| title | shortTitle | intro | versions | type | topics | redirect_from | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
About security hardening with OpenID Connect |
Security hardening with OpenID Connect |
OpenID Connect allows your workflows to exchange short-lived tokens directly from your cloud provider. |
|
tutorial |
|
|
{% data reusables.actions.enterprise-github-hosted-runners %}
{% data variables.product.prodname_actions %} workflows are often designed to access a cloud provider (such as AWS, Azure, GCP, or HashiCorp Vault) in order to deploy software or use the cloud's services. Before the workflow can access these resources, it will supply credentials, such as a password or token, to the cloud provider. These credentials are usually stored as a secret in {% data variables.product.prodname_dotcom %}, and the workflow presents this secret to the cloud provider every time it runs.
However, using hardcoded secrets requires you to create credentials in the cloud provider and then duplicate them in {% data variables.product.prodname_dotcom %} as a secret.
With OpenID Connect (OIDC), you can take a different approach by configuring your workflow to request a short-lived access token directly from the cloud provider. Your cloud provider also needs to support OIDC on their end, and you must configure a trust relationship that controls which workflows are able to request the access tokens. Providers that currently support OIDC include Amazon Web Services, Azure, Google Cloud Platform, and HashiCorp Vault, among others.
By updating your workflows to use OIDC tokens, you can adopt the following good security practices:
- No cloud secrets: You won't need to duplicate your cloud credentials as long-lived {% data variables.product.prodname_dotcom %} secrets. Instead, you can configure the OIDC trust on your cloud provider, and then update your workflows to request a short-lived access token from the cloud provider through OIDC.
- Authentication and authorization management: You have more granular control over how workflows can use credentials, using your cloud provider's authentication (authN) and authorization (authZ) tools to control access to cloud resources.
- Rotating credentials: With OIDC, your cloud provider issues a short-lived access token that is only valid for a single job, and then automatically expires.
The following diagram gives an overview of how {% data variables.product.prodname_dotcom %}'s OIDC provider integrates with your workflows and cloud provider:
- In your cloud provider, create an OIDC trust between your cloud role and your {% data variables.product.prodname_dotcom %} workflow(s) that need access to the cloud.
- Every time your job runs, {% data variables.product.prodname_dotcom %}'s OIDC Provider auto-generates an OIDC token. This token contains multiple claims to establish a security-hardened and verifiable identity about the specific workflow that is trying to authenticate.
- You could include a step or action in your job to request this token from {% data variables.product.prodname_dotcom %}'s OIDC provider, and present it to the cloud provider.
- Once the cloud provider successfully validates the claims presented in the token, it then provides a short-lived cloud access token that is available only for the duration of the job.
When you configure your cloud to trust {% data variables.product.prodname_dotcom %}'s OIDC provider, you must add conditions that filter incoming requests, so that untrusted repositories or workflows can’t request access tokens for your cloud resources:
- Before granting an access token, your cloud provider checks that the
subjectand other claims used to set conditions in its trust settings match those in the request's JSON Web Token (JWT). As a result, you must take care to correctly define the subject and other conditions in your cloud provider. - The OIDC trust configuration steps and the syntax to set conditions for cloud roles (using Subject and other claims) will vary depending on which cloud provider you're using. For some examples, see "Example subject claims."
Each job requests an OIDC token from {% data variables.product.prodname_dotcom %}'s OIDC provider, which responds with an automatically generated JSON web token (JWT) that is unique for each workflow job where it is generated. When the job runs, the OIDC token is presented to the cloud provider. To validate the token, the cloud provider checks if the OIDC token's subject and other claims are a match for the conditions that were preconfigured on the cloud role's OIDC trust definition.
The following example OIDC token uses a subject (sub) that references a job environment named prod in the octo-org/octo-repo repository.
