Terraform Where to Store Secrets: Best Practices and Solutions

Estimated reading time: 10 minutes

Last updated on October 25th, 2024 at 02:55 pm

Terraform is used to manage and provision the infrastructure, and keeping the infrastructure secure is critical. This blog “Terraform Where to Store Secrets” will provide various methods for storing secrets, the pros and cons of each, and best practices for keeping your infrastructure secrets safe.

Why Storing Secrets Securely is Important?

Understanding Secrets in Terraform

While provisioning the infrastructure, secrets can be API keys, passwords, tokens, and other sensitive information needed to run resources. These secrets include:

SecretsDescription
API KeysUsed for accessing the external service AWS, Google Cloud, Azure
PasswordAuthentication for Databases, VM, and other resources.
SSH KeysSecure access to the server and other resources.
TLS CertificateEncrypting communication between user to service, service to service.
Configuration DetailsDatabase connection string or private endpoints
Terraform Where to Store Secrets: Types of Secrets

Managing the secrets is important because they grant access to critical systems and sensitive data. Misconfiguration and Mismanagement can expose these secrets and lead to security vulnerabilities.

Risks of Improper Secrets Management

Let’s understand the risks involved in improper secret management and later learn Terraform Where to Store Secrets:

1. Unauthorized Access

If critical secrets are exposed, unauthorized users can gain access to systems, databases, and services, which later can be used to steal data and disrupt the service.

2. Data Breaches

Exposed unauthorized secrets can lead to data breaches. Sensitive data is accessed, stolen, and leaked, which results in financial damage to reputation.

3. Infrastructure Compromised

Unauthorized access to infrastructure can lead to configuration modification, deploying malicious resources, and taking control of the infrastructure.

Industries have strict regulations for data protection. Failure to secure secrets can lead to non-compliance with data protection laws such as GDPR, HIPAA, or PCI-DSS.

5. Operational Downtime

Failure to secure the secrets can cause service disruption and less optional downtime, affecting business and customer trust.

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Common Methods for Storing Secrets in Terraform

To answer the question: “Terraform Where to Store Secrets?”, Terraform provides several methods for storing and imaging the secrets. Let’s check them out one by one and discuss the pros and cons.

Environment Variables

For “Terraform Where to Store Secrets”, you can use the environment variable for a simpler setup but limited security.

How to Store Secrets in Environment Variables?

Storing the secrets in the environment variable is one of the simplest methods.

1. Set the environment variables in your terminal:

Bash
export TF_VAR_db_password="super-secure-db-password"

2. Reference the environment variable in your Terraform configuration:

HCL
variable "db_password" {
  description = "The secure database password"
  type        = string
}

resource "aws_db_instance" "db_instance" {
  engine         = "mysql"
  instance_class = "db.t2.micro"
  username       = "admin"
  password       = var.db_password
}

Advantages & Disadvantages of Environment Variables

Advantages:

  • Easy to implement and integrate.
  • No changes are needed in the Terraform code.

Disadvantages:

  • Variable values can be exposed in logs or process lists.
  • Troublesome for managing a large number of secrets.

Terraform Cloud & Enterprise

Looking at “Terraform Where to Store Secrets”, Terraform Cloud & Enterprise offers built-in secure storage and a seamless way to manage the secrets within the Terraform code.

Same as the environment variable, you don’t need much configuration change, it directly integrates with your existing workflow.

Terraform Cloud & Enterprise use the workspace to manage state files and variables. Secrets are stored securely and later referenced in your Terraform configuration.

Advantages:

  • Out-of-the-box integration with Terraform workflow.
  • Secure storage and management of secrets.

Disadvantages:

  • Paid option, required a subscription
  • Less flexible compared to some third-party tools.

Third-Party Secret Management Tools

“Terraform Where to Store Secrets” highlights third-party tools to store and manage secrets for advanced control.

