A preventive measure is a measure that aims to avoid or reduce the likelihood or impact of an unwanted incident. Putting sensitive information in a safe is an example of such a measure, as it protects the information from unauthorized access, theft, damage or loss. Installing a logging system, shutting down internet traffic or restoring data from backups are not preventive measures, but rather detective, corrective or recovery measures. They do not prevent incidents from happening, but rather help to identify, stop or recover from them. ISO/IEC 27001:2022 defines preventive action as "action to eliminate the cause of a potential nonconformity or other undesirable potential situation" (see clause 3.38). Reference: [CQI & IRCA Certified ISO/IEC 27001:2022 Lead Auditor Training Course], ISO/IEC 27001:2022 Information technology - Security techniques - Information security management systems - Requirements, What is Preventive Measure?

Explanation
According to the PECB Candidate Handbook for ISO/IEC 27001 Lead Auditor, audit methods can be classified into two categories: with or without interaction with individuals representing the auditee (page 12).
Audit methods with interaction include reviewing checklists with auditee and conducting interviews, as they involve direct communication and feedback from the auditee. Audit methods without interaction include sampling (e.g. products), observing work performed via live video streaming, checking legal compliance with local authorities, and analysing documents provided in advance of the audit, as they do not require any dialogue or exchange with the auditee. References: PECB Candidate Handbook for ISO/IEC 27001 Lead Auditor, page 12.

The audit team stated that the risk of a significant defect occurring in Data Grid Inc.'s ISMS was low. This refers to "Control Risk," which is the risk that a misstatement could occur in any relevant assertion related to an ISMS and that the risk could not be prevented or detected on a timely basis by the organization's internal control systems.
References: ISO 19011:2018, Guidelines for auditing management systems

The two phrases that would apply to 'check' in the Plan-Do-Check-Act cycle for a business process are:
C. Verifying training
F. Auditing processes
C. This phrase applies to 'check' in the PDCA cycle because it involves measuring and evaluating the effectiveness of the training activities that were implemented in the 'do' phase. Training is an important aspect of information security awareness, education, and competence, which are required by clause 7.2 of ISO 27001:20221. Verifying training can help the organisation to assess whether the staff have acquired the necessary knowledge, skills, and behaviour to perform their roles and responsibilities in relation to information security. Verifying training can also help the organisation to identify any gaps or weaknesses in the training program and to plan for improvement actions.
F. This phrase applies to 'check' in the PDCA cycle because it involves examining and reviewing the performance and conformity of the processes that were implemented in the 'do' phase. Auditing is a systematic, independent, and documented process for obtaining objective evidence and evaluating it to determine the extent to which the audit criteria are fulfilled2. Auditing processes can help the organisation to verify whether the information security objectives and requirements are met, whether the information security controls are effective and efficient, and whether the information security risks are adequately managed. Auditing processes can also help the organisation to identify any nonconformities or opportunities for improvement and to plan for corrective or preventive actions.
References:
1: ISO/IEC 27001:2022 - Information technology - Security techniques - Information security management systems - Requirements, clause 7.2 2: ISO 19011:2018 - Guidelines for auditing management systems, clause 3.2

A. I will check the other data centres are treated as external providers, even though they are part of the same telecommunication group. This is appropriate because clause 8.1.4 of ISO 27001:2022 requires the organisation to ensure that externally provided processes, products or services that are relevant to the information security management system are controlled. Externally provided processes, products or services are those that are provided by any external party, regardless of the degree of its relationship with the organisation. Therefore, the other data centres within the same telecommunication group should be treated as external providers and subject to the same controls as any other external provider12
B. I will ensure external providers have a documented process in place to notify the organisation of any risks arising from the use of its products or services. This is appropriate because clause 8.1.4 of ISO
27001:2022 requires the organisation to implement appropriate contractual requirements related to information security with external providers. One of the contractual requirements could be the obligation of the external provider to notify the organisation of any risks arising from the use of its products or services, such as security incidents, vulnerabilities, or changes that could affect the information security of the organisation. The external provider should have a documented process in place to ensure that such notification is timely, accurate, and complete12
E. I will ensure the organisation is regularly monitoring, reviewing and evaluating external provider performance. This is appropriate because clause 8.1.4 of ISO 27001:2022 requires the organisation to monitor, review and evaluate the performance and effectiveness of the externally provided processes, products or services. The organisation should have a process in place to measure and verify the conformity and suitability of the external provider's deliverables and activities, and to provide feedback and improvement actions as necessary. The organisation should also maintain records of the monitoring, review and evaluation results12
F. I will ensure the organisation has determined the need to communicate with external providers regarding the ISMS. This is appropriate because clause 7.4.2 of ISO 27001:2022 requires the organisation to determine the need for internal and external communications relevant to the information security management system, including the communication with external providers. The organisation should define the purpose, content, frequency, methods, and responsibilities for such communication, and ensure that it is consistent with the information security policy and objectives. The organisation should also retain documented information of the communication as evidence of its implementation12 The following activities are not appropriate for the assessment of external providers according to ISO
27001:2022:
C. I will ensure that the organisation has a reserve external provider for each process it has identified as critical to preservation of the confidentiality, integrity and accessibility of its information. This is not appropriate because ISO 27001:2022 does not require the organisation to have a reserve external provider for each critical process. The organisation may choose to have a contingency plan or a backup solution in case of failure or disruption of the external provider, but this is not a mandatory requirement. The organisation should assess the risks and opportunities associated with the external provider and determine the appropriate treatment options, which may or may not include having a reserve external provider12
D. I will limit my audit activity to externally provided processes as there is no need to audit externally provided products or services. This is not appropriate because clause 8.1.4 of ISO 27001:2022 requires the organisation to control the externally provided processes, products or services that are relevant to the information security management system. Externally provided products or services may include software, hardware, data, or cloud services that could affect the information security of the organisation. Therefore, the audit activity should cover both externally provided processes and products or services, as applicable12
G. I will ensure that top management have assigned roles and responsibilities for those providing external ISMS processes as well as internal ISMS processes. This is not appropriate because clause 5.3 of ISO 27001:2022 requires the top management to assign the roles and responsibilities for the information security management system within the organisation, not for the external providers. The external providers are responsible for assigning their own roles and responsibilities for the processes, products or services they provide to the organisation. The organisation should ensure that the external providers have adequate competence and awareness for their roles and responsibilities, and that they are contractually bound to comply with the information security requirements of the organisation12
H. I will ensure that the organisation ranks its external providers and allocates the majority of its work to those providers who are rated the highest. This is not appropriate because ISO 27001:2022 does not require the organisation to rank its external providers or to allocate its work based on such ranking. The organisation may choose to evaluate and compare the performance and effectiveness of its external providers, but this is not a mandatory requirement. The organisation should select and use its external providers based on the information security criteria and objectives that are relevant to the organisation12 References:
1: ISO/IEC 27001:2022 Lead Auditor (Information Security Management Systems) Course by CQI and IRCA Certified Training 1 2: ISO/IEC 27001 Lead Auditor Training Course by PECB 2