Terraform Security: State Protection, Policy Scanning, and Drift Detection
Part of the Cybersecurity Skills Guide — This article is one deep-dive in our complete guide series.
By HADESS Team | February 28, 2026 | Updated: February 28, 2026 | 5 min read
Terraform manages your infrastructure. If your Terraform state file leaks, an attacker knows every resource, every IP, every connection string in your environment. If your Terraform code is insecure, you automate the deployment of vulnerable infrastructure at scale.
State File Protection
The Terraform state file contains the full truth about your infrastructure, including sensitive outputs like database passwords, API keys, and private IPs. Protecting it is non-negotiable.
Never store state locally for shared infrastructure. Use a remote backend with encryption and access controls:
“hcl terraform { backend "s3" { bucket = "myorg-terraform-state" key = "production/terraform.tfstate" region = "us-east-1" encrypt = true dynamodb_table = "terraform-lock" kms_key_id = "alias/terraform-state" } } `
Key requirements:
- Enable encryption at rest with a customer-managed KMS key
- Enable versioning on the state bucket — you need to recover from bad applies
- Use state locking (DynamoDB for S3, built-in for Terraform Cloud) to prevent concurrent modifications
- Restrict access with IAM policies. Only your CI/CD pipeline and designated operators should read or write state
- Never commit state files to Git. Add .tfstate
and.tfstate.backupto.gitignore
Checkov and Policy Scanning
Writing secure Terraform requires checking configurations against security benchmarks. Checkov scans Terraform code (HCL and plan files) for misconfigurations before anything gets deployed.
`bash`
checkov -d . --framework terraform
Common findings:
- S3 buckets without encryption or public access blocks
- Security groups with 0.0.0.0/0
ingress rules - IAM policies with wildcard permissions
- RDS instances without encryption or backup
Integrate Checkov into your CI pipeline. Fail the build on high-severity findings. Use custom policies for org-specific rules:
`python
from checkov.terraform.checks.resource.base_resource_check import BaseResourceCheck
from checkov.common.models.enums import CheckResult
class EnsureTagging(BaseResourceCheck): def __init__(self): super().__init__(name="Ensure resources have required tags", id="CUSTOM_001", categories=[], supported_resources=["aws_instance", "aws_s3_bucket"])
def scan_resource_conf(self, conf): tags = conf.get("tags", [{}])[0] return CheckResult.PASSED if "owner" in tags else CheckResult.FAILED `
Other tools worth considering: tfsec, Terrascan, and Snyk IaC. Use what integrates best with your pipeline.
Module Pinning
Terraform modules from the public registry or Git repositories should be version-pinned:
`hcl`
module "vpc" {
source = "terraform-aws-modules/vpc/aws"
version = "5.1.2" # Pin exact version
}
Never use version = “>= 5.0.0” for production modules. A new major version could change behavior or introduce insecure defaults. For Git-sourced modules, pin to a commit hash or tag — not a branch.
Review module source code before adoption. Public modules are community-maintained and may contain insecure defaults or unnecessary permissions.
Drift Detection
Infrastructure drift happens when someone modifies resources outside of Terraform — through the cloud console, CLI, or another tool. Drift means your state file no longer matches reality, and your security controls may no longer be applied.
Detect drift with terraform plan runs on a schedule:
`bash
terraform plan -detailed-exitcode
Exit code 2 means drift detected
“
Automate this in CI. Alert when drift is detected. Common drift patterns that indicate security issues:
- Security group rules added manually
- IAM policies modified outside Terraform
- Encryption settings changed on storage resources
- Public access enabled on resources that should be private
Terraform Cloud and Spacelift offer built-in drift detection with notifications.
Related Career Paths
Terraform security skills are required for DevSecOps and Cloud Security Engineer roles. Infrastructure-as-code security is a core competency in both paths. Check the skills page to map your current abilities.
Next Steps
- Assess your infrastructure-as-code security skills
- Build a certification roadmap covering Terraform and cloud security
- Practice in a workspace with Terraform security scanning scenarios
- Search for roles requiring Terraform and IaC security expertise
- Benchmark your market value for infrastructure security positions
Related Guides in This Series
- Ansible Security: Vault Encryption, Access Control, and Playbook Hardening — HADESS | 2026
- ArgoCD Security: RBAC, SSO, and GitOps Access Control — HADESS | 2026
- CI/CD Security: Pipeline Hardening and Supply Chain Integrity — HADESS | 2026
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—
HADESS Team consists of cybersecurity practitioners, hiring managers, and career strategists who have collectively spent 50+ years in the field.
