The best way to enforce the principle of least privilege on a server containing data with different security classifications is to apply access controls determined by the data owner. The principle of least privilege states that users should only have the minimum level of access required to perform their tasks. The data owner is the person who has the authority and responsibility to classify, label, and protect the data according to its sensitivity and value. The data owner can define the access rightsand permissions for each user or role based on the data classification policy and the business needs. This will ensure that only authorized and appropriate users can access the data and prevent unauthorized or excessive access that could compromise the confidentiality, integrity, or availability of the data. References:
* CISA Review Manual (Digital Version)
* CISA Questions, Answers & Explanations Database

When reviewing an enterprise architecture (EA) department's decision to change a legacy system's components while maintaining its original functionality, an IS auditor should understand the current business capabilities delivered by the legacy system, as this would help to evaluate whether the change is justified, feasible, and aligned with the business goals and needs. The proposed network topology to be used by the redesigned system, the data flows between the components to be used by the redesigned system, and the database entity relationships within the legacy system are technical details that are less relevant for an IS auditor to understand when reviewing this decision. References: CISA Review Manual (Digital Version), Chapter 3, Section 3.2

The most useful metric for management to consider when reviewing a project portfolio is the net present value (NPV) of the portfolio. NPV is a measure of the profitability and value of a project or a portfolio of projects, taking into account the time value of money and the expected cash flows. NPV compares the present value of the future cash inflows with the present value of the initial investment and shows how much value is created or lost by undertaking a project or a portfolio of projects1. A positive NPV indicates that the project or portfolio is worth more than its cost and will generate a positive return on investment. A negative NPV indicates that the project or portfolio is worth less than its cost and will result in a loss. Therefore, NPV helps management to prioritize andselect the most profitable and valuable projects or portfolios that align with the organizational strategy and objectives2. The other options are less useful or incorrect because:
* A. Cost of projects divided by total IT cost is not a useful metric for reviewing a project portfolio, as it does not reflect the benefits, value, or return of the projects. It only shows the proportion of IT budget allocated to the projects, which may not be indicative oftheir strategic importance or alignment3.
* B. Expected return divided by total project cost is not a useful metric for reviewing a project portfolio, as it does not account for the time value of money and the timing of cash flows. It only shows the average return per unit of cost, which may not be comparable across different projects or portfolios with differentdurations, risks, and cash flow patterns4.
* D. Total cost of each project is not a useful metric for reviewing a project portfolio, as it does not reflect the benefits, value, or return of the projects. It only shows theinitial investment required for eachproject, which may not be indicative of their profitability or viability5. References: Portfolio, Program and Project Management Using COBIT 5 - ISACA, Project PortfolioManagement - ISACA, CISA Review Manual (Digital Version), Standards, Guidelines, Tools and Techniques