Top 10 AWS Security Mistakes Early-Stage Startups Make

Early-stage startups move fast. Security often gets deferred. But AWS security mistakes compound quickly—and when investors or enterprise customers ask for a security review, gaps become deal-breakers. Here are the top 10 mistakes I see, and how to avoid them.

1. Overly Permissive IAM Roles

The default: broad roles that "just work." The risk: a compromised service or developer account can access far more than intended. Fix: implement IAM least privilege. Grant only the permissions each role needs. Use policy conditions where possible. Review and tighten regularly.

2. Secrets in Code or Environment Variables

Hardcoded API keys, database passwords in .env files committed to Git—these leak. Fix: use AWS Secrets Manager or Parameter Store. Rotate secrets. Never commit credentials. Use IAM roles for AWS service-to-service auth where possible.

3. Unencrypted Databases

RDS, DynamoDB, or S3 without encryption at rest. Data breaches and compliance failures follow. Fix: enable encryption at rest for all data stores. Use KMS. Encryption in transit (TLS) is baseline.

4. Public S3 Buckets

Misconfigured bucket policies that allow public read or write. I've seen startups leak customer data this way. Fix: block public access by default. Explicitly allow only what's needed. Audit bucket policies regularly.

5. No WAF or Rate Limiting

APIs exposed to the internet with no protection. DDoS, abuse, and cost explosions. Fix: use AWS WAF, CloudFront, or API Gateway throttling. Implement rate limits. Monitor for anomalous traffic.

6. No Cost Alerts

AWS bills that spiral without warning. Forgotten resources, runaway Lambda, or expensive AI API calls. Fix: set billing alerts. Use Cost Explorer. Tag resources. Establish cost governance early.

7. Default VPC and Open Security Groups

Using default network configs with permissive rules. Fix: use custom VPCs. Restrict security groups to least privilege. Segment environments. No 0.0.0.0/0 unless absolutely required.

8. No Audit Logging

CloudTrail disabled or not monitored. When something goes wrong, you have no trail. Fix: enable CloudTrail for all regions. Log to a separate account or S3 with retention. Set up alerts for suspicious activity.

9. Shared Credentials

One AWS account, everyone uses the same keys. No accountability, high blast radius. Fix: use IAM users or SSO with MFA. Prefer IAM roles. Avoid long-lived access keys.

10. Deferring Security Until "Later"

"We'll fix it before we scale." Later never comes—or it comes as a breach or failed due diligence. Fix: build security in from the start. An early baseline AWS security review identifies gaps when they're cheap to fix.

Next Steps

An AWS security baseline doesn't require enterprise budgets. It requires intent. Start with IAM, encryption, and logging. Add WAF and cost controls. A consultant who specializes in startup cloud security can accelerate the process and avoid costly mistakes.