Public Cloud Security: The Basics & 7 Ways to Secure Your Cloud

Public cloud security encompasses a wide range of measures and technologies designed to safeguard public cloud environments and their data.

July 31, 2023

What Is Public Cloud Security?

Public cloud security is a broad term that encompasses a wide range of measures, protocols, and technologies designed to safeguard public cloud environments and the data stored within them. 

As businesses increasingly migrate their operations to the cloud, understanding and implementing robust public cloud security becomes pivotal. It’s not just about protecting sensitive business data from hackers and cybercriminals, but also ensuring compliance with various data protection regulations.

The concept of public cloud security is not solely about technology. It also involves a change in mindset and the way organizations approach data protection. In traditional IT environments, businesses had full control over their infrastructure and data. However, in a public cloud environment, businesses share control with the cloud service provider, making security a shared responsibility. This shift requires a new way of thinking about data security and risk management.

Moreover, public cloud security is an evolving field. As cyber threats grow more sophisticated, so do the security measures needed to combat them. This means that businesses must stay up-to-date with the latest trends and developments in public cloud security, and continually review and adjust their security strategies accordingly.

In this article:

Shared Responsibility Model in Public Cloud Security

The shared responsibility model is a fundamental concept in public cloud security. It delineates the security responsibilities of the cloud service provider and the customer. Typically, the cloud service provider is responsible for securing the underlying infrastructure that supports the cloud services, while the customer is responsible for securing the data they store and process in the cloud.

However, the boundaries of responsibility can vary depending on the cloud service model. For instance, in an Infrastructure as a Service (IaaS) model, the customer has more security responsibilities than in a Platform as a Service (PaaS) or Software as a Service (SaaS) model. The general areas of responsibility are:

  • Data classification and accountability
  • Client and endpoint protection
  • Identity and access management
  • Application-level controls
  • Network controls
  • Host infrastructure
  • Physical security

In the diagram below, provided by the CIS, you can see how responsibility is shared for each of these areas across different cloud deployment models.

how responsibility is shared across different cloud deployment models
Image Source: Center for Internet Security

Public Cloud Security vs. Private Cloud Security

Public clouds are provided by third-party service providers over the internet and are shared by multiple users. These cloud service providers invest heavily in security measures, consistently updating and maintaining their infrastructure to prevent data breaches. However, compared to a private cloud hosted by an individual organization, they provide limited control over security, and present some additional risks.

Strengths of public cloud security include:

  • Economies of scale: Public cloud providers can invest substantially in security resources, including specialized staff and advanced technologies, which can often outmatch the resources available to individual companies.
  • Regular updates: Providers regularly update and patch their infrastructure to combat the latest threats, reducing the security management burden on customers.
  • Shared responsibility: The provider takes care of securing the underlying infrastructure, reducing the areas an organization needs to secure directly.

Weaknesses of public cloud security include:

  • Limited control: Customers have less control over security in the public cloud, as the security protocols are mainly defined and managed by the provider.
  • Multitenancy risks: Public cloud platforms operate on a multitenant architecture, meaning that multiple customers’ data and applications share the same infrastructure, which could potentially expose sensitive data if isolation controls fail.
  • Compliance challenges: For businesses operating in heavily regulated industries, achieving compliance on public clouds can be more challenging due to the shared control over data and infrastructure.

Private clouds are owned and used exclusively by a single organization. They can be located on-premise or hosted by a third-party service provider. However, the key point is that the infrastructure is dedicated to a single organization, allowing for increased control over data and security.

Strength of private cloud security include:

  • Greater control: Private clouds offer businesses a higher level of control over their data and security, enabling them to tailor their infrastructure to meet their specific needs.
  • Compliance and governance: Private clouds make it easier to comply with stringent regulations, especially for industries such as healthcare and finance. They allow companies to implement necessary security controls to meet specific data privacy and residency requirements.
  • Isolation: Private clouds provide a high degree of isolation, reducing the risks associated with multitenancy. This isolation minimizes the chance of data leakage or cross-contamination.

Weaknesses of private cloud security include:

  • Heavier investment in security: Private clouds require an organization to invest more heavily in security resources, including personnel, technology, and ongoing management.
  • Sole responsibility for security: With increased control comes increased responsibility. In a private cloud, the organization is fully responsible for securing both the data and the underlying infrastructure, leading to a higher security management burden.
  • Update frequency: Private clouds often don’t have the same frequent security patching and updates seen in public clouds, potentially leaving them more vulnerable to new threats.

Learn more in our detailed guide to cloud security scanner 

Common Threats to Public Cloud Security

Public clouds face numerous threats and risks. Understanding these threats is the first step in developing an effective security strategy.

