The auditor's best action when IT management provides suitable evidence for a control that had been concluded as ineffective is to re-perform the audit before changing the conclusion. This means that the auditor should verify the validity, completeness, and timeliness of the evidence provided by IT management and test the effectiveness of the new control in meeting the audit objectives. The auditor should not change the conclusion based on evidence provided by IT management without re-performing the audit, as this could compromise the auditor's independence and objectivity. The auditor should also not explain to IT management that the new control will be evaluated during follow-up or add comments about the action taken by IT management in the report, as these actions do not address the original audit finding. References: CISA Review Manual, 27th Edition, page 439

The best way to mitigate risk to an organization's network associated with devices permitted under a BYOD policy is to implement a network access control system, as this will allow the organization to monitor, authenticate, and authorize the devices that connect to the network, and to enforce security policies and compliance requirements12. A network access control system can help to prevent unauthorized or compromised devices from accessing sensitive data or resources, and to detect and isolate any potential threats or vulnerabilities34.
References
1: Network Access Control (NAC) - ISACA 2: Network Access Control (NAC) - Cisco 3: BYOD Security Risks: 6 Ways to Protect Your Organization - ReliaQuest5 4: How to Mitigate BYOD Risks and Challenges - CIOReview6

The greatest concern for an IS auditor reviewing an organization's disaster recovery plan (DRP) is that the DRP has not been updated since an IT infrastructure upgrade. This could render the DRP obsolete or ineffective, as it may not reflect the current configuration, dependencies or recovery requirements of the IT systems. The IS auditor should ensure that the DRP is reviewed and updated regularly to align with any changes in the IT environment. The DRP has not been formally approved by senior management is a concern for an IS auditor reviewing an organization's DRP, but it is not as critical as ensuring that the DRP is up to date and valid. The DRP has not been distributed to end users or the DRP contains recovery procedures for critical servers only are issues that relate to the communication or scope of the DRP, but not to its validity or effectiveness. References: ISACA, CISA Review Manual, 27th Edition, 2018, page 389