Overview
As an Information Security Analyst I’d enforce five layered controls to preserve/improve security during and after migration: Network Policies, RBAC, Image Scanning, Runtime Protection, and Secrets Management. Each control includes rationale, implementation steps, monitoring, and example tools.
1) Network Policies
- Why: Limits blast radius and east‑west lateral movement.
- Implement: Default deny all; allow only required pod-to-pod and pod-to-service flows via Kubernetes NetworkPolicy; enforce via Calico/Cilium.
- Monitor: Flow logs, denied policy events, netflow anomalies.
2) RBAC
- Why: Least privilege for users, service accounts, and controllers.
- Implement: RoleBindings scoped to namespaces, use OIDC integration for admins, avoid wildcard verbs/resources, use kube‑audit to detect over‑privileged bindings.
- Monitor: Review audit logs, alerts on cluster-admin grants.
3) Image Scanning
- Why: Prevent vulnerable/malicious images entering registry.
- Implement: CI pipeline scanning (Snyk/Clair/Trivy), block builds with high severity, sign images with Notary/TUF, enforce admission controller to reject unsigned/unscanned images.
- Monitor: Vulnerability trend dashboard, open CVEs per image.
4) Runtime Protection
- Why: Detect/mitigate compromises at runtime (e.g., process tampering, crypto-miners).
- Implement: EDR/container runtime security (Falco, Aqua, Sysdig Secure), enforce Seccomp, AppArmor, read‑only root FS, Linux capabilities minimization.
- Monitor: Runtime alerts, anomalous execs, filesystem changes.
5) Secrets Management
- Why: Prevent credential leakage and rotation gaps.
- Implement: Use Vault/Kubernetes external secrets, avoid Kubernetes secrets in plain etcd (enable encryption at rest), short-lived secrets, RBAC-scoped service accounts.
- Monitor: Secret access logs, attempted reads from unexpected namespaces.
Trade-offs & Metrics
- Balance strict policies with deployment agility via CI gating and staged rollout.
- Key metrics: blocked deployments, policy deny rates, number of high CVEs prevented, runtime incident counts, secret access anomalies.
This layered approach reduces attack surface, prevents bad artifacts from entry, enforces least privilege, and provides detection/response capability.
