The primary role of a data custodian in the risk management process is to ensure that data is protected according to the classification. A data custodian is a person or entity that has the responsibility for implementing and maintaining the security controls for the data, such as access rights, encryption, backup, or disposal. A data custodian acts as an agent of the data owner, who is the person or entity that has the authority and accountability for the data. A data custodian should ensure that data is protected according to the classification, which is the process of assigning a level of sensitivity and criticality to the data, based on the impact of its loss, disclosure, or modification. Data classification helps to determine the appropriate security controls and risk responses for the data, and to comply with the relevant laws, regulations, or contractual obligations. References = Risk and Information Systems Control Study Manual, 7th Edition, Chapter 3, Section 3.2.1, page 1271

Penetration test results are the most helpful resource to a risk practitioner when updating the likelihood rating in the risk register. Penetration testing is a method of simulating real-world attacks on an IT system or network to identify and exploit vulnerabilities and measure the potential impact. Penetration test results provide empirical evidence of the existence and severity of vulnerabilities, as well as the ease and probability of exploitation. These results can help the risk practitioner to update the likelihood rating of the risks associated with the vulnerabilities, and to prioritize the risk response actions. Risk control assessment, audit reports with risk ratings, and business impact analysis (BIA) are also useful resources for risk management, but they are not as directly related to the likelihood rating as penetration test results. References = Risk and Information Systems Control Study Manual, Chapter 2, Section 2.3.3, page 2-28.

An IT risk register is a document that records and tracks the identified IT risks, their likelihood, impact, and mitigation strategies. It is a living document that needs to be updated regularly to reflect the current risk profile of the organization. One of the situations that would require updates to the IT risk register is the discovery of an ineffectively designed key IT control, as this would increase the likelihood or impact of the related IT risk. Management review of key risk indicators (KRIs), changes to the team responsible for maintaining the register, and completion of the latest internal audit are not reasons to update the IT risk register, as they do not affect the identified IT risks or their mitigation strategies. References = [CRISC Review Manual (Digital Version)], page 97; CRISC: Certified in Risk & Information Systems Control Sample Questions, question 198.

Risk tolerance and appetite are the expressions of the amount and type of risk that an organization is willing to accept in pursuit of its objectives. Risk tolerance is the acceptable level of variation that the organization is willing to allow for the outcome of its risk decisions. Risk appetite is the broad-based amount of risk that the organization is willing to accept in its activities. The primary objective of establishing an organization's risk tolerance and appetite is to assist management in decision making, as they provide guidance and boundaries for the risk management activities and decisions. By establishing the risk tolerance and appetite, the organization can align its risk exposure with its strategic goals, optimize its risk-return trade-off, and enhance its risk culture and performance. References = CRISC Review Manual, 7th Edition, page 61.

A key risk indicator (KRI) is a metric that measures the changes in the level of risk exposure, such as by monitoring the risk drivers, triggers, or events. A KRI indicates a reduction in the percentage of appropriately patched servers means that the enterprise is not applying the latest security updates or fixes to its servers, which could expose them to vulnerabilities or threats. The best course of action for the risk practitioner when a KRI indicates a reduction in the percentage of appropriately patched servers is to determine changes in the risk level. The risk level is the measure of the impact and likelihood of the risk, and it should be consistent and comparable across the enterprise and over time. By determining changes in the risklevel, the risk practitioner can assess the current or emerging risks, and decide on the appropriate risk response strategy and actions. The other options are not the best course of action, as they involve different aspects or outcomes of the risk management process:
Outsource the vulnerability management process means that the enterprise transfers the responsibility or burden of identifying, analyzing, prioritizing, and remediating the vulnerabilities in the IT systems and applications to a third party, such as a vendor or a contractor. This may not be a feasible or effective way to address the risk of unpatched servers, as it may not reduce the exposure or impact of the risk, or may introduce new risks, such as contractual disputes, quality issues, or intellectual property rights.
Review the patch management process means that the enterprise evaluates the existing procedures and practices for applying the security updates or fixes to the servers, and identifies the gaps or weaknesses that need to be addressed. This may be a useful step in the risk management process, but it is not the best course of action, as it may not provide immediate or sufficient information or action to address the risk of unpatched servers, or may not account for the uncertainties or complexities of the risk.
Add agenda item to the next risk committee meeting means that the enterprise communicates the risk of unpatched servers to the senior executives who oversee the enterprise-wide risk management program, and provide guidance and direction to the risk owners and practitioners. This may be a helpful step in the risk management process, but it is not the best course of action, as it may not provide timely or adequate information or action to address the risk of unpatched servers, or may not reflect the urgency or priority of the risk. References = Risk and Information Systems Control Study Manual, 7th Edition, Chapter 4, Section
4.3.2.1, pp. 171-172.