Cloud security works differently from traditional security. The perimeter has dissolved. Resources are provisioned in minutes. APIs replace physical access. Understanding cloud security fundamentals is essential for any organisation using cloud services.
Identity and Access Management
In cloud environments, identity is the new perimeter. Who can access what, and how, determines security posture.
Principle of Least Privilege
Grant only the permissions needed for specific tasks. No more. Review and revoke unused permissions regularly.
Multi-Factor Authentication
Require MFA for all human access, especially privileged accounts. Password-only authentication is insufficient.
Role-Based Access
Define roles with specific permissions. Assign users to roles rather than granting individual permissions. Easier to manage and audit.
Service Accounts
Applications and services need identities too. Use service accounts with minimal permissions. Avoid long-lived credentials where possible—use short-lived tokens.
IAM Best Practices
- Never use root/owner accounts for daily operations
- Require MFA for console and API access
- Rotate credentials regularly
- Use identity federation (SSO) where possible
- Audit access regularly; remove unused permissions
Network Security
Virtual Private Cloud
Isolate resources in virtual networks. Control traffic flow with security groups and network ACLs. Don't put everything on public subnets.
Segmentation
Separate tiers: web, application, database in different subnets. Limit traffic between tiers to only what's required.
Ingress/Egress Control
Restrict inbound access to only necessary ports and sources. Control outbound traffic to prevent data exfiltration.
Private Connectivity
Use private endpoints for cloud services. Keep traffic within cloud network rather than traversing public internet.
Data Protection
Encryption at Rest
Encrypt stored data—databases, object storage, disks. Use cloud-managed encryption keys or bring your own.
Encryption in Transit
Use TLS for all network communication. Internal and external. No exceptions.
Key Management
Use cloud key management services (AWS KMS, Azure Key Vault, Google Cloud KMS). Proper key rotation. Access controls on keys.
Data Classification
Know what data you have and its sensitivity. Apply appropriate protections based on classification. Not all data needs the same level of protection.
Logging and Monitoring
Audit Logging
Enable cloud audit trails (CloudTrail, Azure Activity Log, GCP Audit Logs). Log all API calls, configuration changes, access events.
Centralised Logging
Aggregate logs centrally. Application logs, security logs, infrastructure logs. Enable analysis and correlation.
Alerting
Alert on security-relevant events. Configuration changes, access anomalies, suspicious activity. Don't just log—act.
Security Posture Monitoring
Use cloud security posture management (CSPM) tools. Continuously assess configuration against best practices. AWS Security Hub, Azure Security Center, GCP Security Command Center.
Common Misconfigurations
| Misconfiguration | Risk |
|---|---|
| Public storage buckets | Data exposure |
| Overly permissive security groups | Unauthorised access |
| Missing MFA on privileged accounts | Account takeover |
| Hardcoded credentials in code | Credential theft |
| Disabled logging | No breach detection |
| Unencrypted sensitive data | Data compromise |
Summary
Cloud security requires understanding the shared responsibility model and focusing on what you control: identity, network configuration, data protection, and monitoring. Most breaches result from misconfiguration, not sophisticated attacks.
Key priorities: implement strong identity controls with MFA, apply least privilege everywhere, encrypt data at rest and in transit, and maintain comprehensive logging and monitoring. Use cloud-native security tools to continuously assess your security posture.