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Public Cloud Security Explained

Public cloud security describes establishing cybersecurity measures to secure public cloud environments accessible to multiple users or organizations.

Wiz Experts Team
8 min read

What is public cloud security?

Public cloud security describes establishing cybersecurity measures to secure public cloud environments accessible to multiple users or organizations. Many businesses depend on cloud service providers (CSPs) like AWS, Google Cloud, and Azure to implement security measures for robust data protection in a public cloud environment. However, sole reliance on CSPs for public cloud security isn’t enough. Cybersecurity is a shared responsibility and a continuous and collaborative effort. When both cloud security teams and in-house teams take a proactive approach to cloud security, organizations are more likely to quickly identify and rectify potential weaknesses in public cloud environments.

The nuances of public cloud security are different from private cloud and hybrid cloud security. Private cloud security involves storing and securing data and applications in a dedicated cloud environment on-premises or with a third-party services provider. Private cloud networks are completely isolated from other organizations, and this multi-tenancy ensures a higher level of security. Hybrid cloud security, on the other hand, involves securing the integrated infrastructure and seamless flow of data and applications between public and private clouds. Public cloud security involves both cloud services providers and customers working together to secure public cloud infrastructure accessible to multiple users and organizations. 

Public cloud security is critical to ensuring data security, achieving compliance with regulatory standards, safeguarding user privacy, and maintaining business continuity. According to Foundry's Cloud Computing Study 2023, 57% of companies are accelerating cloud migration, and many are defaulting to cloud-based services whenever they upgrade or purchase new technical capabilities. The challenge that companies face is that 45% of data breaches are cloud based, as revealed by the Cost of a Data Breach Report 2023. The fact that 98% of IDC-surveyed organizations experienced a cloud data breach in 2021 spotlights how important public cloud security is. 

Understanding public clouds

The public cloud computing model made famous by cloud service providers like Google Cloud Platform (GCP) and Amazon Web Services (AWS) makes services and resources available to both individual users and organizations in real time. Public cloud resources include applications, virtual machines, arrays or workloads, and storage. The key characteristics of public cloud services include accessibility, multi-tenancy, pay-as-you-go pricing, reliability, scalability, and self-service.

There are three types of public cloud service models: 

  • Infrastructure as a service (IaaS): IaaS service models offer a range of on-demand compute and storage resources without the hassle of infrastructure maintenance. 

  • Platform as a service (PaaS): PaaS solutions include computing platforms, components, tools, and services for developers to use in every step of software development lifecycles (SDLCs), from build to deployment. 

  • Software as a service (SaaS): SaaS providers enable enterprise personnel to commission and access a variety of applications via web browsers. Examples of typical SaaS applications include productivity and videoconferencing apps. 

Enterprises navigate complex public cloud security threats as a trade-off for the numerous transformative benefits that IaaS, PaaS, and SaaS solutions bring, such as low upfront costs, agility and operational speed, resource elasticity, scalability, and performance consistency. Public cloud models also provide enterprises with access to the latest cutting-edge innovations and help them expand to new global markets. 

Public vs. private cloud security: Essential differences among public, private, and hybrid clouds

The public vs. private cloud debate is a common one. It’s important to remember that all cloud service models—public, private, and hybrid—have advantages and disadvantages. The key to meeting your cloud security responsibilities is to know what each model entails.

The following table illustrates the differences among public, private, and hybrid clouds:

FeaturesPublic CloudPrivate CloudNew Column 1
OwnershipCSPEnterpriseEnterprise
AccessEveryoneVery fewSome
CostsLow to mediumHighMedium to high
Customization and controlLowest controlHighest controlModerate control
ComplianceWeak to mediumStrongMedium to strong
Data sovereignty and localizationDifficultEasyModerately difficult
Ease of managementEasyDifficultAverage
PerformanceLow to mediumVery highHigh
Resource sharingSharedNot sharedPartially Shared
SecurityLow to mediumHighMedium to high
SustainabilityLowHighMedium

Public cloud security risks

Public cloud security can be a complex space to navigate. Understanding the threat landscape is the first step to securing your public cloud. Below are some of the most pressing public cloud security risks that businesses are likely to face. 

  • Misconfigurations: Incorrect security settings in public cloud resources can result in a multitude of high-risk vulnerabilities. Misconfigurations include suboptimal IAM controls, unpatched applications, exposed resources, and weak default settings. Neglected misconfigurations can lead to the exposure and exfiltration of sensitive data.

  • Lack of visibility and control: The constant commissioning of public cloud resources, both official and unofficial, in agile development environments means that enterprise cloud infrastructures can become overwhelmingly complex. This makes visibility and governance a challenge because enterprises might struggle to get a unified and comprehensive view of their public cloud resources. 

  • Multi-tenancy: Most SaaS and PaaS applications are multi-tenant, which means that they are susceptible to cross-tenant vulnerabilities like ExtraReplica and Hell’s Keychain. Poor security boundaries in cross-tenant applications can result in more lateral damage during security breaches. Tenant isolation is a viable solution, but there is a noticeable lack of standardized tenant isolation frameworks, tools, and best practices. 

  • Access management: The proliferation of public cloud resources introduces numerous security challenges related to access. Enterprises need to have complete control over which digital identities have access to what resources. Any deviation from zero-trust principles can lead to data breaches, account takeovers, and malware injections. 

  • Shadow IT: Public cloud resources are simple and affordable to purchase and activate. This means that employees are increasingly commissioning public cloud resources without IT approval, typically to sidestep complex authorization processes, self-optimize performance, and solve problems quickly. IT resources that are unofficially commissioned are called shadow IT and are difficult to discover, manage, and secure.

