How to conduct a cloud security audit: A step-by-step guide

Introduction

Cloud environments, while offering flexibility and scalability, come with their own set of security challenges. A cloud security breach can result in severe financial losses, making it crucial to regularly evaluate your cloud infrastructure for vulnerabilities.

Conducting cloud security audit helps ensure that your cloud-hosted applications and data are protected from unauthorised access and potential threats. These audits assess whether security controls are functioning as intended and identify any misconfigurations or weak points that could be exploited.

In this article, we talk in-depth about the importance of conducting cloud computing and auditing and how you can do it!

What is a cloud security audit?

A cloud security audit is a detailed review of the security measures in place within your cloud environment. It’s conducted to ensure that your organisation’s cloud setup meets industry security standards and is free from vulnerabilities.

During the audit, an external security auditor will gather information, run tests, and examine how your Cloud Service Provider (CSP) manages data security. Cloud services typically fall into three categories:

• Software as a Service (SaaS)
• Infrastructure as a Service (IaaS)
• Platform as a Service (PaaS)

These solutions allow businesses to store data and handle daily operations in the cloud. An AWS cloud security audit or Azure cloud security audit checks if these services are secure and compliant with relevant regulations. It helps uncover any risks or weaknesses that could lead to data breaches or security failures.

The audit also evaluates the security controls (technical safeguards) set by the CSP (Cloud Service Provider), such as AWS or Azure, and your company. This includes reviewing how well these controls protect sensitive data and how effective they are at preventing cyber threats. If gaps or issues are identified, addressing them quickly helps you avoid potential data loss or penalties for non-compliance with laws.

Why conduct a cloud security audit?

Cloud computing and auditing are critical for ensuring that your cloud infrastructure is safe and meets industry requirements. Regular audits help identify risks, assess security controls, and make sure your data is protected from potential threats. Here’s why you should conduct a cloud security audit:

1. Ensure compliance with regulations

A cloud security audit helps you verify that your cloud environment complies with relevant laws and industry standards. It identifies any compliance gaps and provides recommendations to fix them, helping you avoid penalties or legal issues.

2. Strengthen data security

An audit helps protect your data by evaluating security controls (measures to safeguard information). You can detect potential weaknesses, such as unauthorised access, and take steps to improve data security.

3. Improve access control

As employees join, leave, or change roles, it’s important to control who can access your cloud systems. A security audit checks that access is being managed responsibly. It ensures former employees no longer have access and that new hires are given the least amount of access needed.

4. Secure APIs and third-party tools

Most cloud environments rely on APIs (Application Programming Interfaces) and third-party tools to function smoothly. Each of these can pose security risks. A cloud security audit helps identify any weak spots in these tools and ensures they are properly secured.

5. Verify backup strategies

A cloud environment allows for easy backups, but backups are only useful if they’re done regularly and securely. A security audit ensures that all critical systems are backed up and that the backups are protected from unauthorised access or loss.

6. Prevent data loss

Cloud computing and auditing helps you assess the risk of data loss by identifying vulnerable areas where data might be exposed or at risk. Addressing these risks helps keep your cloud environment secure and ensures your data remains safe.

7. Optimise cloud resources

Beyond security, an audit can also help you identify unused or redundant cloud resources. By addressing these inefficiencies, you can reduce costs and optimise the use of your cloud infrastructure.

Preparation for the audit

Preparing for a cloud security audit involves ensuring that your cloud environment, security policies, and compliance measures are well-documented and up-to-date. This includes reviewing your existing security controls, identifying potential risks, and making sure all relevant stakeholders are aware of the audit process.

Moreover, proper preparation helps ensure a smooth audit, minimising disruptions and providing a clear picture of your cloud security posture. By addressing any gaps beforehand, you can be better positioned for a successful audit outcome.

6 Steps to conducting a cloud security audit

A cloud security audit helps identify and fix vulnerabilities in your cloud environment. Here are six key steps involved in conducting a cloud security audit:

1. Evaluate the cloud provider's security posture

Start by assessing your cloud service provider's security measures (CSP). This includes reviewing their security controls, policies, and compliance with industry standards. Engage with your CSP to understand how they handle data protection, encryption, and disaster recovery.

You’ll want to confirm that their security measures meet your organisation’s specific requirements and align with best practices like those outlined by the Cloud Security Alliance (CSA).

During this evaluation, gather relevant documentation, such as compliance reports and certifications (e.g., ISO 27001 or SOC 2), which verify the CSP's security practices. This initial review will help you identify potential risks and areas requiring further attention.

2. Determine the attack surface

Your attack surface refers to all the points where unauthorised users could potentially access your cloud systems. These include applications, cloud instances, and data storage areas. Because cloud environments are large and complex, mapping out your attack surface is essential to understanding where vulnerabilities might exist.

Use cloud monitoring and observability tools to identify assets across your cloud infrastructure. This step involves checking for any unapproved systems or applications that could create security risks (commonly referred to as shadow IT).

3. Set strong access controls

Unauthorised access is one of the most common cloud security threats. To protect your sensitive data, establish strict access controls to limit who can access different parts of your cloud environment.

Implement policies that require Multi-Factor Authentication (MFA) for all users and ensure passwords are strong and regularly updated. Additionally, administrative rights should be restricted to reduce the risk of misuse or accidental changes to security settings.

4. Develop external sharing standards

Data sharing is often necessary but must be controlled, especially when dealing with sensitive information. Create clear guidelines on how data can be shared externally, such as through shared drives or file-sharing tools. Start by applying strict security settings and loosening them only when absolutely needed.

Ensure that files containing Personally Identifiable Information (PII) or Protected Health Information (PHI) are not shared with external parties unless it’s essential. 

