Cloud Security for Startups: AWS and GCP Basics

Understand the Shared Responsibility Model

Cloud providers secure the physical data centers, network, and hypervisor. You secure everything you put on top: operating systems, applications, data, access policies, and network configurations. On AWS, this means you manage EC2 security groups, IAM roles, and S3 bucket policies. On GCP, you manage VPC firewall rules, IAM roles, and Cloud Storage permissions. Never assume the provider handles your data security.

Lock Down IAM and Access

Use IAM roles instead of long-lived access keys. On AWS, attach policies to roles and assign them to EC2 instances or Lambda functions. On GCP, use service accounts with minimal permissions. Avoid using root or admin accounts for daily tasks. Enable multi-factor authentication (MFA) for all human users. Rotate keys regularly and audit unused access keys.

Example: If an application needs to read from an S3 bucket, create an IAM role with s3:GetObject permission only for that specific bucket. Do not attach s3:*.

Secure Your Network

Use Virtual Private Clouds (VPCs) to isolate resources. On AWS, define subnets and route tables. On GCP, configure VPC firewall rules that allow only necessary traffic. Do not open ports like 22 (SSH) or 3389 (RDP) to the internet. Use bastion hosts or VPNs for administrative access. For web applications, allow only HTTP/HTTPS from load balancers and block direct traffic to instances.

Set security groups (AWS) or firewall rules (GCP) to allow traffic only from specific IP ranges or other security groups. For example, an application tier should accept traffic only from the web tier's security group.

Encrypt Data at Rest and in Transit

Enable encryption for all storage services. AWS S3 offers server-side encryption (SSE-S3, SSE-KMS). RDS supports encryption at rest. On GCP, Cloud Storage encrypts data by default, and you can use CMEK for more control. Use TLS for all data in transit. Configure your load balancer to terminate TLS and redirect HTTP to HTTPS. Enforce encryption on database connections.

For sensitive data, consider client-side encryption before uploading to cloud storage.

Enable Logging and Monitoring

Centralize logs using AWS CloudTrail and GCP Cloud Audit Logs. Enable VPC flow logs to capture network traffic metadata. Set up CloudWatch (AWS) or Cloud Logging (GCP) alerts for suspicious activities like failed login attempts, unusual API calls, or large data transfers. Use a security information and event management (SIEM) tool if your team can manage it. Review logs at least weekly.

Plan for Incident Response

Create a written incident response plan. Define roles: who investigates, who communicates, who patches. Practice with tabletop exercises. Automate containment where possible. For example, use a Lambda function that automatically revokes a compromised IAM key. Keep snapshots of affected systems for forensics. Test your backup restoration process regularly.

Use Security Tools and Automate

Use AWS Config or GCP Security Command Center to detect misconfigurations. Enable AWS GuardDuty or GCP Cloud IDS for threat detection. Use Infrastructure as Code (Terraform, CloudFormation) to enforce security policies. Scan container images for vulnerabilities with Amazon ECR scanning or GCP Artifact Analysis. Regularly review your security posture with tools like Kyro, an AI penetration tester for SaaS. Point it at your app URL, and it hunts for real vulnerabilities continuously. Start a free scan.

For a broader view, see our SaaS Security Checklist.