Terraform Where to Store Secrets Cloud Provider
Terraform Where to Store Secrets: Cloud Provider

Integrating HashiCorp Vault with Terraform

You can easily connect the HashiCorp Vault with Terraform:

1. Store a secret in Vault:

Bash
vault kv put secret/db_password value="super-secure-db-password"

2. Configure the Vault provider in Terraform:

HCL
provider "vault" {
  address = "http://127.0.0.1:8200"
}

data "vault_secret" "db" {
  path = "secret/db_password"
}

resource "aws_db_instance" "example" {
  engine         = "mysql"
  instance_class = "db.t2.micro"
  username       = "admin"
  password       = data.vault_secret.db.data["value"]
}

Integrating AWS Secrets Manager with Terraform

1. Store a secret in AWS Secret Manager:

Bash
aws secretsmanager create-secret --name db_password --secret-string "super-secure-db-password"

2. Reference the secret in Terraform:

HCL
data "aws_secretsmanager_secret" "db" {
  name = "db_password"
}

data "aws_secretsmanager_secret_version" "db_ver" {
  secret_id = data.aws_secretsmanager_secret.db.id
}

resource "aws_db_instance" "example" {
  engine         = "mysql"
  instance_class = "db.t2.micro"
  username       = "admin"
  password       = data.aws_secretsmanager_secret_version.db_ver.secret_string
}

Integrating Azure Key Vault with Terraform

1. Store a secret in the Azure Key Vault

Bash
az keyvault secret set --vault-name "myKeyVault" --name "db-password" --value "super-secure-db-password"

2. Reference the secret in Terraform

HCL
provider "azurerm" {
  features {}
}

data "azurerm_key_vault_secret" "example" {
  name         = "db-password"
  key_vault_id = azurerm_key_vault.example.id
}

resource "azurerm_key_vault" "example" {
  name                = "myKeyVault"
  resource_group_name = "secret-resources"
  location            = "West Europe"
  sku_name            = "standard"
}

resource "azurerm_sql_server" "example" {
  name                         = "sqlserver"
  resource_group_name          = "db-resources"
  location                     = "West Europe"
  version                      = "12.0"
  administrator_login          = "admin"
  administrator_login_password = data.azurerm_key_vault_secret.example.value
}

Integrating Google Cloud Secret Manager with Terraform

1. Store a secret in Google Cloud Secret Manager

Bash
echo -n "super-secure-db-password" | gcloud secrets create db-password --data-file=-

2. Reference the secret in Terraform

HCL
provider "google" {
  project = "my-project"
  region  = "us-central1"
}

data "google_secret_manager_secret_version" "example" {
  secret = "db-password"
}

resource "google_sql_database_instance" "example" {
  name             = "db-instance"
  database_version = "MYSQL_5_7"
  settings {
    tier = "db-f1-micro"
  }
  root_password = data.google_secret_manager_secret_version.example.secret_data
}

Advantages:

  • Robust and highly secure.
  • Feature-rich options like versioning, access control ( ACL ), and audit

Disadvantages:

  • Required the complex setups
  • Paid options required additional cost

Read more on the “Top 5 Terraform Module Versioning Best Practices

Best Practice for Using Third-Part Tools

  • Encrypt the secrets in both ways:
    • Encrypt at rest
    • Encrypt in transit
  • Use the role-based access control known as RBAC to limit access.
  • Follow the least privilege principle when granting permission.
  • Regularly rotate the secrets and Terraform configuration.
  • Regularly audit the log for secret access & permission.

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Terraform Where to Store Secrets: Best Practices

Here are some tips for “Terraform Where to Store Secrets: Best Practices” to manage your infrastructure effectively and securely.

