What Is Cloud Computing and How Is It Secure: An Evergreen Explainer

What is cloud computing and how is it secure: answer-first overview

Cloud computing is on-demand delivery of IT resources over the internet from a cloud provider's pool of shared resources, including compute, storage, databases, networking, and software. You access services via web portals and APIs rather than owning physical infrastructure. Cloud security refers to the technologies, policies, controls, and practices that protect cloud data, applications, and infrastructure against threats. Security in the cloud follows a shared responsibility model: the provider secures the cloud infrastructure, while you secure what you use in it, such as configurations, identities, data, and applications. With correct setup and ongoing management, cloud platforms can be highly secure and resilient.

Cloud computing explained: core service and deployment models

Service models

Service models define where responsibility lies between you and the provider.

• Infrastructure as a Service (IaaS): You manage operating systems, middleware, runtime, and applications; the provider handles virtualization, servers, storage, and networking.
• Platform as a Service (PaaS): The provider manages infrastructure and platform layers (operating systems, runtime, databases); you focus on application code and data.
• Software as a Service (SaaS): The provider runs everything; you simply use the software via a browser or client.

Deployment models

• Public cloud: Multi-tenant services over the public internet, with the provider managing all infrastructure.
• Private cloud: Dedicated infrastructure for a single organization, on-premises or hosted, with more direct control.
• Hybrid cloud: Combination of public and private environments with orchestration between them.
• Community cloud: Shared infrastructure for a specific community with aligned concerns (compliance, jurisdiction).

Understanding which model you use shapes your security controls, since IaaS requires more security effort from you than PaaS or SaaS.

How the shared responsibility model defines cloud security

The shared responsibility model clarifies what the provider secures and what you must secure. The provider is typically responsible for the security of the cloud: physical data centers, hardware, storage, network infrastructure, and global edge locations. You are responsible for security in the cloud: customer identities, access management, OS and application patching, data encryption, network configuration, and endpoint security. The exact line varies by service model:

• IaaS: You secure operating systems, apps, data, and network settings; the provider secures virtualization and hardware.
• PaaS: The provider secures the runtime and OS; you secure app logic, configuration, and data.
• SaaS: The provider handles almost everything; your responsibilities are limited to user access, data governance, and secure use.

Clarifying responsibilities with your vendor in writing reduces risk and helps pass audits.

Key security capabilities you should expect from a cloud provider

Modern cloud platforms include a broad set of native security capabilities. These include encryption by default for data at rest and in transit, fine-grained identity and access management (IAM) with multifactor authentication (MFA), continuous monitoring and logging (such as activity trails and security events), threat detection via analytics and anomaly detection, network protections like firewalls and micro-segmentation, vulnerability scanning and patch management, and data loss prevention and backup/restore features. Evaluate providers against these capabilities and understand how they map to your controls and compliance needs.

How to secure your workloads in the cloud: practical guidance

Implement robust cloud security by design, not as an afterthought. Start with identity: enforce least-privilege IAM roles and MFA for all human and machine identities. Encrypt data at rest and in transit using strong keys; prefer provider-managed keys or bring your own keys when allowed. Manage configurations with infrastructure-as-code and guardrails; avoid default passwords and open access (e.g., unrestricted 0.0.0.0/0). Monitor continuously with centralized logging, alerting, and periodic audits; test backups and recovery procedures regularly. Train your teams on cloud-specific risks and establish a clear shared responsibility agreement with your provider.

Cloud security metrics and evidence: factual snapshot

Common cloud security risks and how to mitigate them

Recognize common risks and apply targeted mitigations to reduce exposure.

• Misconfigurations: Use policy-as-code, automated assessments, and least-privilege defaults to detect and block risky settings.
• Weak identity practices: Enforce MFA, strong passwords, and regular access reviews for both users and service principals.
• Insecure interfaces and APIs: Harden API permissions, use private endpoints, and apply rate limiting and input validation.
• Insider threats: Implement separation of duties, logging, and privileged access management to detect unusual activity.
• Data exposure: Classify data, encrypt consistently, and manage keys with defined rotation and access policies.
• Shared technology vulnerabilities: Stay current with provider updates and apply your own patching for guest OS and apps.

Compliance, certifications, and audits in the cloud

Cloud providers maintain a wide range of compliance certifications and attestations, which can simplify meeting regulatory requirements. Common programs include ISO 27001, SOC 2, PCI DSS, HIPAA, and GDPR. Review the provider's compliance reports and understand how your responsibilities map to each regime. You are typically responsible for implementing controls on your side (such as data classification, access governance, and encryption key management) even when the provider holds a certification. Maintain your own audit evidence: configurations, IAM policies, logs, and change records support audit readiness.

When to review and update your cloud security posture

Cloud security is not a one-time setup. Review your security posture regularly and whenever you change architecture, adopt new services, or face new threats. Recommended cadence includes quarterly configuration reviews, continuous monitoring with automated alerts, periodic penetration testing and red-team exercises, and annual reassessment of data classification and retention policies. Tie these activities to your identity and compliance frameworks to ensure durable protection over time.

Tags: cloud-security, cloud-computing, shared-responsibility