An external audit is an appropriate tool and technique to support a customer's verification of the cloud service provider's claims regarding its responsibilities according to the shared responsibility model. An external audit is an independent and objective examination of the cloud service provider's policies, procedures, controls, and performance by a qualified third-party auditor. An external audit can provide assurance that the cloud service provider is fulfilling its obligations and meeting the customer's expectations in terms of security, compliance, availability, reliability, and quality. An external audit can also identify any gaps or weaknesses in the cloud service provider's security posture and suggest recommendations for improvement.
An external audit can be based on various standards, frameworks, and regulations that are relevant to the cloud service provider's industry and domain. For example, some common external audits for cloud service providers are:
* ISO/IEC 27001: This is an international standard that specifies the requirements for establishing, implementing, maintaining, and continually improving an information security management system (ISMS). An ISMS is a systematic approach to managing sensitive information so that it remains secure. An ISO/IEC 27001 certification demonstrates that the cloud service provider has implemented a comprehensive and effective ISMS that covers all aspects of information security, including risk assessment, policy development, asset management, access control, incident management, business continuity, and compliance.1
* SOC 2: This is an attestation report that evaluates the cloud service provider's security controls based on the American Institute of Certified Public Accountants (AICPA) Trust Services Criteria. The Trust Services Criteria are a set of principles and criteria for evaluating the design and operating effectiveness of controls that affect the security, availability, processing integrity, confidentiality, and privacy of a system. A SOC 2 report provides assurance that the cloud service provider has implemented adequate controls to protect the customer's data and systems.2
* CSA STAR: This is a program for flexible, incremental, and multi-layered cloud provider certification and/or attestation according to the Cloud Security Alliance's industry leading security guidance and control framework. The CSA STAR program consists of three levels of assurance: Level 1: Self- Assessment, Level 2: Third-Party Audit, and Level 3: Continuous Auditing. The CSA STAR program aims to provide transparency, assurance, and trust in the cloud ecosystem by enabling customers to assess and compare the security and compliance posture of cloud service providers.3 The other options listed are not suitable for supporting a customer's verification of the cloud service provider' s claims regarding its responsibilities according to the shared responsibility model. An internal audit is an audit conducted by the cloud service provider itself or by an internal auditor hired by the cloud service provider. An internal audit may not be as independent or objective as an external audit, and it may not provide sufficient evidence or credibility to the customer. A contractual agreement is a legal document that defines the roles, responsibilities, expectations, and obligations of both the cloud service provider and the customer. A contractual agreement may specify the terms and conditions for service delivery, performance, availability, security, compliance, data protection, incident response, dispute resolution, liability, and termination.
However, a contractual agreement alone does not verify or validate whether the cloud service provider is actually fulfilling its claims or meeting its contractual obligations. A security assessment is a process of identifying, analyzing, and evaluating the security risks and vulnerabilities of a system or an organization. A security assessment may involve various methods such as vulnerability scanning, penetration testing, threat modeling, or risk analysis. A security assessment may provide useful information about the current state of security of a system or an organization, but it may not cover all aspects of the shared responsibility model or provide assurance that the cloud service provider is complying with its responsibilities on an ongoing basis.

According to the ISACA Cloud Auditing Knowledge Certificate Study Guide, the final decision to include a material finding in a cloud audit report should be made by the cloud auditor1. A material finding is a significant error or risk in the cloud service that could affect the achievement of the audit objectives or the cloud customer's business outcomes. The cloud auditor is responsible for identifying, evaluating, and reporting the material findings based on the audit criteria, methodology, and evidence. The cloud auditor should also communicate the material findings to the auditee and other relevant stakeholders, and obtain their feedback and responses.
The other options are not correct. Option A is incorrect, as the auditee's senior management is not in charge of the audit report, but rather the subject of the audit. The auditee's senior management should provide their perspective and action plans for the material findings, but they cannot decide whether to include or exclude them from the report. Option B is incorrect, as the organization's CEO is not involved in the audit process, but rather the ultimate recipient of the audit report. The organization's CEO should review and act upon the audit report, but they cannot influence the content of the report. Option D is incorrect, as the organization's CISO is not an independent party, but rather a stakeholder of the audit. The organization's CISO should support and collaborate with the cloud auditor, but they cannot make the final decision on the material findings. Reference:
ISACA Cloud Auditing Knowledge Certificate Study Guide, page 19-20.

A security categorization of the information systems should be performed first to properly implement the NIST SP 800-53 r4 control framework in an organization. Security categorization is the process of determining the potential impact on organizational operations, organizational assets, individuals, other organizations, and the Nation resulting from a loss of confidentiality, integrity, or availability of an information system and the information processed, stored, or transmitted by that system. Security categorization is based on the application of FIPS Publication 199, Standards for Security Categorization of Federal Information and Information Systems, which defines three levels of impact: low, moderate, and high. Security categorization is the first step in the Risk Management Framework (RMF) described in NIST SP 800-37, Revision 2, Risk Management Framework for Information Systems and Organizations: A System Life Cycle Approach for Security and Privacy. Security categorization helps to identify the security requirements for the information system and to select an initial set of baseline security controls from NIST SP 800-53 r4, Security and Privacy Controls for Federal Information Systems and Organizations. The baseline security controls can then be tailored and supplemented as needed to address specific organizational needs, risk factors, and compliance obligations12.
Reference:
SP 800-53 Rev. 4, Security & Privacy Controls for Federal Info Sys ...
SP 800-37 Rev. 2, Risk Management Framework for Information ...

An example of financial business impact is a distributed denial of service (DDoS) attack that renders the customer's cloud inaccessible for 24 hours, resulting in millions in lost sales. Financial business impact refers to the monetary losses or gains that an organization may experience as a result of a cloud security incident. Financial business impact can be measured by factors such as revenue, profit, cost, cash flow, market share, and stock price .
Option A is an example of financial business impact because it shows how a DDoS attack, which is a type of cyberattack that overwhelms a system or network with malicious traffic and prevents legitimate users from accessing it, can cause direct and significant financial losses for the customer's organization due to the interruption of its cloud services and the inability to generate sales. Option A also implies that the customer's organization depends on the availability of its cloud services for its core business operations.
The other options are not examples of financial business impact. Option B is an example of operational business impact, which refers to the disruption or degradation of the organization's processes, functions, or activities as a result of a cloud security incident. Operational business impact can be measured by factors such as productivity, efficiency, quality, performance, and customer satisfaction . Option B shows how a hacker using a stolen administrator identity, which is a type of identity theft or impersonation attack that exploits the credentials or privileges of a legitimate user to access or manipulate a system or network, can cause operational business impact for the customer's organization by bringing down its SaaS sales and marketing systems, which are essential for its business functions.
Option C is an example of reputational business impact, which refers to the damage or enhancement of the organization's image, brand, or reputation as a result of a cloud security incident. Reputational business impact can be measured by factors such as trust, loyalty, satisfaction, awareness, and perception of the organization's stakeholders, such as customers, partners, investors, regulators, and media . Option C shows how a breach reported in a timely manner to the CEO, which is a good practice for ensuring transparency and accountability in the event of a cloud security incident, can still cause reputational business impact for the customer's organization due to the public blame game between the CFO and CISO, which reflects poorly on the organization's leadership and culture and leads to the board replacing all three. Reference := Business Impact Analysis - Ready.gov Business Impact Analysis - Cloud Security Alliance What Is A Distributed Denial-of-Service (DDoS) Attack? | Cloudflare What is Identity Theft? - Cloud Security Alliance Incident Response - Cloud Security Alliance

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