The first step that an IS auditor should take when finding that a business impact analysis (BIA) has not been performed is to evaluate the impact on current disaster recovery capability. A BIA is a process that identifies and analyzes the potential effects of disruptions to critical business functions and processes. A BIA helps determine the recovery priorities, objectives, and strategies for the organization. Without a BIA, the disaster recovery plan may not be aligned with the business needs and expectations, and may not provide adequate protection and recovery for the most critical assets and activities. Therefore, an IS auditor should assess how the lack of a BIA affects the current disaster recovery capability and identify any gaps or risks that need to be addressed.
Performing a BIA, issuing an intermediate report to management, and conducting additional compliance testing are not the first steps that an IS auditor should take when finding that a BIA has not been performed.
These steps may be done later in the audit process, after evaluating the impact on current disaster recovery capability. Performing a BIA is not the responsibility of the IS auditor, but of the business owners and managers. Issuing an intermediate report to management may be premature without sufficient evidence and analysis. Conducting additional compliance testing may not be relevant or necessary without a clear understanding of the disaster recovery requirements and objectives.

The impact if corrective actions are not taken is the most important factor to consider when scheduling follow- up audits. An IS auditor should prioritize the follow-up audits based on the risk and potential consequences of not addressing the audit findings and recommendations. The other options are less important factors that may affect the timing and scope of the follow-up audits, but not their necessity or urgency. References:
* CISA Review Manual(Digital Version), Chapter 2, Section 2.5.31
* CISA Review Questions, Answers & Explanations Database, Question ID 207

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 controlsoftware 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

Compared to developing a system in-house, acquiring a software package means that the need for testing by end users is unchanged. This is because end users are still the ultimate customers and beneficiaries of the system, and they need to ensure that the software package meets their requirements, expectations, and satisfaction. End user testing, also known as user acceptance testing (UAT) or beta testing, is the final stage of testing performed by the user or client to determine whether the software can be accepted or not1. End user testing is important for both in-house developed and acquired software packages, as it helps to verify the functionality, usability, performance, and reliability of the system2. End user testing also helps to identify and resolve any defects, errors, or issues that may not have been detected by the developers or vendors3.
Therefore, option B is the correct answer.
Option A is not correct because end user testing is not eliminated by acquiring a software package. Even though the software package may have been tested by the vendor or supplier, it may still have bugs, compatibility issues, or configuration problems that need to be fixed before deployment4. Option C is not correct because end user testing is not increased by acquiring a software package. The scope and extent of end user testing depend on various factors, such as the complexity, criticality, and customization of the system, and not on whether it is developed in-house or acquired. Option D is not correct because end user testing is not reduced by acquiring a software package. The software package may still require modifications or integrations to suit the specific needs and environment of the organization, and these changes need to be tested by the end users.
References:
Chapter 4 Methods of Software Acquisition5
What is User Acceptance Testing (UAT): A Complete Guide1
What Is End-to-End Testing? (With How-To and Example)3
How to Evaluate New Software in 5 Steps4
User Acceptance Testing (UAT) in ERP Projects
User Acceptance Testing for Packaged Software

Involving the application owner early in the audit planning process is the best way to contribute to the quality of an audit of a business-critical application. The application owner has a deep understanding of the application and its business context, which can provide valuable insights for the audit. Early involvement can also help ensure that the audit is aligned with the business objectives and risks, and that any potential issues are identified and addressed promptly12.
References:
Business Critical Applications: An In-Depth Look
Framework for Audit Quality - IFAC