Explanation
Credential scanning is a technique that can be used to detect and prevent the exposure of access keys and other sensitive information in the source code or any other configuration files during development. Credential scanning tools can scan the code repositories, files, and commits for any hardcoded credentials, such as access keys, passwords, tokens, certificates, and connection strings. They can also alert the developers or security teams of any potential leaks and suggest remediation actions, such as rotating or revoking the compromised keys, removing the credentials from the code, or using secure storage mechanisms like vaults or environment variables. Credential scanning can be integrated into the development pipeline as part of the continuous integration and continuous delivery (CI/CD) process, or performed periodically as a security audit. Credential scanning can help reduce the risk of credential leakage, which can lead to unauthorized access, data breaches, or account compromise. References:
Protecting Source Code in the Cloud with DSPM
Best practices for managing service account keys
Protect your code repository

The CSA Cloud Controls Matrix (CCM) is the best tool to perform cloud security control audits, as it is a cybersecurity control framework for cloud computing that is aligned to the CSA best practices and is considered the de-facto standard for cloud security and privacy1. The CCM provides a set of 197 control objectives that are structured in 17 domains covering all key aspects of cloud technology, such as identity and access management, data security, encryption and key management, business continuity and disaster recovery, audit assurance and compliance, and risk management1. The CCM also maps the controls to various industry-accepted security standards, regulations, and control frameworks, such as ISO
27001/27002/27017/27018, NIST SP 800-53, PCI DSS, GDPR, and others1. The CCM can be used as a tool for the systematic assessment of a cloud implementation, and provides guidance on which security controls should be implemented by which actor within the cloud supply chain1. The CCM also includes the Consensus Assessment Initiative Questionnaire (CAIQ), which provides a set of "yes or no" questions based on the security controls in the CCM that can be used to assess a cloud service provider2.
The other options are not the best tools to perform cloud security control audits, as they are either not specific to cloud computing or not comprehensive enough. GDPR is a regulation that aims to protect the personal data and privacy of individuals in the European Union and the European Economic Area3, but it does not provide a framework for cloud security controls. FIPS 140-2 is a standard that specifies the security requirements for cryptographic modules used by federal agencies in the United States, but it does not cover other aspects of cloud security. ISO 27001 is a standard that specifies the requirements for establishing, implementing, maintaining and continually improving an information security management system within the context of the organization, but it does not provide specific guidance for cloud services. References:
* Cloud Controls Matrix (CCM) - CSA
* Cloud Controls Matrix and CAIQ v4 | CSA - Cloud Security Alliance
* General Data Protection Regulation - Wikipedia
* [FIPS 140-2 - Wikipedia]
* [ISO/IEC 27001:2013]

Explanation
The technical impact of this incident would be categorized as an integrity breach in reference to the Top Threats Analysis methodology. The Top Threats Analysis methodology is a process developed by the Cloud Security Alliance (CSA) to help organizations identify, analyze, and mitigate the top threats to cloud computing, as defined in the CSA Top Threats reports. The methodology consists of six steps: scope definition, threat identification, technical impact identification, business impact identification, risk assessment, and risk treatment. Each of these provides different insights and visibility into the organization's security posture.1 The technical impact identification step involves determining the impact on confidentiality, integrity, and availability of the information system caused by each threat. Confidentiality refers to the protection of data from unauthorized access or disclosure. Integrity refers to the protection of data from unauthorized modification or deletion. Availability refers to the protection of data and services from disruption or denial.2 An integrity breach occurs when a threat compromises the accuracy and consistency of the data or system. An integrity breach can result in data corruption, falsification, or manipulation, which can affect the reliability and trustworthiness of the data or system. An integrity breach can also have serious consequences for the business operations and decisions that depend on the data or system.3 In this case, the cybersecurity criminal was able to access an encrypted file system and overwrite parts of some files with random data. This means that the data in those files was altered without authorization and became unusable or invalid. This is a clear example of an integrity breach, as it violated the principle of ensuring that data is accurate and consistent throughout its lifecycle.4 References := CCAK Study Guide, Chapter 4: A Threat Analysis Methodology for Cloud Using CCM, page
811; What is CIA Triad? Definition and Examples2; Data Integrity vs Data Security: What's The Difference?3; Data Integrity: Definition & Examples

In multi-cloud environments, organizations use cloud services from multiple providers. This can lead to challenges in maintaining visibility and control over the data and services due to the varying management tools, processes, and security controls across different providers. The complexity of managing multiple service models and the reliance on different cloud service providers can reduce an organization's ability to monitor and control its resources effectively, thus increasing the risk of reduced visibility and control.
Reference = The information aligns with the principles outlined in the CCAK materials, which emphasize the unique challenges of auditing the cloud, including ensuring the right controls for confidentiality, integrity, and accessibility, and mitigating risks such as those associated with multi-cloud environments12.