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The why, what and how of OIDC for Github Actions

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Introduction

As organizations increasingly adopt cloud-native architectures and continuous integration/continuous deployment (CI/CD) pipelines, securing access to cloud resources becomes paramount. GitHub Actions, a popular CI/CD tool, has integrated OpenID Connect (OIDC) to streamline and secure the authentication process. This post will explore why OIDC is essential, what it entails, and how to implement it for GitHub Actions.

Why OIDC?

Enhanced Security

Traditional methods of managing secrets often involve static credentials, which can be compromised or leaked. OIDC provides a more secure alternative by enabling short-lived, token-based authentication. This reduces the risk associated with long-lived credentials.

Seamless Integration

OIDC allows GitHub Actions to authenticate with cloud providers without manually managing and rotating credentials. This integration simplifies workflows and enhances security by leveraging the identity of the CI/CD environment.

Reduced Complexity

With OIDC, you can eliminate the need for managing secrets in your repository settings. Instead, GitHub Actions can dynamically acquire tokens, reducing the operational burden and potential for errors.

What is OIDC?

OpenID Connect (OIDC) is an authentication layer built on top of OAuth 2.0. It allows applications to verify the identity of users based on authentication performed by an authorization server. In the context of GitHub Actions, OIDC is used to authenticate workflows with cloud providers securely.

Key Components

  • Identity Provider (IdP): This is the service that provides authentication, such as GitHub’s OIDC provider.
  • Token: A short-lived credential issued by the IdP that grants access to cloud resources.
  • Authorization Server: A service that issues tokens and validates their authenticity.

How to Implement OIDC for GitHub Actions

Step 1: Configure Your Cloud Provider

  1. Create a Service Account: In your cloud provider’s console, create a service account or equivalent with the necessary permissions.
  2. Trust Relationship: Configure the trust relationship to allow GitHub’s OIDC provider to assume roles or access resources. This typically involves setting up a policy that includes GitHub’s OIDC issuer URL.

Step 2: Set Up Your GitHub Actions Workflow

  1. Define the Workflow: In your .github/workflows directory, create or update your workflow YAML file.

  2. Add OIDC Authentication: Use the oidc token provided by GitHub Actions. Here’s an example snippet for an AWS integration:

    jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v3
      - name: Configure AWS Credentials
        uses: aws-actions/configure-aws-credentials@v1
        with:
          role-to-assume: arn:aws:iam::123456789012:role/GitHubActionsRole
          aws-region: us-east-1

    This step configures AWS credentials using the OIDC token, assuming the role with the appropriate permissions.

Step 3: Test and Validate

  1. Run the Workflow: Trigger the GitHub Actions workflow and verify that it executes successfully.
  2. Monitor Logs: Check the logs for authentication issues or errors to ensure everything is working as expected.

Conclusion

OIDC in GitHub Actions provides a secure and efficient way to manage authentication with cloud providers. By leveraging short-lived tokens and reducing the complexity of secret management, organizations can enhance their security posture and streamline their CI/CD workflows. Implementing OIDC is a forward-thinking approach to modern CI/CD security, aligning with best practices and simplifying access control.

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