{
"typ": "JWT",
"alg": "RS256",
"x5t": "example-thumbprint",
"kid": "example-key-id"
}
{
"jti": "example-id",
"sub": "repo:octo-org/octo-repo:environment:prod",
"environment": "prod",
"aud": "{% ifversion ghes %}https://HOSTNAME{% else %}https://github.com{% endif %}/octo-org",
"ref": "refs/heads/main",
"sha": "example-sha",
"repository": "octo-org/octo-repo",
"repository_owner": "octo-org",
"actor_id": "12",
"repository_visibility": "private",
"repository_id": "74",
"repository_owner_id": "65",
"run_id": "example-run-id",
"run_number": "10",
"run_attempt": "2",
"runner_environment": "github-hosted"
"actor": "octocat",
"workflow": "example-workflow",
"head_ref": "",
"base_ref": "",
"event_name": "workflow_dispatch",{% ifversion actions-OIDC-custom-claim-enterprise %}
"enterprise": "avocado-corp",{% endif %}{% ifversion actions-OIDC-enterprise_id-claim %}
"enterprise_id": "2",{% endif %}
"ref_type": "branch",
"job_workflow_ref": "octo-org/octo-automation/.github/workflows/oidc.yml@refs/heads/main",
"iss": "{% ifversion ghes %}https://HOSTNAME/_services/token{% else %}https://token.actions.githubusercontent.com{% endif %}",
"nbf": 1632492967,
"exp": 1632493867,
"iat": 1632493567
}To see all the claims supported by {% data variables.product.prodname_dotcom %}'s OIDC provider, review the claims_supported entries at
{% ifversion ghes %}https://HOSTNAME/_services/token/.well-known/openid-configuration{% else %}https://token.actions.githubusercontent.com/.well-known/openid-configuration{% endif %}.
The token includes the standard audience, issuer, and subject claims.
| Claim | Claim type | Description |
|---|---|---|
aud |
Audience | By default, this is the URL of the repository owner, such as the organization that owns the repository. You can set a custom audience with a toolkit command: core.getIDToken(audience) |
iss |
Issuer | The issuer of the OIDC token: {% ifversion ghes %}https://HOSTNAME/_services/token{% else %}https://token.actions.githubusercontent.com{% endif %} |
sub |
Subject | Defines the subject claim that is to be validated by the cloud provider. This setting is essential for making sure that access tokens are only allocated in a predictable way. |
The OIDC token also includes additional standard JOSE header parameters and claims.
| Header Parameter | Parameter type | Description |
|---|---|---|
alg |
Algorithm | The algorithm used by the OIDC provider. |
kid |
Key identifier | Unique key for the OIDC token. |
typ |
Type | Describes the type of token. This is a JSON Web Token (JWT). |
| Claim | Claim type | Description |
|---|---|---|
exp |
Expires at | Identifies the expiry time of the JWT. |
iat |
Issued at | The time when the JWT was issued. |
jti |
JWT token identifier | Unique identifier for the OIDC token. |
nbf |
Not before | JWT is not valid for use before this time. |
The token also includes custom claims provided by {% data variables.product.prodname_dotcom %}.
| Claim | Description |
|---|---|
actor |
The personal account that initiated the workflow run. |
actor_id |
The ID of personal account that initiated the workflow run. |
base_ref |
The target branch of the pull request in a workflow run. |
| {% ifversion actions-OIDC-custom-claim-enterprise %} | |
enterprise |
The name of the enterprise that contains the repository from where the workflow is running. |
| {% endif %} | |
| {% ifversion actions-OIDC-enterprise_id-claim %} | |
enterprise_id |
The ID of the enterprise that contains the repository from where the workflow is running. |
| {% endif %} | |
environment |
The name of the environment used by the job. If the environment claim is included (also via include_claim_keys), an environment is required and must be provided. |
event_name |
The name of the event that triggered the workflow run. |
head_ref |
The source branch of the pull request in a workflow run. |
job_workflow_ref |
For jobs using a reusable workflow, the ref path to the reusable workflow. For more information, see "AUTOTITLE." |
job_workflow_sha |
For jobs using a reusable workflow, the commit SHA for the reusable workflow file. |
ref |
(Reference) The git ref that triggered the workflow run. |
ref_type |
The type of ref, for example: "branch". |
repository_visibility |
The visibility of the repository where the workflow is running. Accepts the following values: internal, private, or public. |
repository |
The repository from where the workflow is running. |
repository_id |
The ID of the repository from where the workflow is running. |
repository_owner |
The name of the organization in which the repository is stored. |
repository_owner_id |
The ID of the organization in which the repository is stored. |
run_id |
The ID of the workflow run that triggered the workflow. |
run_number |
The number of times this workflow has been run. |
run_attempt |
The number of times this workflow run has been retried. |
runner_environment |
The type of runner used by the job. Accepts the following values: github-hosted or self-hosted. |
workflow |
The name of the workflow. |
workflow_ref |
{% data reusables.actions.workflow-ref-description %} |
workflow_sha |
{% data reusables.actions.workflow-sha-description %} |
With OIDC, a {% data variables.product.prodname_actions %} workflow requires a token in order to access resources in your cloud provider. The workflow requests an access token from your cloud provider, which checks the details presented by the JWT. If the trust configuration in the JWT is a match, your cloud provider responds by issuing a temporary token to the workflow, which can then be used to access resources in your cloud provider. You can configure your cloud provider to only respond to requests that originate from a specific organization's repository. You can also specify additional conditions, described below.
