Infrastructure as Code (IaC) drift detection is the line between control and chaos. Code defines resources. Reality changes. When live infrastructure no longer matches the IaC spec in your repository, you’ve lost truth. Drift can happen fast—manual changes in the cloud console, scripts run outside CI/CD, or configuration updates pushed without review. Every deviation is a potential vulnerability, a compliance gap, or an availability risk.
SAST—Static Application Security Testing—brings discipline to IaC analysis before deployment. It reads IaC files, parses every resource, and flags security risks and policy violations. It ensures that what you intend to build is secure in principle. But SAST alone cannot confirm that production matches code. Drift detection closes that gap. It is the runtime verification loop that measures deployed state against desired state and identifies mismatches instantly.
Modern IaC drift detection tools integrate directly with source control and CI/CD. They scan your Terraform, CloudFormation, Kubernetes manifests, or Pulumi code, then query actual cloud APIs to compare resources line by line. This hybrid approach—SAST for static validation, drift detection for dynamic truth—hardens both planning and execution. It keeps environments aligned with versioned intent, so security controls and networking policies stay consistent across the lifecycle.