Baseline assumption: You already have CloudTrail, basic CloudWatch alarms, and Config turned on. These add-ons layer threat detection and hygiene checks without turning your inbox into a landfill.
Enable first (org-wide)
- GuardDuty — managed threat detection from CloudTrail, DNS, and VPC telemetry. Turn on in all regions; centralise findings.
- Inspector — automated EC2 and ECR (image) vulnerability scanning. Start with critical accounts; tag scope if costs matter.
- Security Hub — aggregates security findings and benchmarks. Enable a small set of standards first; route to a ticket queue, not email.
Consider next (scoped)
- Detective — investigation graphs for GuardDuty findings. Useful if you actually follow up incidents; otherwise skip.
- Macie — S3 sensitive data discovery. Start with high-value buckets only.
- CloudWatch Synthetics (Canaries) — HTTP checks for critical endpoints. One check per user-facing service is enough.
Routing and noise control
- Centralise to an aggregator account; forward findings via EventBridge to a queue/incident tool.
- Map severity → response. Reserve paging for GuardDuty high-severity and a handful of infra alarms.
- Review and suppress known-good findings with documented justifications.
Costs (keep it boring)
- Start in critical accounts; expand gradually. Tag resources for chargeback.
- Scope data-heavy features (data events, Macie) to high-value targets only.
- Set explicit CloudWatch log retention; archive long-term to S3/Glacier.
Security gaps in Linux and cloud systems risk downtime, data compromise, lost business — and compliance failures.
With 20+ years’ experience and active UK Security Check (SC) clearance, I harden Linux and cloud platforms for government, corporate, and academic sectors — ensuring secure, compliant, and resilient infrastructure.