Audience and Subject claims are typically used in combination while setting conditions on the cloud role/resources to scope its access to the GitHub workflows.
- Audience: By default, this value uses the URL of the organization or repository owner. This can be used to set a condition that only the workflows in the specific organization can access the cloud role.
- Subject: By default, has a predefined format and is a concatenation of some of the key metadata about the workflow, such as the {% data variables.product.prodname_dotcom %} organization, repository, branch, or associated
jobenvironment. See "Example subject claims" to see how the subject claim is assembled from concatenated metadata.
If you need more granular trust conditions, you can customize the {% ifversion ghec %}issuer (iss) and {% endif %}subject (sub) claim{% ifversion ghec %}s that are{% else %} that's{% endif %} included with the JWT. For more information, see "Customizing the token claims".
There are also many additional claims supported in the OIDC token that can be used for setting these conditions. In addition, your cloud provider could allow you to assign a role to the access tokens, letting you specify even more granular permissions.
{% note %}
Note: To control how your cloud provider issues access tokens, you must define at least one condition, so that untrusted repositories can’t request access tokens for your cloud resources.
{% endnote %}
The following examples demonstrate how to use "Subject" as a condition, and explain how the "Subject" is assembled from concatenated metadata. The subject uses information from the job context, and instructs your cloud provider that access token requests may only be granted for requests from workflows running in specific branches, environments. The following sections describe some common subjects you can use.
The subject claim includes the environment name when the job references an environment.
You can configure a subject that filters for a specific environment name. In this example, the workflow run must have originated from a job that has an environment named Production, in a repository named octo-repo that is owned by the octo-org organization:
- Syntax:
repo:ORG-NAME/REPO-NAME:environment:ENVIRONMENT-NAME - Example:
repo:octo-org/octo-repo:environment:Production
The subject claim includes the pull_request string when the workflow is triggered by a pull request event, but only if the job doesn't reference an environment.
You can configure a subject that filters for the pull_request event. In this example, the workflow run must have been triggered by a pull_request event in a repository named octo-repo that is owned by the octo-org organization:
- Syntax:
repo:ORG-NAME/REPO-NAME:pull_request - Example:
repo:octo-org/octo-repo:pull_request
The subject claim includes the branch name of the workflow, but only if the job doesn't reference an environment, and if the workflow is not triggered by a pull request event.
You can configure a subject that filters for a specific branch name. In this example, the workflow run must have originated from a branch named demo-branch, in a repository named octo-repo that is owned by the octo-org organization:
- Syntax:
repo:ORG-NAME/REPO-NAME:ref:refs/heads/BRANCH-NAME - Example:
repo:octo-org/octo-repo:ref:refs/heads/demo-branch
The subject claim includes the tag name of the workflow, but only if the job doesn't reference an environment, and if the workflow is not triggered by a pull request event.
You can create a subject that filters for specific tag. In this example, the workflow run must have originated with a tag named demo-tag, in a repository named octo-repo that is owned by the octo-org organization:
- Syntax:
repo:ORG-NAME/REPO-NAME:ref:refs/tags/TAG-NAME - Example:
repo:octo-org/octo-repo:ref:refs/tags/demo-tag
To configure the subject in your cloud provider's trust relationship, you must add the subject string to its trust configuration. The following examples demonstrate how various cloud providers can accept the same repo:octo-org/octo-repo:ref:refs/heads/demo-branch subject in different ways:
| Cloud provider | Example |
|---|---|
| Amazon Web Services | "{% ifversion ghes %}HOSTNAME/_services/token{% else %}token.actions.githubusercontent.com{% endif %}:sub": "repo:octo-org/octo-repo:ref:refs/heads/demo-branch" |
| Azure | repo:octo-org/octo-repo:ref:refs/heads/demo-branch |
| Google Cloud Platform | (assertion.sub=='repo:octo-org/octo-repo:ref:refs/heads/demo-branch') |
| HashiCorp Vault | bound_subject="repo:octo-org/octo-repo:ref:refs/heads/demo-branch" |
For more information, see the guides listed in "Enabling OpenID Connect for your cloud provider."
