Secrets in Terraform

In the current situation of cloud computing and infrastructure as code (IaC), the efficient management and security of resources have assumed paramount importance.

Terraform, an open-source IaC tool, enjoys widespread adoption among DevOps teams for provisioning and administering cloud infrastructure.

While terraform is renowned for its robustness, flexibility, and user-friendliness, it also presents challenges in the environment of safeguarding sensitive data, such as API keys, passwords, and other confidential information.

Effective secrets management stands as a cornerstone in preserving the security and reliability of your infrastructure.

Inadequate treatment of secrets can have dire consequences, including unauthorized access, data breaches, and the risk of regulatory non-compliance.

This blog endeavors to furnish an exhaustive guide on secrets management within Terraform.

It seeks to impart valuable insights into best practices, tools, and methodologies, all aimed at fortifying your infrastructure and ensuring the security of your secrets.

The objective of this blog post is to offer an all-encompassing guide on secrets management in Terraform, providing valuable insights into best practices, tools, and methodologies.

The ultimate goal is to empower you with the knowledge needed to fortify your infrastructure and maintain the security of your confidential information.

Important things to remember when managing the secrets of Terraform

Before moving into the intricacies of secrets management in Terraform, it’s crucial to establish a strong foundation. The following prerequisites will enable you to fully leverage this guide:

1. Basic understanding of Terraform

It is essential to have a fundamental grasp of Terraform and its key concepts, including providers, resources, and modules.

2. Installed Terraform

To actively engage with this guide and experiment with the illustrative examples, it is imperative to have Terraform successfully installed on your local machine.

3. Access to a cloud provider account

Access to an account with a cloud provider, like AWS, Azure, or Google Cloud Platform, is essential to apply the concepts and tactics elucidated in this guide.

4. Familiarity with basic security concepts

A foundational comprehension of fundamental security principles is advantageous. This includes knowledge about encryption, access control, and authentication.

If needed, you can refer to an introductory resource on Identity and Access Management for a better understanding.

Understanding secrets management

Secrets encompass sensitive information like API keys, passwords, access tokens, and encryption keys.

Properly controlling access to these secrets is essential for preserving the security and integrity of your infrastructure.

Effective secrets management is vital to prevent unauthorized access and mitigate potential security threats.

What are the types of secrets in Terraform?

In the Terraform context, secrets can be categorized into various types, including:

• API keys for authentication with cloud providers and other services.

• Database credentials such as usernames and passwords.

• SSH keys for secure server access.

What are the risks of inadequate secrets management?

Inadequate secrets management poses several potential risks, which include:

1. Compliance Violations

Many industries are bound by stringent regulations governing the handling of sensitive data. Inadequate secrets management can result in substantial fines and damage to reputation.

2. Unauthorized access

Poorly managed secrets may grant unauthorized individuals access to sensitive resources, leading to data breaches and potential security infringements.

3. Security breaches

Exposed secrets can be exploited by malicious actors to steal, manipulate data, or compromise entire systems.

Recognizing these risks underscores the significance of implementing robust secrets management practices within your Terraform deployments.

Best practices for securely managing secrets in Terraform

Effective secrets management in Terraform is paramount to safeguard sensitive information and thwart unauthorized access.

In this section, we’ll delve into several best practices for secrets handling in Terraform, including employing environment variables, utilizing secure external storage, and encrypting confidential data.

Utilize Environment Variables By storing secrets as environment variables, you can keep them separate from your Terraform code and version control systems.

Terraform provides straightforward access to environment variables using the var keyword. For instance, to configure an AWS provider with an API key stored as an environment variable:

variable "aws_access_key" {}

provider "aws" {
  access_key = var.aws_access_key
  region     = "us-east-2"
}

To set the environment variable, use the export command in your terminal:

export TF_VAR_aws_access_key=<your_access_key>

Store Secrets in a Secure external storage rather than storing secrets directly within your Terraform code or environment variables, it’s advisable to leverage a secure external storage service explicitly designed for secrets management.

Services like HashiCorp Vault or AWS Secrets Manager offer advanced capabilities, including access control, auditing, and automated secrets rotation.

