12. Security and Compliance at Scale

Security in AWS isn’t just about enabling encryption or passing an audit. It's about designing with visibility, delegation, and automation in mind. The primitives are powerful, but only if you're prepared to use them.

Many teams fall into the trap of thinking that the cloud is secure "by default" or that compliance is just a matter of ticking boxes post-migration. In reality, migrations introduce new security boundaries, new workflows, and a need to rethink ownership entirely.

• Application environments become ephemeral

• Public and private subnets matter more than firewall rules

• Encryption is expected, but must be enforced

• IAM defines blast radius, not just authentication

You gain power, but also complexity. And without careful upfront design, you risk re-migrating systems internally (e.g., moving services between subnets or refactoring access boundaries).

A well-prepared migration plan that uses tested, production-ready infrastructure modules can mitigate much of this. When those modules include secure defaults, appropriate logging, tagging, network layouts, and boundary controls, you're not relying on every engineer to reinvent best practices. You sidestep many of the most common mistakes simply by adopting patterns that have already been hardened by repeated use.

• IAM misconfigurations (overly permissive roles, unclear trust boundaries)

• Lack of audit trail (CloudTrail not enabled or improperly scoped)

• Secrets poorly managed (stored in env vars, not rotated, or exposed via logs)

• Shadow access from legacy systems still wired in

• S3 misconfigurations leading to unintentional exposure

• Encryption assumptions not enforced in RDS or EBS

• Teams unclear on shared responsibility (what AWS handles vs. what they own)

And one of the most painful: security teams being left out until after the fact, forced to play catch-up once workloads are already live.

• Stronger boundaries: between apps, teams, and environments

• Clear roles and responsibilities: who owns what, who sees what

• Repeatable patterns: for secrets, backups, and disaster recovery

But this only works if security is embedded up front. Waiting until post-launch means double work.

We’ve seen teams refactor their VPC structure or replatform parts of their system simply because they didn’t account for access paths, logging, or deployment models in the initial architecture.

When teams start with prebuilt infrastructure modules that already include these elements, they reduce risk without needing to learn from painful mistakes. These modules make secure design the default, not an afterthought.

• IAM + SSO: Enforce role-based access and minimize long-term credentials

• CloudTrail: Enable organization-wide auditing

• Secrets Manager: Rotate secrets safely without CI hacks

• Security Hub: Aggregate alerts and config drift across regions and accounts

• GuardDuty: Detect anomalous behavior (e.g. unusual API calls or traffic)

• ALB + WAF: Default edge architecture for web apps, with rule-based protections

Use these tools not as checkboxes, but as platform defaults. Bake them into Terraform, CI/CD, and onboarding.

• Own their own environment-level IAM policies

• Define their alerting thresholds

• Audit changes via CodePipeline or Git history

Zero Trust isn’t aspirational. It’s practical. But only if the teams building apps are aware of what they’re exposing and how they’re protected.

This requires training and standards, not just enforcement.

• Real-time posture monitoring replaces one-time audits

• Tagging and logging become non-negotiable

• Drift detection must be automated — configs will diverge over time

Trying to recreate old audit workflows won’t work. Instead, use tools like Security Hub, Config, and third-party CSPM (Cloud Security Posture Management) platforms to detect, alert, and track changes over time.

Security in AWS is not automatic — but it is achievable at scale.

Teams that plan for access control, observability, and architectural boundaries during migration avoid rework, delays, and late-stage panic.

The goal isn’t to harden everything to perfection. It’s to build a secure system you can actually evolve.