  • Insecure interfaces and APIs: APIs are the secret behind the seamless integration of disparate public cloud applications. While APIs can significantly accelerate digital environments, they are also responsible for an increase in an enterprise’s attack surface. (Misconfigurations in APIs are a common vulnerability exploited by threat actors to breach defenses.)

  • Insider threats and unauthorized access: Public cloud security risks are often exacerbated by insider threats. Malicious insiders can take advantage of existing cloud vulnerabilities to access crown jewel assets. Negligent insiders are just as damaging because they can unknowingly widen the attack surface. 

  • Advanced persistent threats (APTs): An APT is a type of advanced attack where threat actors breach cloud environments and remain there for long periods to exfiltrate data and cause lateral damage. APT attacks are complex and typically are carried out by experienced and organized cyber criminals. 

  • Distributed denial-of-service (DDoS) attacks: Most CSPs do offer some kind of protection against DDoS attacks. However, the more advanced DDoS attacks can easily bypass default security settings. It’s important to remember that defending public cloud infrastructures from DDoS attacks is not a top priority for CSPs and that there’s little to no DDoS-centric coverage in service-level agreements (SLAs).

The top 11 best practices for public cloud security

Ensuring public cloud security depends on strict adherence to security best practices. Let's take a look at the top 11 public cloud security best practices.

1. Understand the shared responsibility model

The shared responsibility model clearly delineates public cloud security responsibilities and helps you understand which areas of cloud security your CSP will cover, which areas you will take care of, and where there needs to be a collaborative effort. Public cloud responsibilities include IAM, data accountability, network controls, and endpoint protection. 

2. Establish robust access controls

Make sure that every user in your public cloud environment has only the bare minimum access required to perform their essential tasks. In the hands of a threat actor, overprivileged user accounts can be disastrous and lead to data breaches, many of which can go undetected for long periods. 

3. Leverage multi-factor authentication (MFA)

Embrace zero-trust principles in your public cloud environments. Make sure that every user has to provide multiple sets of credentials to access critical resources. (This is especially important for companies that have remote or distributed workforces.)

Adaptive MFA can also be a powerful tool because it acknowledges a more holistic context behind every access request, making it easier to red-flag anomalous behavior. Adaptive MFA takes MFA to the next level by using contextual information and risk analysis to determine the level of authentication required for a specific login attempt. The authentication process is adapted based on threat intelligence, user behavior, and environmental factors (network, location, and device characteristics). 

Implementing adaptive MFA can help companies avoid MFA fatigue attacks, like the one suffered by Uber, where threat actors who had employee credentials overwhelmed their targets with MFA requests until access was granted. 

4. Secure APIs and endpoints

Your APIs can be highly susceptible to bugs and vulnerabilities that can be exploited by threat actors to gain access to your system. Ensure protection by encrypting APIs, implementing role-based access controls (RBAC), and establishing rate limits.

5. Encrypt data in motion and at rest

Data breaches are almost an inevitable part of modern IT. However, not all data breaches have to be damaging. Encrypt your data so that no illegitimate user can read or leverage sensitive information even if they manage to access it. 

6. Update and patch regularly

Harden your security posture by patching out-of-date software regularly. Your ideal patch management lifecycle should include the following steps: First, develop your inventory. Second, identify, prioritize, test, deploy, and document the patching process. 

7. Implement network security protocols

Network security protocols can keep threat actors and illegitimate users from accessing or reading ported data. Examples of network security protocols include hypertext transfer protocol secure (HTTPS) and secure sockets layer (SSL). 

8. Leverage platforms like CNAPP and CSPM

The right cloud native application protection platform (CNAPP) solution can help you consolidate your cloud security stack and fortify your public cloud environments in a unified, affordable, and efficient manner. 

Always remember: The most effective CNAPP solutions don’t just identify and remediate public cloud vulnerabilities; they meticulously prioritize them to make sure that non-critical vulnerabilities don’t take up your valuable time and resources. 

CNAPP and CSPM tools can help you avoid data breaches like the incident in August 2023 where Topgolf Calloway, a US-based sports manufacturing enterprise, had 1.1 million of their customers’ records exposed. 

9. Closely monitor cloud resources and respond to security events

You must constantly monitor and scan cloud resources to make sure vulnerabilities don’t go unnoticed. Most importantly, ensure that high-risk and critical vulnerabilities are remediated in real time. The longer a vulnerability lingers in your public cloud, the higher the chance that a data breach will occur—or has already occurred. 

10. Secure the software development lifecycle (SDLC)

Shift left to empower your DevOps engineers and integrate vulnerability management early in your SDLCs. Doing so will help to tackle security vulnerabilities and risks right away and help to reduce the possibilities of large-scale security incidents and data breaches. 

11. Engage in regular vulnerability assessments and penetration tests

Regularly challenge your cloud security posture and vulnerability management ecosystem to find any weak spots. The simplest way to do this is by conducting vulnerability assessments to check your cloud environments for known vulnerabilities. Your organization should also simulate real-world attacks via penetration tests to test how robust your public cloud defenses are. 

The best way to approach public cloud security

Siloed security tools aren’t up to the task of modern cloud security. That’s why it’s essential to consolidate your public cloud defenses into a unified, cloud native solution. Wiz’s CNAPP solution can help you scan your cloud environments, remediate the most critical vulnerabilities, optimize SDLCs, and rapidly accelerate your business. 

Learn about our industry-leading cloud security platform: Get a demo now, and see for yourself how Wiz can help meet your organization’s unique cloud security needs.

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