Subsequent sections will explore the integration of Terraform with Vault and AWS secrets manager in more depth.

Encrypt Sensitive Data When storing secrets in remote backends or transmitting them across networks, it is imperative to ensure encryption. Many cloud providers provide Key Management Services (KMS) for data encryption and decryption. For instance, with AWS KMS, you can encrypt sensitive data utilizing the aws_kms_secrets data source:

data "aws_kms_secrets" "mysecret" {
  secret {
    name    = "db_username"
    payload = "encrypted_db_username_here"
  }

  secret {
    name    = "db_password"
    payload = "encrypted_db_password_here"
  }
}

resource "aws_db_instance" "mysecret" {
  username = data.aws_kms_secrets.mysecret.plaintext["db_username"]
  password = data.aws_kms_secrets.mysecret.plaintext["db_password"]
}

Leveraging secrets management tools

Secret management tools play a crucial role in enhancing the security of your Terraform deployments, providing a centralized and secure repository for sensitive information.

In this section, we will explore various secret management tools and provide detailed instructions on how to integrate them with Terraform.

There exists a variety of secrets management tools, each offering distinct features and degrees of integration with Terraform. Some notable options include:

• HashiCorp Vault

  A comprehensive secrets management solution capable of handling a wide range of secret types, tightly integrated with Terraform. AWS Secrets Manager:

• AWS secrets manager

  A managed service provided by AWS, designed for seamless integration with other AWS services and terraform.

Integrating Terraform with Vault

HashiCorp Vault is a widely adopted secrets management solution that enables secure storage, management, and retrieval of secrets. To integrate Terraform with Vault, you can follow these steps:

1. Install and configure Vault

Refer to the official Vault documentation to install and configure Vault either on your local machine or a dedicated server.

2. Enable the Kv Secrets engine in Vault

Use the following command to enable the key-value (KV) secrets engine, allowing you to store key-value pairs:

vault secrets enable -path=mysecrets kv

3. Write secrets to Vault

To store your secrets in Vault, you can use the following command:

vault kv put my-secrets/aws aws_access_key_id=<your_access_key> aws_secret_access_key=<your_secret_key>

Replace and with the actual AWS access key and secret access key values you want to store in Vault. This command stores these key-value pairs under the "my-secrets/aws" path within your Vault instance.

To configure the Terraform Vault provider, you need to set up the provider and authenticate it using a token or other supported authentication method in your Terraform configuration.

provider "vault" {
  address = "https://vault.example.com:8200"
  token   = "<your_vault_token>"
}

To access secrets from Vault in Terraform, you can use the vault_generic_secret data source to retrieve secret values. Here’s how you can do it:

data "vault_generic_secret" "aws_credentials" {
  path = "mysecrets/aws"
}

provider "aws" {
  access_key = data.vault_generic_secret.aws_credentials.data["aws_access_key_id"]
  secret_key = data.vault_generic_secret.aws_credentials.data["aws_secret_access_key"]
  region     = "us-east-2"
}

Implementing Role-based Access Control (RBAC) in Terraform

Role-Based Access Control (RBAC) is an effective approach to managing access to sensitive information in your Terraform deployments, allowing you to grant permissions based on roles and responsibilities.

In this section, we will discuss the fundamentals of RBAC and provide guidance on configuring RBAC in Terraform.

Understanding RBAC

RBAC is a security model that assigns permissions to users based on their roles within an organization instead of assigning permissions directly to individual users.

This approach simplifies access management and improves security by ensuring that users only have the permissions they need to perform their job functions. The main components of RBAC are:

• Roles: Collections of permissions that define what actions users can perform on specific resources.

• Users: Individuals or entities that interact with the system and are assigned roles based on their responsibilities.

• Permissions: Access rights that determine what actions can be performed on specific resources. As you guessed, implementing RBAC in Terraform involves defining roles, assigning them to users, and managing permissions for accessing sensitive data, such as secrets.

Integrating Terraform with AWS secrets manager

Integrating terraform with AWS secrets manager is a secure way to manage sensitive data.

