Services C and D.
  The Direct Authentication pattern can be applied to require that service consumer be authenticated in order to use Service A.
• C.Messages sent to Services C and D must be protected using transport-layer encryption in order to ensure data confidentiality. Service consumers of Service A must be authenticated using X.509 certificates because they can be reused for several request messages.
• D.Apply the Service Perimeter Guard and the Message Screening patterns together to establish a perimeter service between Service Consumer A and Service A.
  The perimeter service screens and authenticates incoming request messages from Service Consumer A.
  After successful authentication, the perimeter service generates a signed SAML assertion that is used by the subsequent services to authenticate and authorize the request message and is also carried forward as the security credential included in messages sent to Services C and D.

Service Consumer A sends a request message to Service A (1) after which Service A retrieves financial data from Database A (2). Service A then sends a request message with the retrieved data to Service B (3). Service B exchanges messages with Service C (4) and Service D (5), which perform a series of calculations on the data and return the results to Service A.
Service A uses these results to update Database A (7) and finally sends a response message to Service Consumer A (8). Component B has direct, independent access to Database A and is fully trusted by Database A.
Both Component B and Database A reside within Organization A.
Service Consumer A and Services A, B, C, and D are external to the organizational boundary of Organization A.

Component B is considered a mission critical program that requires guaranteed access to and fast response from Database A.
Service A was recently the victim of a denial of service attack, which resulted in Database A becoming unavailable for extended periods of time (which further compromised Component B). Additionally, Services B, C, and D have repeatedly been victims of malicious intermediary attacks, which have further destabilized the performance of Service A.
How can this architecture be improved to prevent these attacks?

• A.Service Consumer A generates a private/public key pair and sends this public key and identity information to Service A.
  Service A generates its own private/public key pair and sends it back to Service Consumer A.
  Service Consumer A uses the public key of Service A to encrypt a randomly generated session key and then sign the encrypted session key with the private key. The encrypted, signed session key is sent to Service A.
  Now, this session key can be used for secure message-layer communication between Service Consumer A and Service A.
  The Service Perimeter Guard pattern is applied to establish a perimeter service that encapsulates Database A in order to authenticate all external access requests.
• B.The Direct Authentication pattern is applied so that when Service Consumer A submits security credentials, Service A will be able to evaluate the credentials in order to authenticate the request message. If the request message is permitted, Service A invokes the other services and accesses Database A.
  Database A is replicated so that only the replicated version of the database can be accessed by Service A and other external service consumers.
• C.A utility service is created to encapsulate Database A and to assume responsibility for authenticating all access to the database by Service A and any other service consumers.
  Due to the mission critical requirements of Component B, the utility service further contains logic that strictly limits the amount of concurrent requests made to Database A from outside the organizational boundary. The Data Confidentiality and Data Origin Authentication patterns are applied to all message exchanged within the external service composition in order to establish message-layer security.
• D.Services B, C, and D randomly generate Session Key K, and use this key to encrypt request and response messages with symmetric encryption. Session Key K is further encrypted itself asymmetrically. When each service acts as a service consumer by invoking another service, it decrypts the encrypted Session Key K and the invoked service uses the key to decrypt the encrypted response. Database A is replicated so that only the replicated version of the database can be accessed by Service A and other external service consumers.

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.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.
• B.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.
• C.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.
• 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 Consumer A sends a request message with an authentication token to Service A, but before the message reaches Service A, it is intercepted by Service Agent A (1). Service Agent A validates the security credentials and also validates whether the message is compliant with Security Policy A.
If either validation fails, Service Agent A rejects the request message and writes an error log to Database A (2A). If both validations succeed, the request message is sent to Service A (2B).
Service A retrieves additional data from a legacy system (3) and then submits a request message to Service B Before arriving at Service B, the request message is intercepted by Service Agent B (4) which validates its compliance with Security Policy SIB then Service Agent C (5) which validates its compliance with Security Policy B.
If either of these validations fails, an error message is sent back to Service A.
that then forwards it to Service Agent A so that it the error can be logged in Database A (2A). If both validations succeed, the request message is sent to Service B (6). Service B subsequently stores the data from the message in Database B (7).
Service A and Service Agent A reside in Service Inventory A.
Service B and Service Agents B and C reside in Service Inventory B.
Security Policy SIB is used by all services that reside in Service Inventory B.
Service B can also be invoked by other service consumers from Service Inventory B.
Request messages sent by these service consumers must also be compliant with Security Policies SIB and B.

Access to the legacy system in Service Inventory A is currently only possible via Service A, which means messages must be validated for compliance with Security Policy A.
A new requirement has emerged to allow services from Service Inventory B to access the legacy system via a new perimeter service that will be dedicated to processing request messages from services residing in Service Inventory B.
Because the legacy system has no security features, all security processing will need to be carried out by the perimeter service.
However, there are parts of Security Policy A that are specific to Service A and do not apply to the legacy system or the perimeter service. Furthermore, response messages sent by the perimeter service to services from Service Inventory B will still need to be validated for compliance to Security Policy B and Security Policy SIB.
How can the Policy Centralization pattern be correctly applied without compromising the policy compliance requirements of services in both service inventories?

• A.In order for Security Policy A to be centralized so that it can be shared by Service A and the new perimeter service, messages sent to the perimeter service from services in Service Inventory B will need to continue complying with Security Policy A, even if it requires that the messages contain content that does not relate to accessing the legacy system. In order to centralize Security Policy B it will need to be combined with Security Policy SIB, which means that the functionality within Service Agents B and C can be combined into a single service agent.
• B.Due to the amount of overlap among Security Policy A, Security Policy B, and Security Policy SIB, the Policy Centralization pattern cannot be correctly applied to enable the described message exchange between the perimeter service in Service Inventory A and services in Service Inventory B.
• C.A single centralized security policy can be created by combining Security Policy A, Security Policy B.
  and Security Policy SIB into a single security policy that is shared by services in both Service Inventory A and Service Inventory B.
  This means that the new perimeter service can share the same new security policy with Service A.
  This further simplifies message exchange processing because request messages sent by services in Service Inventory B to the new perimeter service need to comply to the same security policy as the response messages sent back by the perimeter service to the services in Service Inventory B.
• D.The parts of Security Policy A that are required for access to the new perimeter service need to be removed and placed into a new security policy that is shared by Service A and the perimeter service. Messages sent by services accessing the perimeter service from Service Inventory B will need to be compliant with the new security policy. Because the perimeter service is dedicated to message exchange with services from Service Inventory B, response messages sent by the perimeter service can be designed for compliance to Security Policy B and Security Policy SIB.