Shared Responsibility Model in the Cloud

CSPs have embraced a shared responsibility model to define the security responsibilities for different components of the architecture.

Securing cloud infrastructure necessitates a shift in mindset, moving away from traditional elements like firewalls, VPNs and servers, and focusing on workloads, buckets and blobs, and collaborating with external cloud service providers (CSP). Major CSPs such as AWS, Azure, and GCP have embraced a “shared responsibility model” to define the security responsibilities for different components of the architecture.

What is the shared responsibility model?

As organizations increasingly embrace cloud infrastructure and venture into multi-cloud environments, understanding and implementing the shared responsibility model becomes essential for understanding the responsibilities of both the provider and the customer in securing cloud infrastructure. However, these models present challenges that organizations need to address to ensure comprehensive cloud security. In this blog post, we will delve into the concept of shared responsibility in multi-cloud environments and provide actionable solutions to enhance cloud security posture.

It's important to note that the shared responsibility model may vary from one provider to another. The areas designated as the provider's responsibility by one CSP may be considered the customer's responsibility by another, or in some cases, the responsibility may be shared.

Understanding the shared responsibility model

The shared responsibility model defines the division of security responsibilities between the cloud service provider and the customer. Leading providers have distinct models that outline their respective areas of responsibility. For example, AWS focuses on securing the host operating system, virtualization layer and physical security of servers, while customers are responsible for network controls, configurations, identity and access management (IAM) and customer data. GCP similarly assigns infrastructure security to the provider, while customers assume responsibility for securing configurations, access policies, and content stored in the cloud.

Why are shared responsibility models important?

Shared responsibility models are crucial in cloud infrastructure security for several reasons. They ensure that both the cloud provider and the customer actively contribute to maintaining a secure cloud environment. They promote clarity, risk reduction, compliance adherence, collaboration and flexibility, ultimately enhancing the overall security and resilience of the multi-cloud deployment.

Clarity of responsibilities

In a cloud or multi-cloud environment (where multiple CSPs are involved), the shared responsibility model helps define and establish clear boundaries of responsibilities between the cloud provider and the cloud customer (organization or user). It outlines the areas where the cloud provider is responsible for security and where the customer needs to take ownership.

Mitigating security risks

The shared responsibility model ensures that security responsibilities are distributed between the cloud provider and the customer, reducing overall security risk. The cloud provider typically takes care of the security of the underlying infrastructure, such as physical site security, network and host. The customer, on the other hand, is responsible for securing their applications, data, operating systems and network configurations.

Compliance and regulatory requirements

Many industries and organizations have specific compliance and regulatory requirements regarding data security and privacy. The shared responsibility model allows organizations to understand the security controls implemented by the cloud provider and assess whether those controls align with their compliance needs. It enables the customer to fulfill their compliance obligations by implementing the required security measures within their own responsibility domain.

Collaboration and partnership

The shared responsibility model fosters collaboration and partnership between the cloud provider and the customer. It encourages organizations to actively participate in the security of their cloud deployments by implementing best practices, following security recommendations and leveraging the security tools and services provided by the cloud provider. This collaboration helps create a more secure environment and promotes a shared understanding of security objectives.

Flexibility and scalability

Multi-cloud environments offer flexibility and scalability for organizations to leverage different cloud providers based on their specific requirements. The shared responsibility model accommodates this flexibility by providing a consistent framework for security regardless of the chosen cloud provider. This allows organizations to maintain a consistent security posture across multiple clouds and easily adapt to changes or additions to their cloud infrastructure.

Three types of shared responsibility models

There are three types of shared responsibility models:

1. Software as a service (SaaS)
2. Platform as a service (PaaS)
3. Infrastructure as a Service (IaaS)

It's important to note that while the cloud provider assumes certain responsibilities in each model, they typically provide security features, tools and guidance to assist the customer in fulfilling their responsibilities. Additionally, the specific division of responsibilities may vary between different cloud providers, so it's crucial for organizations to review and understand the shared responsibility model defined by their chosen CSP.

Software as a service

In the SaaS model, the cloud provider delivers software applications over the internet, typically accessed through a web browser. With SaaS, the cloud provider assumes the highest level of responsibility for security, as they manage the entire software stack including infrastructure, applications and data. The customer's primary responsibility lies in managing and securing their own data and user access to the SaaS application. This includes tasks such as setting strong passwords, implementing multi-factor authentication (MFA) and defining access controls for their users.

Platform as a service

PaaS provides a platform or environment for developing, running and managing applications without the need to manage the underlying infrastructure. In the PaaS model, the cloud provider is responsible for securing the underlying infrastructure, including the operating system, network infrastructure and runtime environment. The customer is responsible for securing the applications they develop and deploy on the platform. This includes tasks such as securing application code, managing access controls and implementing necessary security configurations within their applications.

Infrastructure as a service

IaaS offers virtualized computing resources over the internet, including virtual machines, storage and networking capabilities. In the IaaS shared responsibility model, the cloud provider is responsible for the security of the underlying infrastructure such as physical security, network infrastructure and hypervisor security. The customer assumes a higher level of responsibility, as they have control over the operating systems, applications and data running on virtual machines.

How to apply the shared responsibility model

Applying the shared responsibility model involves a systematic approach to ensure that security responsibilities are properly distributed and implemented.