Follow these steps to achieve the integration:

1. Store secrets in AWS secrets manager

Start by logging into the AWS Management Console. Navigate to AWS Secrets Manager and create a new secret that will contain your sensitive data, such as API keys and database credentials.

2. Configure the Terraform AWS provider

In your Terraform configuration, set up the AWS provider with the appropriate credentials.

You can use the secrets stored in AWS Secrets Manager to securely authenticate your Terraform resources. Here’s an example of how to set up the AWS provider:

provider "aws" {
  region = "us-east-2"
}

To access secrets stored in AWS Secrets Manager within your Terraform configuration, you can utilize the aws_secretsmanager_secret_version data source. Here’s how you can do it:

data "aws_secretsmanager_secret_version" "sample" {
  secret_id = "arn:aws:secretsmanager:us-east-2:246801357924:secret:sample-24680"
}

locals {
  sample_secret = jsondecode(data.aws_secretsmanager_secret_version.sample.secret_string)
}

You can utilize the local.sample_secret variable to access the stored secret as a JSON object. For instance, if your secret includes a database username and password, you can reference them as follows:

resource "aws_db_instance" "mysecret" {
  # ...
  username = local.sample_secret["db_username"]
  password = local.sample_secret["db_password"]
}

3. Create policies in Vault

Establish Vault policies specifying the permissions for each role. For instance, you can generate a policy that permits read access to a specific path within Vault:

path "secret/data/my-app/*" {
  capabilities = ["read"]
}

4. Define roles in Vault

Create roles in Vault and associate them with the corresponding policies. These roles determine which permissions users have based on their assigned role. For example, you can create a role that uses the “my-app-reader” policy:

path "auth/approle/role/my-app-role" {
  policies = ["my-app-reader"]
}

5. Configure Terraform to authenticate with Vault

In your Terraform configuration, set up the Vault provider and specify the role_id and secret_id to authenticate:

provider "vault" {
  address = "https://vault.example.com:8200"
  auth_login {
    path = "auth/approle/login"
    parameters = {
      role_id   = "my-app-role-id"
      secret_id = "my-app-secret-id"
    }
  }
}

6. Access secrets in Terraform

Utilize the Vault provider in your Terraform configuration to access secrets based on the policies and roles configured in Vault.

This ensures that users in Terraform can only access secrets based on their assigned roles and permissions. For instance:

data "vault_generic_secret" "my_app_secrets" {
  path = "secret/data/my-app/secrets"
}

By following these steps, you can implement RBAC in Terraform using HashiCorp Vault, granting permissions to users based on their assigned roles and ensuring secure access to sensitive data.

7. Assign policies to users

After creating the necessary policies, you can assign them to users by associating the policies with specific authentication methods or individual users:

vault write auth/userpass/users/alice password="alicespassword" policies="read-only"

8. Access secrets in Terraform based on RBAC

Users can now access secrets in Terraform according to the policies assigned to them.

For instance, a user with the “read-only” policy can retrieve secrets from the “my-secrets” path within Terraform:

data "vault_generic_secret" "my_secrets" {
  path = "secret/data/my-secrets"
}

By following these steps, users can securely access secrets in Terraform based on their assigned policies, ensuring proper Role-Based Access Control (RBAC) in your infrastructure management.

Summing up

In conclusion, secrets management in Terraform is a vital component of safeguarding the security and reliability of your infrastructure deployments.

Adhering to best practices such as using environment variables, securely storing secrets in external repositories, and implementing Role-Based Access Control (RBAC) can significantly reduce the risks associated with sensitive data handling.

Furthermore, the utilization of secret management tools like HashiCorp Vault and AWS Secrets Manager offers advanced features that can further enhance your security posture.

Continuous monitoring and auditing are crucial for maintaining a secure environment.

By embracing these practices and tools, you can establish a robust secrets management strategy in Terraform, safeguarding your sensitive data and upholding the security of your infrastructure deployments.

Written by

Manieendar Mohan

Cyber Security Lead Engineer

Contributor

Neda Ali

Product Marketing Specialist