5. Automate patching

Regular patching is critical to keep your cloud environment secure. Patching refers to updating software to fix known vulnerabilities. However, keeping up with manual patching can be time-consuming and error-prone.

To streamline this process, you should adopt automated patch management tools that prioritise and apply patches to critical systems automatically.

6. Use SIEM to standardise cloud logs

SIEM systems help centralise and analyse security logs from various cloud environments. SIEM systems collect and organise log data, allowing you to monitor activity and detect suspicious behaviour.

By implementing SIEM, you can automatically generate reports that align with compliance requirements. This ensures that your audit process is efficient and that you maintain visibility across your cloud infrastructure.

Best practices for cloud security audits

Conducting cloud security audits effectively requires following specific best practices such as:

Define the scope

Start by identifying all cloud providers and services used within your organisation. Knowing exactly what you are auditing ensures that no critical area is left out. This includes understanding the architecture, services, and security controls provided by each cloud vendor.

Control access

It’s important to have a clear picture of who has access to your cloud infrastructure and at what level. Implement the principle of least privilege (giving users only the access they need to complete tasks). This minimises the risk of unauthorised access.

Monitor cloud activity

Implement continuous monitoring tools that track activity across your cloud environment. This includes logging all access, changes, and unusual behaviours. Also, automated monitoring tools can help you detect suspicious activity, which is crucial for identifying potential threats early.

Keep systems updated

Cloud environments are often exposed to security vulnerabilities, which makes regular patching critical. Ensure that all cloud services and applications are kept up to date with the latest security patches. Moreover, patch management should be automated where possible to avoid missing critical updates, as outdated systems can become easy targets for attackers.

Audit frequently

While annual or biannual audits are common, the frequency should depend on your specific needs. If you manage highly sensitive data or operate in a high-risk environment, more frequent audits may be required. Additionally, conduct audits after major changes to your cloud environment, such as adding new services or expanding cloud infrastructure.

Promote accountability

Make sure there is clear ownership over every security aspect and audit finding. Assign specific roles to individuals or teams responsible for addressing audit results and remediating security risks. When everyone knows their responsibilities, it ensures a faster and more effective response to any issues that arise, keeping your cloud environment secure.

Common challenges and how to overcome them

Cloud security audits are crucial to ensure that your data is safe and that your cloud environment complies with regulations. Below are the common challenges you may face during a cloud security audit and practical ways to address them.

1. Lack of visibility

Cloud environments are often complex, with various services spread across multiple providers. Each cloud provider (also called Cloud Service Provider or CSP) follows its own set of security practices, making it harder for auditors to gather the necessary data. Furthermore, these CSPs often provide limited access to key operational and forensic data, which is critical for audits.

How to overcome it:
Work closely with your CSP to align with their policies and ensure access to relevant information. Choose test cases carefully to avoid violating security rules, and maintain transparency to improve audit efficiency.

2. Encryption

Encryption plays a vital role in securing data, but it can also complicate audits. There are two ways to encrypt data in the cloud:

• On-premise encryption: Your organisation encrypts data before uploading it to the cloud.
• Provider encryption: The CSP handles the encryption process.

With on-premise encryption, you manage encryption keys internally, reducing the risk of cloud provider breaches. However, insider threats (malicious actions by internal employees) remain a concern. With provider encryption, the CSP manages the encryption, leaving your data vulnerable to any breaches that happen within the cloud provider’s environment.

How to overcome it:
For better auditability, encrypt your data internally and manage encryption keys independently from your CSP. This ensures full control over encryption processes, as recommended by the PCI DSS Cloud Special Interest Group.

3. Colocation

Many cloud providers use the same physical systems to store data from multiple organisations, which increases security risks. It also makes physical audits challenging, as auditors cannot easily access the physical servers to check security protocols.

How to overcome it:
Choose a cloud provider with mechanisms to prevent unauthorised access to shared resources and ensure proper controls to stop other tenants from gaining administrative privileges. This safeguards your data from unauthorised access or manipulation.

4. Lack of standardisation

Cloud environments often consist of multiple entities, including Virtual Machines (VMs), containers, and managed databases. The number of these entities can grow rapidly, which makes it difficult to keep track of everything during an audit. Moreover, constant changes in the cloud setup complicate the auditing process even further.

How to overcome it:
Standardise workloads by using a limited set of container and virtual machine images, making audits more efficient. This simplifies the process and helps identify key cloud entities that require auditing.

5. Scale and complexity

In traditional data centres, auditors could review a fixed number of servers. However, in cloud environments, the number of audited entities, such as physical hosts and containers, can grow exponentially. This growth makes it difficult to track and audit every entity, especially when new entities are added and removed frequently.

How to overcome it:
Automate and standardise processes, using controlled pools of resources like specific VM or container images. This simplifies audits and helps maintain control over your cloud environment.

Conclusion

Conducting regular cloud security audits is essential to safeguard your applications and data from unauthorised access and security threats. By following a structured approach, you can ensure that your cloud infrastructure is not only compliant with industry standards but also well-protected against potential vulnerabilities.

Moreover, regular audits not only help detect and address security gaps but also strengthen your organisation's overall security posture. By staying proactive and thorough in your auditing efforts, you can minimise risks, improve compliance, and build trust with stakeholders who rely on the security of your cloud environment.

Tata Communications provides end-to-end security solutions that enable organisations to secure their environments comprehensively and confidently. Our services ensure compliance, protect critical data, and deliver seamless visibility across your cloud infrastructure.

With decades of expertise and a proven track record in safeguarding enterprises, Tata Communications provides innovative, scalable, and reliable security solutions. Partner with us to fortify your cloud infrastructure and build a security-first approach to protect your organisation from evolving threats. Schedule a conversation with our experts and take the first step toward a secure cloud environment!