Arcitura Education SOA Security Lab S90.20 Exam Practice Test

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Total 30 questions

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Question 1

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?

AThe 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 .

BMessages 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.

CApply 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 .

DApply 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 .

Answer : A

Question 2

Service A provides a data access capability that can be used by a variety of service consumers. The database records accessed by Service A are classified as either private or public. There are two types of service consumers that use Service A:

Service consumers with public access permissions (allowed to access only public data records) and service consumers with private access permissions (allowed to access all data records). For performance reasons the Service A architecture uses a single database, named Database A .Each record in Database A is classified as either private or public. After Service A is invoked by a service consumer (1), it authenticates the request message using an identity store and retrieves the corresponding authorization (2, 3). Once authorized, the service consumer's request is submitted to Database A (4), which then returns the requested data (5) If the service consumer has private access permissions, all of the returned data is included in Service A's response message (6). If the service consumer has public access permissions, then Service A first filters the data in order to remove all unauthorized private data records, before sending to the response message to the service consumer (6). An investigation recently detected that private data has been leaked to unauthorized service consumers. An audit of the Service A architecture revealed that Service A's filtering logic is flawed, resulting in situations where private data was accidentally shared with service consumers that only have public access permissions. Further, it was discovered that attackers have been monitoring response messages sent by Service A in order to capture private data. It is subsequently decided to split Database A into two databases:

one containing only private data (the Private Database) and the other containing only public data (the Public Database). What additional changes are necessary to address these security problems?

AThe Service A logic needs to be modified to work with the two new databases. Service A needs to be able to access the Public Database and the Private Database when it receives a request message from a service consumer with private access permissions, and it must only access the Public Database when it receives a request message from a service consumer with public access permissions. Furthermore, any response messages issued by Service A containing private data need to be encrypted.

BA utility service needs to be created and positioned between Service A and the service consumer. The utility service can-contain screening logic that can verify the service consumer's credentials and then forward the request message to the Private Database or to the Public Database, depending on the service consumer's access permissions. Because each request message is evaluated by the database, no filtering of the returned data is necessary. The data is sent back to the consumer in a response message encrypted using symmetric key encryption.

CAfter the service consumer's request message is authenticated. Service A can generate a onetime symmetric encryption key that it sends to the service consumer. This key is encrypted by the public key of the service consumer. After the service consumer acknowledges the receipt of the one-time encryption key, Service A forwards the service consumer's data access request (and the corresponding credentials) to both databases. After receiving the responses from the databases, Service A compiles the results into a single response message. This message is encrypted with the one-time key and sent by Service A to the service consumer.

DThe Service A architecture can be enhanced with certificate-based authentication of service consumers in order to avoid dependency on the identity store. By using digital certificates, Service A can authenticate a service consumer's request message and then forward the data access request to the appropriate database. After receiving the responses from the databases, Service A can use the service consumer's public key to encrypt the response message that is sent to the service consumer.

Answer : A

Question 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?

AApply 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.

BApply 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 .

CAll 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.

DApply 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.

Answer : B

Question 4

Services A and B use digital certificates to support message integrity and authentication. With every message exchange between the two services (2, 5, 6, 8), the digital certificates are used. It has been determined that both Databases A and B are vulnerable to malicious attackers that may try to directly access sensitive data records. Furthermore, performance logs have revealed that the current exchange of digital certificates between Services A and B is unacceptably slow. How can the integrity and authenticity of messages exchanged between Services A and B be maintained, but with improved runtime performance - and - how can Databases A and B be protected with minimal additional impact on performance?

AApply the Brokered Authentication pattern to establish an authentication broker that uses WS-Trust based SAML tokens for message exchanges between Services A and B .This eliminates the need for Service A to be repeatedly authenticated by Service B .Use the public key of Service A to encrypt Database A and use the public key of Service B to encrypt Database B.

BApply the Brokered Authentication pattern to establish an authentication broker that uses WS-Secure-Conversation Security-context tokens (SCTs) to generate and transmit a symmetric session key. The session key is used to encrypt and digitally sign messages exchanged between Services A and B .For each database the Trusted Subsystem pattern is applied to require authenticated access to the database and to prevent attackers from accessing the database directly

CApply the Direct Authentication pattern to establish mutual authentication between Services A and B using a shared identity store. Service A attaches a Username token to the first request message sent to Service B and Service B authenticates the request message using the shared identity store. Similarly, when Service B submits a response message to Service A .it attaches its own Username token that Service A then authenticates by also using the same shared identity-store. Database A is encrypted using the Service A password as a secret encryption key and Database B is encrypted using the Service B password as a secret encryption key.

DApply the Brokered Authentication pattern to establish an authentication broker that uses WS-Trust based SAML tokens for message exchanges between Services A and B .This eliminates the need for Service A to be repeatedly authenticated by Service B .Database A is encrypted using the Service A password as a secret encryption key and Database B is encrypted using the Service B password as a secret encryption key.

Answer : B

Question 5

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?

AIn 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.

BA 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 .

CThe 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 .

DDue 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 .

Answer : C

Question 6

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?

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

BApply 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.

CApply 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 .

DThe 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.

Answer : B

Question 7

Service Consumer A sends a request to Service A (1). Service A replies with an acknowledgement message (2) and then processes the request and sends a request message to Service B (3). This message contains confidential financial data. Service B sends three different request messages together with its security credentials to Services C, D, and E (4, 5, 6). Upon successful authentication, Services C, D, and E store the data from the message in separate databases (7, 8, 9) Services B, C, D, and E belong to Service Inventory A, which further belongs to Organization B .Service Consumer A and Service A belong to Organization A .The service contracts of Services A and B both comply with the same XML schema. However, each organization employs different security technologies for their service architectures. To protect the confidential financial data sent by Service A to Service B, each organization decides to independently apply the Data Confidentiality and the Data Origin Authentication patterns to establish message-layer security for external message exchanges. However, when an encrypted and digitally signed test message is sent by Service A to Service B, Service B was unable to decrypt the message. Which of the following statements describes a solution that solves this problem?

AAlthough both of the organizations applied the Data Confidentiality and the Data Origin Authentication patterns, the security-technologies used for the Service A and Service B architectures may be incompatible. Because there are several technologies and versions of technologies that can be used to apply these patterns, the organizations need to standardize implementation level details of the relevant security technologies.

BThe problem with the test message occurred because Service A used incorrect keys to protect the message sent to Service B .Service A used its own public key to sign the message and then used Service B's public key to encrypt the message content. To correct the problem, Service A must use WS-Secure-Conversation to agree on a secret session key to be used to encrypt messages exchanged between Services A and B .Because this session key is only known by Services A and B, encrypting the messages with this key also provides authentication of the origin of the data.

CAlthough both of the organizations successfully applied the Data Confidentiality and the Data Origin Authentication patterns, the order in which the patterns were applied is incorrect. The application of the Data Origin Authentication pattern must always follow the application of the Data Confidentiality pattern to ensure that the message confidentiality from a third party authenticates the origin of the message.

DThe problem with the test message occurred because Service A needed the private key of Service B to digitally sign the-message. An attacker pretending to be Service B likely sent a fake private/public keys pair to Service A .Using these fake keys to encrypt and digitally sign the message made the message incompatible for Service B .Because the fake private key was also used to sign the hash, it explains the source of the problem.

Answer : A