The best audit procedure to determine whether a firewall is configured in compliance with the organization's security policy is reviewing the parameter settings. Parameter settings are values or options that define how a firewall operates and functions, such as rules, filters, ports, protocols, etc. By reviewing the parameter settings of a firewall, an IS auditor can verify whether they match with the organization's security policy, which is a document that outlines the security objectives, requirements, and guidelines for an organization's information systems and resources. Reviewing the system log is a possible audit procedure to determine whether a firewall is configured in compliance with the organization's security policy, but it is not the best one, as a system log records events or activities that occur on a firewall, such as connections, requests, responses, errors, alerts, etc., and may not indicate whether they comply with the organization's security policy. Interviewing the firewall administrator is a possible audit procedure to determine whether a firewall is configured in compliance with the organization's security policy, but it is not the best one, as a firewall administrator may not provide accurate or reliable information about the firewall configuration, and may have conflicts of interest or ulterior motives. Reviewing the actual procedures is a possible audit procedure to determine whether a firewall is configured in compliance with the organization's security policy, but it is not the best one, as actual procedures describe how a firewall is configured and maintained, such as installation, testing, updating, etc., and may not reflect whether they comply with the organization's security policy.

The best recommendation to prevent unauthorized access to cloud-based applications and data is to implement multi-factor authentication (MFA). MFA is a method of verifying the identity of a user by requiring two or more pieces of evidence, such as a password, a code sent to a phone, or a biometric factor. MFA adds an extra layer of security to prevent unauthorized access, even if the user's password is compromised or stolen. MFA can also help comply with data privacy and security regulations, such as the General Data Protection Regulation (GDPR) and the Health Insurance Portability and Accountability Act (HIPAA).
The other options are not as effective as MFA in preventing unauthorized access. An intrusion detection system (IDS) is a tool that monitors network traffic and alerts administrators of suspicious or malicious activity, but it does not prevent access by itself. Updating security policies and procedures is a good practice, but it does not ensure that users follow them or that they are enforced. Utilizing strong anti-malware controls on all computing devices can help protect against malware infections, but it does not prevent users from accessing cloud-based applications and data from any Internet-connected web browser.
References:
ISACA, CISA Review Manual, 27th Edition, 2019, p. 2471
ISACA, CISAReview Questions, Answers & ExplanationsDatabase - 12 Month Subscription2 What Is Cloud Security? | Google Cloud3
5 Cloud Application Security Best Practices | Snyk4

The chain of custody has not been documented is a finding that should be of greatest concern for an IS auditor reviewing a forensic analysis process of an organization that has suffered a cyber attack. The chain of custody is a record of who handled, accessed, or modified the evidence during a forensic investigation.
Documenting the chain of custody is essential to preserve the integrity, authenticity, and admissibility of the evidence in a court of law. The other options are less concerning findings that may not affect the validity or reliability of the forensic analysis process. References:
* CISAReview Manual (Digital Version), Chapter 7, Section 7.51
* CISA Review Questions, Answers &Explanations Database, Question ID 220

The most important thing for an IS auditor to look for in a project feasibility study is an assessment of whether the expected benefits can be achieved. A project feasibility study is a preliminary analysis that evaluates the viability and suitability of a proposed project based on various criteria, such as technical, economic, legal, operational, and social factors. The expected benefits are the positive outcomes and value that the project aims to deliver to the organization and its stakeholders. The IS auditor should verify whether the project feasibility study has clearly defined and quantified the expected benefits, and whether it has assessed the likelihood and feasibility of achieving them within the project scope, budget, schedule, and quality parameters. The other options are also important for an IS auditor to look for in a project feasibility study, but not as important as an assessment of whether the expected benefits can be achieved, because they either focus on specific aspects of the project rather than the overall value proposition, or they assume that the project will be implemented rather than evaluating its viability. References: CISA Review Manual (Digital Version)1, Chapter 4, Section 4.2.1

The greatest concern with this situation is that a business-critical application does not currently have any level of fault tolerance and thus has a single point of failure. A single point of failure is a component or element of a system that, if it fails, will cause the entire system to stop functioning. Fault tolerance is the ability of a system to continue operating without interruption or degradation in the event of a failure of one or more of its components or elements. Fault tolerance can be achieved by using techniques such as redundancy, replication, backup, or failover. A business-critical application should have a high level of fault tolerance to ensure its availability, reliability, and continuity. References:
* CISA Review Manual (Digital Version), Chapter 5, Section 5.51
* CISA Online Review Course, Domain 3, Module 3, Lesson 22