1. Always use Encryption for Storing & Transmitting Secrets:
  • Encrypt at Rest: Most secret management tools offer built-in support for this. Ensure the secrets are encrypted when stored.
  • Encrypted in Transit: Use a secure communication protocol such as HTTPS, or TLS to transmit the secrets to protect from MITM attacks.
2. Limit Access to Secrets using RBAC:
  • Role-Based Access Control: Implement a strict RBAC policy to access the secrets. Ensure only authorized users can access the system and secrets
  • Granular Policy: Define the granular access policies to control who can read/write and manage the secrets.
3. Regular Audit & Rotation:
  • Audit Acess: Regularly audit the access logs to ensure only authorized users have access. Implement and track the access pattern for anomalies.
  • Secret Rotation: Periodically rotate the secrets to protect them from the risk of long-term exposure. Automate the entire secret rotation process.
4. Avoid Hardcoded Secrets:
  • Use Variable: Define and use variables for secrets and avoid hardcoding in code directly.
  • External Management: Store secrets in environment variables or secret management tools.
5. Use Dedicated Secret Management:
  • Third-Party Tools: Use dedicated secret management tools like HarshiCorp Value, AWS Secret Manager, Azure Key Vault, or Google Secert Manager.
  • Integration: External tools provide seamless integration and retrieve the secrets dynamically.
6. Principle of Least Privilege:
  • Minimal Access: Grant only minimum required access to secrets. Ensure the service and user have the necessary permission to perform their tasks.
  • Regular Review: Review the policy and update the access control to ensure the permission is accurate.
7. Terraform Modules for Consistency:
  • Reusable Modules: Create reusable Terraform Modules for the resource that needs secrets. Reusability handles the secrets across the infrastructure.
  • Encapsulation: Separate the secret management logic within the module to reduce the risk exposure.
8. Implement Version Control:
  • Versioning: Use secret management tools that support the versioning. Version control allows you to manage and track changes of secrets over time.
  • Rollback: Quick rollback to the previous secret version in case of an issue.
9. Monitor & Alert on Access:
  • Monitoring: Set up monitoring to track access to secrets and detect unauthorized access.
  • Alert: Configure alerts for anomalies and suspicious access patterns and alert on failed attempts to ensure a quick response to threats.

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Terraform Where to Store Secrets: Common Mistakes

While following the “Terraform Where to Store Secrets: Best Practices”, avoid common mistakes to maintain secure management.

1. Storing Secrets in Plaintext / Version Control:
  • Avoid Plaintext: Avoid storing a secret in plaintext format within your version control. Use encrypted files or secret management tools.
  • Secure Repositories: If you need to use secrets, use encrypted secrets in version control with access control.
2. Sharing the Secrets Over Insecure Channels:
  • Secure Communication: Don’t share secrets through insecure channels like email or unencrypted apps. Use secret-sharing apps.
  • Time-based Sharing: Use the temporary method to share the secret that expires or is revoked.
3. Not Rotating Secrets:
  • Regular Rotation: Automate the process for secret rotation. Not rotating secrets are exposed to long-term exposure.
  • Emergency Rotation: When you detect the breach, be prepared for the emergency rotation.
4. Loose Acess Control:
  • Access Control: Ensure the ACLs are implemented properly and reviewed properly. Avoid broad permission.

Conclusion

Key points
  • Managing the secrets in Terraform is critical for infrastructure security and integrity.
  • Use various methods for storing the secrets:
  • Environment Variable for ease of use.
  • Terraform Cloud for seamless integration.
  • Third-party tools for built-it secure storage & integration.
Terraform Where to Store Secrets: Final Thoughts

Choosing the right tool for the right job depends on your project requirements. The important point is to prioritize the security and ease of management for secure infrastructure.

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Kashyap Merai
Kashyap Merai

Kashyap Merai, a Certified Solution Architect and Public Cloud Specialist with over 7 years in IT. He helped startups in Real Estate, Media Streaming, and On-Demand industries launch successful public cloud projects.

Passionate about Space, Science, and Computers, He also mentors aspiring cloud engineers, shaping the industry's future.

Connect with him on LinkedIn to stay updated on cloud innovations.