The auditor's next course of action should be to evaluate the appropriateness of the remedial action taken by the auditee. The auditor should assess whether the alternative approach taken by the auditee is effective, efficient, and aligned with the audit objectives and recommendations. The auditor should also consider the impact of the change on the audit scope, criteria, and risk assessment. Conducting a risk analysis incorporating the change, reporting results of the follow-up to the audit committee, and informing senior management of the change in approach are possible subsequent actions that the auditor may take after evaluating the appropriateness of the remedial action taken. References: CISA Review Manual (Digital Version): Chapter 1 - Information Systems Auditing Process

Digital watermarks are hidden marks or codes that can be embedded into digital files, such as images, videos, audio, or documents. They can be used to identify the source, owner, or authorized user of the data, as well as to track any unauthorized copying or distribution of the data. Digital watermarks can help prevent data leakage by deterring potential leakers from sharing sensitive data or by providing evidence of data leakage if it occurs.
The other options are not as effective as digital watermarks in preventing data leakage. Ensuring that paper documents are disposed securely can reduce the risk of physical data leakage, but it does not address the digital data leakage that is more prevalent in today's environment. Implementing an intrusion detection system (IDS) can help detect and respond to cyberattacks that may cause data leakage, but it does not prevent data leakage from insiders or authorized users who have legitimate access to the data. Verifying that application logs capture any changes made can help audit and investigate data leakage incidents, but it does not prevent them from happening in the first place.
References:
* What is Data Leakage?
* What is Digital Watermarking?

Access controls for source libraries are the features of a library control software package that would protect against unauthorized updating of source code. Access controls are the mechanisms that regulate who can access, modify, or delete the source code stored in the source libraries. Source libraries are the repositories that contain the source code files and their versions. By implementing access controls for source libraries, the library control software package can prevent unauthorized or malicious users from tampering with the source code and compromising its integrity, security, or functionality1.
The other options are not as effective as access controls for source libraries in protecting against unauthorized updating of source code. Option A, required approvals at each life cycle step, is a good practice but may not be sufficient to prevent unauthorized updates if the approval process is bypassed or compromised. Option B, date and time stamping of source and object code, is a useful feature but may not prevent unauthorized updates if the date and time stamps are altered or ignored. Option D, release-to-release comparison of source code, is a helpful feature but may not prevent unauthorized updates if the comparison results are not reviewed or acted upon.
References:
* ISACA, CISA Review Manual, 27th Edition, 2019
* ISACA, CISA Review Questions, Answers & Explanations Database - 12 Month Subscription
* How to protect your source code from attackers2
* How to Stop Unauthorized Use of Open Source Code

Comprehensive and Detailed Step-by-Step Explanation:
Wireless security relies onstrong encryptionto prevent unauthorized access and data interception.
* Option A (Correct):WPA3is thelatest and most secureWi-Fi encryption standard, offeringstronger protectionagainst brute-force attacks and improvingkey management.
* Option B (Incorrect):DES is outdatedand vulnerable tomodern attacks, making it unsuitable for wireless security.
* Option C (Incorrect):WEP is highly insecuredue toweak encryptionand can be cracked inminutes using basic tools.
* Option D (Incorrect):SSL secures web traffic, notwireless networks.
Reference:ISACA CISA Review Manual -Domain 5: Protection of Information Assets- Coverswireless security, encryption, and network security best practices.

Developing a risk-based plan considering each entity's business processes would best help to ensure that IS audit still covers key risk areas within the IT environment as part of its annual plan. A risk-based plan is a plan that prioritizes the audit activities based on the level of risk associated with each area or process. A risk-based plan can help to allocate the audit resources more efficiently and effectively, and provide more assurance and value to the stakeholders1.
By considering each entity's business processes, the IS audit can identify and assess the specific risks and controls that affect the IT environment of each entity, and tailor the audit objectives, scope, and procedures accordingly. This can help to address the unique needs and expectations of each entity, and ensure that the IS audit covers the key risk areas that are relevant and significant to each entity's operations, performance, and compliance2.
The other options are not as effective as developing a risk-based plan considering each entity's business processes in ensuring that IS audit still covers key risk areas within the IT environment as part of its annual plan. Option A, increasing the frequency of risk-based IS audits for each business entity, is not a feasible or efficient solution, as it may increase the audit costs and workload, and create duplication or overlap of audit efforts. Option C, conducting an audit of newly introduced IT policies and procedures, is a limited and narrow approach, as it may not cover all the aspects or dimensions of the IT environment that may have changed or been affected by the split. Option D, revising IS audit plans to focus on IT changes introduced after the split, is a reactive and short-term approach, as it may not reflect the current or future state of the IT environment or the business objectives of each entity.
References:
* ISACA, CISA Review Manual, 27th Edition, 2019
* ISACA, CISA Review Questions, Answers & Explanations Database - 12 Month Subscription
* Risk-Based Audit Planning: A Guide for Internal Audit1
* Risk-Based Audit Approach: Definition & Example