End-user computing (EUC) is a system in which users are able to create working applications besides the divided development process of design, build, test and release that is typically followed by software engineers1. Examples of EUC tools include spreadsheets, databases, low-code/no-code platforms, and generative AI applications2. EUC tools can provide flexibility, efficiency, and innovation for the users, but they also pose significant risks if not properly managed and controlled3.
The greatest risk when relying on reports generated by EUC is that the data may be inaccurate. Data accuracy refers to the extent to which the data in the reports reflect the true values of the underlying information4.
Inaccurate data can lead to erroneous decisions, misleading analysis, unreliable reporting, and compliance violations. Some of the factors that can cause data inaccuracy in EUC reports are:
Lack of rigorous testing: EUC tools may not undergo the same level of testing and validation as IT-developed applications, which can result in errors, bugs, or inconsistencies in the data processing and output3.
Lack of version and change control: EUC tools may not have a clear record of the changes made to them over time, which can create confusion, duplication, or loss of data. Users may also modify or overwrite the data without proper authorization or documentation3.
Lack of documentation and reliance on end-user who developed it: EUC tools may not have sufficient documentation to explain their purpose, functionality, assumptions, limitations, and dependencies. Users may also rely on the knowledge and expertise of the original developer, who may not be available or may not have followed best practices3.
Lack of maintenance processes: EUC tools may not have regular updates, backups, or reviews to ensure their functionality and security. Users may also neglect to delete or archive obsolete or redundant data3.
Lack of security: EUC tools may not have adequate access controls, encryption, or authentication mechanisms to protect the data from unauthorized access, modification, or disclosure. Users may also store or share the data in insecure locations or devices3.
Lack of audit trail: EUC tools may not have a traceable history of the data sources, inputs, outputs, calculations, and transformations. Users may also manipulate or falsify the data without detection or accountability3.
Overreliance on manual controls: EUC tools may depend on human intervention to input, verify, or correct the data, which can introduce errors, delays, or biases. Users may also lack the skills or training to use the EUC tools effectively and efficiently3.
The other options are not as great as data inaccuracy when relying on EUC reports. Reports may not work efficiently, reports may not be timely, and historical data may not be available are all potential risks associated with EUC tools, but they are less severe and less frequent than data inaccuracy. Moreover, these risks can be mitigated by improving the performance, scheduling, and storage of the EUC tools. However, data inaccuracy can have a pervasive and lasting impact on the quality and credibility of the reports and the decisions based on them. Therefore, option A is the correct answer.
References:
What is Data Accuracy?
What Is End User Computing (EUC) Risk?
End-user computing
End-User Computing (EUC) Risks: A Comprehensive Guide

The first course of action when a data breach has occurred due to malware is to quarantine the impacted systems. This means isolating the infected systems from the rest of the network and preventing any further communication or data transfer with them. This can help contain the spread of the malware, limit the damage and exposure of sensitive data, and facilitate the investigation and remediation of the incident. Quarantining the impacted systems can also help preserve the evidence and logs that may be needed for forensic analysis or legal action.
References:
* [1] provides a guide on how to respond to a data breach caused by malware and recommends quarantining the impacted systems as the first step.
* [2] explains what is malware and how it can cause data breaches, and suggests quarantining the infected devices as a best practice.
* [3] describes the steps involved in quarantining a system infected by malware and the benefits of doing so.

The IS auditor's next course of action after finding that firewalls are outdated and not supported by vendors should be to determine the risk of not replacing the firewall. Outdated firewalls may have known vulnerabilities that can be exploited by attackers to bypass security controls and access the network. They may also lack compatibility with newer technologies or standards that are required for optimal network performance and protection. Not replacing the firewall could expose the organization to various threats, such as data breaches, denial-of-service attacks, malware infections, or regulatory non-compliance. The IS auditor should assess the likelihood and impact of these threats and quantify the risk level for management to make informed decisions.

A system electronic log is the most useful source of information for an IS auditor to review all access attempts to a video-monitored and proximity card-controlled communications room. A system electronic log can provide accurate and detailed records of the date, time, card number, and status (success or failure) of each access attempt. A system electronic log can also be easily searched, filtered, and analyzed by the auditor to identify any unauthorized or suspicious access attempts.
A manual sign-in and sign-out log is not as reliable or useful as a system electronic log, because it depends on the honesty and compliance of the users. A manual log can be easily manipulated, forged, or omitted by the users or intruders. A manual log also does not capture the status of each access attempt, and it can be difficult to verify the identity of the users based on their signatures.
An alarm system with CCTV is not as useful as a system electronic log, because it only captures the events that trigger the alarm, such as unauthorized or forced entry. An alarm system with CCTV does not provide a complete record of all access attempts, and it can be affected by factors such as camera angle, lighting, and resolution. An alarm system with CCTV also requires more time and effort to review the video footage by the auditor.
A security incident log is not as useful as a system electronic log, because it only records the incidents that are reported by the users or detected by the security staff. A security incident log does not provide a comprehensive record of all access attempts, and it can be incomplete or inaccurate depending on the reporting and detection mechanisms. A security incident log also does not capture the details of each access attempt, such as the card number and status.
References:
* ISACA CISA Review Manual 27th Edition (2019), page 247
* ISACA CISA Certified Information Systems Auditor Exam ... - PUPUWEB