There are some important steps to apply the shared responsibility model effectively:

• Understand the model: Begin by thoroughly understanding the shared responsibility model provided by your CSP. Review their documentation, security guidelines and any specific policies related to security responsibilities. Gain a clear understanding of what aspects of security are covered by the CSP and what areas you, as the customer, are responsible for.
• Assess security requirements: Identify your organization's specific security requirements and compliance obligations. Determine the sensitivity of your data, the level of access control needed and any industry or regulatory standards that must be met. This assessment will help you determine which security controls need to be implemented within your responsibility domain.
• Implement security controls: Based on the shared responsibility model and your security requirements, implement the necessary security controls within your own infrastructure, applications and data. This includes activities such as configuring firewalls, implementing encryption, applying access controls, regularly patching systems and conducting vulnerability assessments. Follow best practices and industry standards to ensure a robust security posture.
• Centralize identity management: Consider using a centralized IAM security solution to manage user identities and access across multiple cloud providers. This allows for consistent enforcement of security policies, simplifies user provisioning and deprovisioning, and enhances visibility and control over user access.
• Collaborate with the CSP: Engage in collaboration with your CSP to leverage the security tools, services and expertise they offer. Regularly communicate with your CSP to stay updated on their security measures, patches and recommendations. Utilize any security features or services provided by the CSP to enhance the security of your cloud deployments. This collaboration ensures a shared understanding of security objectives and promotes a stronger security posture.
• Continuously monitor and improve: Security is an ongoing process so it's crucial to continuously monitor, assess and improve your security controls. Regularly monitor and analyze logs, implement intrusion detection systems and conduct security audits. Stay informed about emerging threats, vulnerabilities and updates from your CSP. Continuously evaluate and refine your security measures to address new risks and maintain a proactive security approach.

Following these steps, organizations can effectively apply the shared responsibility model, establish a comprehensive security framework and ensure a collaborative approach to securing their cloud deployments. Regular reviews and updates to the security strategy based on evolving threats and compliance requirements are also essential to maintaining a strong security posture over time.

Responsibility model best practices

To enhance cloud security in a multi-cloud environment, organizations must take proactive measures like ensuring clarity regarding the shared responsibility model throughout the organization, emphasizing the division of security responsibilities and DevSecOps. It’s important to promote understanding of different cloud service models and their implications for security ownership.

In addition, you need to put your money where your mouth is! Invest in cloud expertise by allocating resources to develop and expand cloud expertise within the organization. Foster continuous learning and training programs to empower teams in managing and securing cloud infrastructure effectively.

Finally, organizations must always supplement native tools. While native security tools provide a foundation, augment them with specialized cloud security solutions that address issues more deeply and holistically.

Challenges in implementing the cloud shared responsibility model

Securing cloud infrastructure in a multi-cloud environment requires a comprehensive understanding of the shared responsibility model. Cloud providers have clearly defined the division of security responsibilities between themselves and their customers. However, organizations face several challenges when it comes to effectively implementing and managing their share of the security responsibilities.

One of the key challenges is the lack of clarity surrounding the shared responsibility model. Many cloud customers are unaware of the model or misunderstand their own security obligations. This lack of understanding can lead to gaps in security and increase the risk of data breaches. It is crucial for organizations to educate themselves about the model and ensure that they have a clear understanding of their responsibilities.

Another challenge is the lack of cloud expertise within organizations. Cloud migration and digital transformation have accelerated in recent years, but many companies are still in the process of developing their internal knowledge and skills related to cloud security. This lack of expertise can make it difficult for organizations to effectively address the security challenges and implement proper cloud security practices. Investing in training and hiring skilled professionals can help bridge this gap and strengthen the organization's security posture.

While cloud providers offer some security tools, they may not fully cover the customer's security responsibilities or address all the specific needs of a multi-cloud environment. Organizations should consider leveraging third-party solutions and vendors that offer unified multi-cloud security solutions, enabling them to gain a comprehensive and consistent view across all their cloud environments.

The decentralized nature of security ownership within organizations adds complexity. Different divisions, departments and roles are involved in cloud infrastructure security, leading to fragmented decision-making and siloed security practices. Organizations need to establish clear lines of communication and collaboration to ensure that security responsibilities are effectively coordinated and implemented throughout the organization.

Understanding and effectively managing shared responsibility in a multi-cloud environment is essential for ensuring robust cloud security. By addressing the challenges of clarity, cloud expertise, tooling and ownership, organizations can reduce security risks, mitigate the likelihood of data breaches and maintain compliance. Embracing an identity-focused approach, implementing process automation and leveraging comprehensive security solutions will enable organizations to take control of their cloud security and protect their valuable assets in the ever-evolving cloud landscape.

Tenable Cloud Security

Tenable Cloud Security offers a comprehensive, identity-first cloud-native application protection platform (CNAPP) to supplement native tools provided by AWS, Azure and GCP. The agentless solution unifies and automates asset discovery, risk analysis, runtime threat detection and compliance — across cloud infrastructure, workloads, identities and data. It identifies, prioritizes and remediates security and compliance flaws with pinpoint accuracy.

To help organizations meet organizational requirements of the shared responsibility model, Tenable includes entitlement management, cloud security posture management (CSPM), runtime cloud workload protection, infrastructure as code (IaC) scanning and Kubernetes posture management to simplify cloud security practices with a fully integrated view into what matters and automated step-by-step remediation.