Insecure Access Points

Insecure access points are interfaces that allow data to be accessed and potentially exploited by unauthorized individuals.

Insecure access points can occur due to weak authentication processes, inadequate network security, or poorly configured access controls. They provide an easy pathway for cybercriminals to infiltrate the cloud environment and carry out malicious activities.

Account Hijacking

Account hijacking is a serious threat to public cloud security. It occurs when an attacker gains control of a user’s cloud account, usually through credential theft or phishing. Once in control, the attacker can access sensitive data, manipulate applications, and even launch attacks against other users.

Account hijacking can cause significant damage, including data loss, unauthorized transactions, and business disruption. Therefore, it’s important to implement strong user authentication methods and educate users about the risks of phishing and other forms of social engineering.


Misconfigurations are a significant risk to public cloud security. They occur when cloud services are not correctly set up, leading to vulnerabilities that can be exploited by attackers.

Misconfigurations can arise from a lack of understanding of cloud security best practices, human error, or inadequate monitoring and auditing. They can lead to data breaches, unauthorized access, and other security incidents. Therefore, it’s critical to ensure that cloud services are properly configured and regularly audited for compliance with security best practices.

Denial of Service (DoS) Attacks

Denial of Service (DoS) attacks are another common threat to public cloud security. In a DoS attack, the attacker overwhelms a cloud service or cloud-based server with an excessive amount of traffic, causing it to become unavailable to legitimate users.

DoS attacks can disrupt business operations and cause financial losses. They can also be used as a distraction for other malicious activities.

Implementing Public Cloud Security Measures

To maintain a strong security posture, organizations must consider a holistic approach to public cloud security, including at least the following elements:

1. Identity and Access Management (IAM)

IAM is a crucial first line of defense in public cloud security. By controlling who can access your cloud resources and what they can do with them, you reduce the risk of unauthorized access and potential data breaches. This involves implementing strong user authentication, managing user permissions, and regularly reviewing access controls.

An IAM strategy should also include measures to deal with lost or stolen credentials, such as multi-factor authentication (MFA) and biometric verification. Furthermore, organizations should adopt a least privilege approach, granting users only the permissions they need to perform their duties.

2. Encryption

Data encryption is a non-negotiable aspect of public cloud security. It involves converting data into random gibberish, which can only be read by someone with the correct decryption key. This means that even if a hacker manages to steal your data, they won’t be able to understand or use it.

There are two primary types of encryption: at rest and in transit. Encryption at rest protects your stored data, while encryption in transit protects your data when it’s being moved from one location to another. Both types are essential for a robust public cloud security strategy.

3. Secure Configurations

Secure configurations are another critical aspect of public cloud security. This involves setting up your cloud services and applications in a way that minimizes vulnerabilities and risks. It includes tasks like disabling unnecessary services, limiting open network ports, and configuring user access controls.

One common mistake organizations make is leaving default configurations unchanged. These defaults are often not secure, and can provide an easy entry point for attackers. Therefore, it’s important to review and customize these configurations to align with your specific security needs.

4. Firewalls and Network Security

Firewalls are a key component of network security in the public cloud. They act as a barrier between your cloud resources and potential threats, monitoring and controlling network traffic based on predetermined security rules.

In addition to traditional firewalls, you should also consider implementing web application firewalls (WAFs). These provide additional protection for your web applications by detecting and blocking common web-based threats, such as SQL injection attacks and cross-site scripting.

5. Monitoring and Logging

Monitoring and logging are essential for maintaining visibility into your public cloud environment. By keeping track of who is accessing your resources and what they’re doing, you can identify unusual behavior that could indicate a security incident.

Monitoring tools provide real-time alerts about potential threats, while logging tools create a record of events for later analysis. These tools should be used in conjunction to provide a comprehensive view of your security posture.

6. Vulnerability Management

Vulnerability management is a proactive approach to public cloud security. It involves identifying, assessing, and mitigating vulnerabilities in your cloud environment before they can be exploited by attackers.

This process typically involves regular vulnerability assessments, patch management, and threat intelligence. By staying ahead of potential threats, you can significantly reduce your risk of a data breach.

Learn more in our detailed guide to cloud vulnerability

7. Compliance Management

Finally, compliance management is an often overlooked aspect of public cloud security. This involves ensuring that your cloud environment meets the necessary regulatory standards and industry best practices.

Compliance management can be complex, as it involves navigating a myriad of different regulations. However, it’s an essential part of public cloud security, as non-compliance can result in hefty fines and damage to your reputation.