The most effective way to ensure the integrity of data transmitted over a network is to use a message digest. A message digest is a cryptographic function that generates a unique and fixed-length value (also known as a hash or checksum) from any input data. The message digest can be used to verify that the data has not been altered or corrupted during transmission by comparing it with the message digest generated at the destination.
Message encryption is a method of protecting the confidentiality of data transmitted over a network by transforming it into an unreadable format using a secret key. Message encryption does not ensure the integrity of data, as it does not prevent or detect unauthorized modifications. Certificate authority (CA) is an entity that issues and manages digital certificates that bind public keys to identities. CA does not ensure the integrity of data, as it does not prevent or detect unauthorized modifications. Steganography is a technique of hiding data within other data, such as images or audio files. Steganography does not ensure the integrity of data, as it does not prevent or detect unauthorized modifications. References:
* CISA Review Manual, 27th Edition, pages 383-3841
* CISA Review Questions, Answers & Explanations Database, Question ID: 258

Machine shredding is the process of using a shredding machine to physically destroy the media and make the data unrecoverable. This is more effective than software formatting, which only erases the data logically and may leave traces that can be recovered by special tools1. Encrypting and destroying keys may prevent unauthorized access to the data, but it does not erase the data from the media. Wiping and rewriting three times is unnecessary and may reduce the lifespan of the media, especially for solid state drives2. Machine shredding is also recommended by various security standards and guidelines for media disposal345.

The auditor's best course of action when senior management disagrees with some of the facts presented in the draft audit report is to gather evidence to analyze senior management's objections. The auditor should not revise the assessment, escalate the issue, or finalize the report without changes until they have evaluated the validity and relevance of senior management's objections and resolved any discrepancies or misunderstandings. The auditor should maintain a professional and objective attitude and seek to present a fair and accurate audit report based on sufficient and appropriate evidence. References:
* CISA Review Manual (Digital Version), page 372
* CISA Questions, Answers & Explanations Database, question ID 3338

Comprehensive and Detailed Step-by-Step Explanation:
AChange Approval Board (CAB)ensures thatall necessary testing and rollback planshave been reviewed before deployment.
* Option A (Correct):ACABensures thatchanges are reviewed, tested, and approved, minimizing risks before an application is deployed. This includes confirming thatrollback plans are in place.
* Option B (Incorrect):Standardized change requestsare important but donot guarantee review and approvalby management and stakeholders.
* Option C (Incorrect):Third-party approvalmay be useful, but internalgovernance and control via a CABis more comprehensive.
* Option D (Incorrect):Secure code reviewshelp identify vulnerabilities, but they donot confirm proper deployment and rollback procedures.
Reference:ISACA CISA Review Manual -Domain 3: Information Systems Acquisition, Development, and Implementation- Coverschange management and deployment best practices.

The first step that the organization should take to ensure that only the corporate network is used for downloading business data is to include a statement in its security policy about Internet use. A security policy is a document that defines the rules, expectations, and overall approach that an organization uses to maintain the confidentiality, integrity, and availability of its data1. A security policy should clearly state the acceptable and unacceptable use of Internet resources, such as personal accounts with ISPs, and the consequences of violating the policy. A security policy also helps to guide the implementation of technical controls, such as proxy servers, firewalls, or monitoring tools, that can enforce the policy and prevent or detect unauthorized Internet access.
The other options are not the first step that the organization should take, but rather subsequent or complementary steps that depend on the security policy. Using a proxy server to filter out Internet sites that should not be accessed is a technical control that can help implement the security policy, but it does not address the root cause of why users are using personal accounts with ISPs. Keeping a manual log of Internet access is a monitoring technique that can help audit the compliance with the security policy, but it does not prevent or deter users from using personal accounts with ISPs. Monitoring remote access activities is another monitoring technique that can help detect unauthorized Internet access, but it does not specify what constitutes unauthorized access or how to respond to it.
References:
* ISACA CISA Review Manual 27th Edition (2019), page 247
* What is a Security Policy? Definition, Elements, and Examples - Varonis1