Section: Protection of Information Assets
Explanation:
Deriving lower level policies from corporate policies {a top-down approach) aids in ensuring consistency
across the organization and consistency with other policies. The bottom-up approach to the development of
operational policies is derived as a result of risk assessment. A top-down approach of itself does not
ensure compliance and development does not ensure that policies are reviewed.

Attribute sampling is a method of audit sampling that is used to test the effectiveness of controls by measuring the rate of deviation from a prescribed procedure or attribute. Attribute sampling is suitable for testing compliance with the data center's physical access log system, as the auditor can compare the identification document numbers and photos of the visitors with the records in the system and determine whether there are any discrepancies or errors. Attribute sampling can also provide an estimate of the deviation rate in the population and allow the auditor to draw a conclusion about the operating effectiveness of the control.
Variable sampling, on the other hand, is a method of audit sampling that is used to estimate the amount or value of a population by measuring a characteristic of interest, such as monetary value, quantity, or size.
Variable sampling is not appropriate for testing compliance with the data center's physical access log system, as the auditor is not interested in estimating the value of the population, but rather in testing whether the system is operating as intended.
Quota sampling and haphazard sampling are both examples of non-statistical sampling methods that do not use probability theory to select a sample. Quota sampling involves selecting a sample based on certain criteria or quotas, such as age, gender, or location. Haphazard sampling involves selecting a sample without any specific plan or method. Both methods are not suitable for testing compliance with the data center's physical access log system, as they do not ensure that the sample is representative of the population and do not allow the auditor to measure the sampling risk or project the results to the population.
Therefore, attribute sampling is the most useful sampling method for an IS auditor conducting compliance testing for the effectiveness of the data center's physical access log system.
References:
* Audit Sampling - What Is It, Methods, Example, Advantage, Reason
* ISA 530: Audit sampling | ICAEW

The most appropriate IS audit recommendation for a bank that wants to outsource a system to a cloud provider residing in another country is to ensure the provider's internal control system meets bank requirements. This is because the cloud provider will be handling the bank's data, so it is important to ensure that the provider has appropriate controls in place to protect the data and to ensure its integrity. Additionally, the provider should have policies and procedures in place to ensure the security and privacy of the data, as well as to ensure compliance with applicable laws and regulations. For more information, please refer to the ISACA CISA Study Guide section 4.13.2.2.

Explanation
The most effective control for protecting the confidentiality and integrity of data stored unencrypted on virtual machines is to monitor access to stored images and snapshots of virtual machines. Images and snapshots are copies of virtual machines that can be used for backup, restoration, or cloning purposes. If data stored on virtual machines are unencrypted, they may be exposed or compromised if unauthorized or malicious users access or copy the images or snapshots. Therefore, monitoring access to stored images and snapshots can help detect and prevent any unauthorized or suspicious activities, and provide audit trails for accountability and investigation.
Restricting access to images and snapshots of virtual machines, limiting creation of virtual machine images and snapshots, and reviewing logical access controls on virtual machines regularly are not the most effective controls for protecting the confidentiality and integrity of data stored unencrypted on virtual machines. These controls may help reduce the risk or impact of data exposure or compromise, but they do not provide sufficient visibility or assurance of data protection. Restricting access to images and snapshots may not prevent authorized users from abusing their privileges or credentials. Limiting creation of virtual machine images and snapshots may not address the existing copies that may contain sensitive data. Reviewing logical access controls on virtual machines regularly may not reflect the actual access activities on images and snapshots.

The most important thing for the IS auditor to determine in a post-implementation review of a recently purchased system is whether the user requirements were met. User requirements are the specifications and expectations of the users of the system, such as the features, functions, performance, quality, and security of the system. User requirements are usually defined and documented in the early stages of the system acquisition process, such as in the request for proposal (RFP) or the contract. User requirements are also used as the basis for testing and evaluating the system before and after implementation.
Determining whether the user requirements were met can help the IS auditor assess whether the system is fit for purpose and delivers value and benefits to the users and the organization. Determining whether the user requirements were met can also help the IS auditor identify any gaps, issues, or problems with the system that may affect its functionality, usability, or reliability. Determining whether the user requirements were met can also help the IS auditor provide feedback and recommendations for improvement or enhancement of the system.
Stakeholder expectations were identified is not the most important thing for the IS auditor to determine in a post-implementation review of a recently purchased system, but rather a prerequisite or input for it.
Stakeholder expectations are the needs and wants of the various parties who have an interest or influence in the system, such as users, managers, customers, suppliers, regulators, or auditors. Stakeholder expectations are usually identified and analyzed in the initial stages of the system acquisition process, such as in the feasibility study or the business case. Stakeholder expectations are also used as inputs for defining and prioritizing the user requirements.
Vendor product offered a viable solution is not the most important thing for the IS auditor to determine in a post-implementation review of a recently purchased system, but rather an outcome or result of it. Vendor product is the system that is provided by an external supplier or service provider to meet the user requirements. Vendor product offered a viable solution means that the vendor product satisfied or exceeded the user requirements and delivered value and benefits to the users and organization. Vendor product offered a viable solution can be determined by comparing and evaluating the user requirements and the vendor product performance and quality.
Test scenarios reflected operating activities is not the most important thing for the IS auditor to determine in a post-implementation review of a recently purchased system, but rather a factor or criterion for it. Test scenarios are sets of conditions or situations that are used to test and verify whether the system meets the user requirements. Test scenarios reflected operating activities means that test scenarios simulated or replicated real-world scenarios that occur during normal operations of business processes or functions that use or depend on the system. Test scenarios reflected operating activities can help ensure that test results are valid, reliable, and relevant.
References:
Post Implementation Review: How to conduct and its Benefits 1
Post-implementation reviews - Department of Prime Minister and Cabinet 2 How To Conduct A Post Implementation Audit of Your RecentlyInstalled System 3