Terraform is a popular Infrastructure as Code (IaC) tool that allows users to define and manage cloud infrastructure in a declarative way.  However, like any tool, Terraform can introduce security risks if not used properly.

In this article, we will explore the most common security risks when using Terraform, the threat landscape and attack surface, how it can be exploited, and how users can stay secure by following Terraform security best practices.

What is Terraform and why Should I Use it?

Terraform is an open-source tool developed by HashiCorp that enables users to define and provision infrastructure resources across multiple cloud providers and on-premises environments. It allows organizations to treat infrastructure as code, bringing the benefits of version control, collaboration, and automation to infrastructure management.

By adopting Terraform and embracing the principles of Infrastructure as Code, organizations can achieve several benefits:

  • Consistency and repeatability: Infrastructure deployments become consistent and repeatable, eliminating the risk of manual errors and ensuring that the same configuration can be applied across different environments.
  • Version control and collaboration: Infrastructure code can be stored in version control systems, enabling teams to collaborate, track changes, and roll back to previous versions if needed.
  • Automation and scalability: Infrastructure deployments can be automated, allowing organizations to scale their infrastructure quickly and efficiently based on demand.
  • Auditing and compliance: Infrastructure code can be audited and reviewed for compliance with security and regulatory standards, ensuring that best practices are followed.

While Terraform offers a powerful and flexible solution for managing infrastructure, it is essential to address the security considerations associated with using the tool effectively.

Security considerations

As with any tool or technology, Terraform is not immune to security threats and challenges. It is crucial to understand the threat landscape and the potential risks associated with using Terraform.

By identifying these risks, organizations can implement appropriate security measures to mitigate them effectively.

Configuration errors

One of the primary security risks associated with Terraform is misconfigurations in the infrastructure code.

Misconfigurations can lead to vulnerabilities and expose critical resources to unauthorized access or compromise. Common misconfigurations include weak access controls, open network ports, and incorrect permission settings on cloud resources.

Secrets management

Terraform relies on access keys and secret keys to authenticate with cloud providers and provision resources.

Storing these credentials insecurely can lead to security vulnerabilities such as unauthorized access and data breaches.

Handling access credentials securely is crucial to the overall security posture of Terraform deployments.

State security

Terraform uses state files to keep track of the resources it has created or modified.

These state files contain sensitive information, such as resource IDs, metadata, and secrets as referenced above. Inadequate management of state files can lead to security risks, including unauthorized access and data exposure.

State files can be stored either locally on a machine (suitable only for solo testing) or on a remote backend, such as a cloud storage resource, which should be encrypted and locked down.

Supply chain security

As with any software development process, the supply chain of Terraform modules and associated dependencies can introduce security risks.

Organizations must assess the trustworthiness and security of the modules they use and ensure they are regularly updated to address any vulnerabilities.

Permissions management

Appropriate permissions and access controls are essential to prevent unauthorized changes to infrastructure resources.

Managing permissions effectively can help reduce the risk of accidental or malicious actions that could compromise the security of the infrastructure.

Recommendations

To stay secure while using Terraform, users should follow these best practices:

  1. Execute Terraform programmatically to minimize human error and enforce security policies.
  2. Use safe Terraform modules and avoid using untrusted or vulnerable third-party components.
  3. Secure the data store when remotely storing state data to prevent unauthorized access (for example, through encryption and restrictive access permissions).
  4. Avoid storing secrets in state files; instead, use secret management solutions like AWS Secrets Manager, Azure Key Vault, or Google Cloud Secret Manager.
  5. Use Terraform security scanners to identify and remediate potential vulnerabilities.
  6. Implement centralized security policy and governance within Terraform code to improve visibility and enforce least privilege.
  7. Require multi-factor authentication for collaborators to improve security posture.
  8. Keep Terraform and all modules up to date.
  9. Regularly audit terraform configurations for security vulnerabilities and misconfigurations, and build in appropriate automated tooling to detect violations prior to deployment.
  10. Conduct regular drift detection to determine if resources deployed in your cloud provider match what should have been deployed in the terraform state file.

Conclusion

Terraform is a powerful tool for managing cloud infrastructure, but it can introduce security risks if not used properly.

By following Terraform security best practices, users can minimize the risk of security incidents and maintain a secure Terraform environment.

It's essential to keep Terraform configurations and infrastructure up-to-date, monitor for security threats, and adapt to the evolving threat landscape. By doing so, users can ensure that their cloud infrastructure is secure and compliant with industry standards.