SOA Security Lab (S90.20) Free Practice Test

Question 1

Service Consumer A submits a request message with security credentials to Service A (1).
The identity store that Service A needs to use in order to authenticate the security credentials can only be accessed via a legacy system that resides in a different service inventory. Therefore, to authenticate Service Consumer A, Service A must first forward the security credentials to the legacy system (2). The legacy system then returns the requested identity to Service A (3). Service A authenticates Service Consumer A against the identity received from the legacy system. If the authentication is successful, Service A retrieves the requested data from Database A (4), and returns the data in a response message sent back to Service Consumer A (5).
Service A belongs to Service Inventory A which further belongs to Security Domain A and the legacy system belongs to Service Inventory B which further belongs to Security Domain
B. (The legacy system is encapsulated by other services within Service Inventory B, which are not shown in the diagram.) These two security domains trust each other.
Communication between Service A and the legacy system is kept confidential using transport-layer security.

No intermediary service agents currently exist between the two service inventories.
However, it has been announced that due to the introduction of new systems, some intermediary service agents may be implemented in the near future. Additionally, the legacy system has been scheduled for retirement and will be replaced by a new identity management system that will provide a new identity store. Because the new identity store will need to serve many different systems, there are concerns that it could become a performance bottleneck. As a result, services (including Service A and other services in Security Domains A and B) will not be allowed to directly access the new identity store.
Which of the following statements describes a solution that can accommodate the requirements of the new identity store, the authentication requirements of Service A, and can further ensure that message exchanges between Security Domains A and B remain confidential after intermediary service agents are introduced?

A. Apply the Trusted Subsystem pattern to implement a utility service abstracting the new identity management system. Service A forwards Service Consumer As credentials to the utility service to verify Service Consumer As identity. The utility service authenticates the request originating from Service A.
After successful authentication, the utility service uses its own credentials to retrieve the requested identity, and then send the identity to Service A, Therefore, effectively reducing the processing need of the identity management system.
The current transport-layer security can still be used, in order to secure the communication between Service A and the new utility service, as it more efficient than the message-layer security.

B. Replicate the identity database used by the new identity management system. Because the Security Domains A and B trust each other, protection of the identity store is guaranteed. Use Service Agents to monitor changes to the identity database used by the new identity management system and to update the replica. This would satisfy the security needs of Service A, would eliminate the need to request services from Service Inventory B, and ensure that current identity information is available for Service A.
Because Service A would not need to access services across different trust domains, the current transport- layer security is sufficient.

C. Apply the Trusted Subsystem pattern by abstracting away the new identity management system using a utility service that authenticates the request from Service A and then uses its own credentials to retrieve the requested identity from the new identity management system. For the utility service to authenticate Service As request, it needs to be provisioned with a new identity database that contains identities for all authorized service consumers of the new utility service. In order to secure the communication between Service A and the new utility service, use message-layer security as it provides security over multiple hops considering the need to secure the message in case an intermediary is introduced in future.

D. Apply the Brokered Authentication pattern to establish an authentication broker. Instead of Service A directly authenticating Service Consumer A, Service Consumer A submits a request message with security credentials to the authentication broker, which authenticates Service Consumer A against the new identity store and then issues a SAML token to Service Consumer A that it can use for message exchanges with other services, if necessary. In order to secure cross-service inventory message exchanges, the Data Confidentiality pattern is applied to establish message-layer security.

Correct Answer: D

Question 2

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.

Correct Answer: A

Question 3

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 from within Service Inventory B.
Request messages sent by these service consumers must also be compliant with Security Policies SIB and B.

New services are being planned for Service Inventory A.
To accommodate service inventory-wide security requirements, a new security policy (Security Policy SIA) has been created. Compliance to Security Policy SIA will be required by all services within Service Inventory A.
Some parts of Security Policy A and Security Policy SIB are redundant with Security Policy SIA.
How can the Policy Centralization pattern be correctly applied to Service Inventory A without changing the message exchange requirements of the service composition?

A. The parts of Security Policy A and Security Policy SIB that are redundant with Security Policy SIA are removed so that there is no overlap among these three security policies.
Service Agent A is updated so that it can validate messages for compliance with both Security Policy A and Security Policy SIA. Service Agent B is updated so that it can validate messages for compliance with both Security Policy SIA and Security Policy SIB.
Service Agent C remains unchanged.

B. Due to the amount of overlap among Security Policy A, Security Policy SIA, and Security Policy SIB, the Policy Centralization pattern cannot be correctly applied without changing the message exchange requirements of the service composition.

C. The parts of Security Policy A that are redundant with Security Policy SIA are removed so that there is no overlap between these two security policies. A new service agent is introduced into Service Inventory A to validate compliance to the new Security Policy SIA prior to messages being validated by Service Agent A.

D. The parts of Security Policy A and Security Policy SIB that are redundant with Security Policy SIA are removed so that there is no overlap among these three security policies. A new service agent is introduced into Service Inventory A to validate compliance to the new Security Policy SIA prior to messages being validated by Service Agent A.
Another new service agent is introduced into Service Inventory B to validate compliance to the new Security Policy SIA prior to messages being validated by Service Agents B and C.

Correct Answer: C

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SOA Security Lab (S90.20) Free Practice Test