When an IS audit reveals that a firewall was unable to recognize a number of attack attempts, the auditor's best recommendation is to place an intrusion detection system (IDS) between the firewall and the Internet, as this would provide an additional layer of security and alert the organization of any malicious traffic that bypasses or penetrates the firewall. Placing an IDS between the firewall and the demilitarized zone (DMZ), the organization's web server, or the organization's network would not be as effective, as it would only monitor the traffic that has already passed through the firewall. References: CISA Review Manual (Digital Version), Chapter 5, Section 5.4.3

The first task that an IS auditor should complete during the preliminary planning phase of a database security review is to determine which databases will be in scope. The scope defines the boundaries and objectives of the audit, as well as the resources, time, and budget required. The IS auditor should identify the databases that are relevant to the audit based on factors such as their criticality, risk, complexity, size, type, location, and ownership. The IS auditor should also consider the regulatory, contractual, and organizational requirements that apply to the databases. By defining the scope clearly and accurately, the IS auditor can ensure that the audit is focused, feasible, and effective. References:
* CISA Review Manual (Digital Version)
* CISA Questions, Answers & Explanations Database

The best way to ensure the quality and integrity of test procedures used in audit analytics is to centralize procedures and implement change control. Centralizing procedures means storing them in a common repository that can be accessed and updated by authorized users. Change control means implementing a process for tracking, reviewing, approving, and documenting any changes made to the procedures. This ensures that the procedures are consistent, accurate, reliable, and secure. References: CISA Review Manual,
27th Edition, page 401

The type of review that is most important to conduct when an IS auditor is informed that a recent internal exploitation of a bug has been discovered in a business application is C. Forensic audit. A forensic audit is a type ofaudit that involves collecting, analyzing, and preserving evidence of fraud, corruption, or other illegal or unethical activities1. A forensic audit can help the IS auditor to identify and document the source, scope, and impact of the exploitation, as well as the perpetrators, motives, and methods involved. A forensic audit can also help the IS auditor to provide recommendations for preventing or mitigating future exploitations, and to support any legal actions or investigations that may arise from the incident2.