To update your custom actions to authenticate using OIDC, you can use getIDToken() from the Actions toolkit to request a JWT from {% data variables.product.prodname_dotcom %}'s OIDC provider. For more information, see "OIDC Token" in the npm package documentation.
You could also use a curl command to request the JWT, using the following environment variables.
| Variable | Description |
|---|---|
ACTIONS_ID_TOKEN_REQUEST_URL |
The URL for {% data variables.product.prodname_dotcom %}'s OIDC provider. |
ACTIONS_ID_TOKEN_REQUEST_TOKEN |
Bearer token for the request to the OIDC provider. |
For example:
curl -H "Authorization: bearer $ACTIONS_ID_TOKEN_REQUEST_TOKEN" "$ACTIONS_ID_TOKEN_REQUEST_URL&audience=api://AzureADTokenExchange"{% data reusables.actions.oidc-permissions-token %}
You can security harden your OIDC configuration by customizing the claims that are included with the JWT. These customizations allow you to define more granular trust conditions on your cloud roles when allowing your workflows to access resources hosted in the cloud:
- You can customize values for {% ifversion ghec %}
issueror {% endif %}audienceclaims. See {% ifversion ghec %}"Customizing theissuervalue for an enterprise" and {% endif %}"Customizing theaudiencevalue." - You can customize the format of your OIDC configuration by setting conditions on the subject (
sub) claim that require JWT tokens to originate from a specific repository, reusable workflow, or other source. - You can define granular OIDC policies by using additional OIDC token claims, such as
repository_idandrepository_visibility. See "Understanding the OIDC token."
When you use custom actions in your workflows, those actions may use the {% data variables.product.prodname_actions %} Toolkit to enable you to supply a custom value for the audience claim. Some cloud providers also use this in their official login actions to enforce a default value for the audience claim. For example, the GitHub Action for Azure Login provides a default aud value of api://AzureADTokenExchange, or it allows you to set a custom aud value in your workflows. For more information on the {% data variables.product.prodname_actions %} Toolkit, see the OIDC token section in the documentation.
If you do not want to use the default aud value offered by an action, you can provide a custom value for the audience claim. This allows you to set a condition that only workflows in a specific repository or organization can access the cloud role. If the action you are using supports this, you can use the with keyword in your workflow to pass a custom aud value to the action. For more information, see "AUTOTITLE."
{% ifversion ghec %}
By default, the JWT is issued by {% data variables.product.prodname_dotcom %}'s OIDC provider at https://token.actions.githubusercontent.com. This path is presented to your cloud provider using the iss value in the JWT.
To security harden their OIDC configuration, enterprise administrators can configure their enterprise to receive tokens from a unique URL at https://token.actions.githubusercontent.com/<enterpriseSlug>, replacing <enterpriseSlug> with the slug value of the enterprise.
This configuration means that your enterprise will receive the OIDC token from a unique URL, and you can then configure your cloud provider to only accept tokens from that URL. This helps ensure that only the enterprise's repositories can access your cloud resources using OIDC.
To activate this setting for your enterprise, an enterprise administrator must use the /enterprises/{enterprise}/actions/oidc/customization/issuer endpoint and specify "include_enterprise_slug": true in the request body. For more information, see "AUTOTITLE."
After this setting is applied, the JWT will contain the updated iss value. In the following example, the iss key uses octocat-inc as its enterpriseSlug value:
{
"jti": "6f4762ed-0758-4ccb-808d-ee3af5d723a8",
"sub": "repo:octocat-inc/private-server:ref:refs/heads/main",
"aud": "http://octocat-inc.example/octocat-inc",
"enterprise": "octocat-inc",
"enterprise_id": "123",
"iss": "https://token.actions.githubusercontent.com/octocat-inc",
"bf": 1755350653,
"exp": 1755351553,
"iat": 1755351253
}{% endif %}
To help improve security, compliance, and standardization, you can customize the standard claims to suit your required access conditions. If your cloud provider supports conditions on subject claims, you can create a condition that checks whether the sub value matches the path of the reusable workflow, such as "job_workflow_ref:octo-org/octo-automation/.github/workflows/oidc.yml@refs/heads/main". The exact format will vary depending on your cloud provider's OIDC configuration. To configure the matching condition on {% data variables.product.prodname_dotcom %}, you can can use the REST API to require that the sub claim must always include a specific custom claim, such as job_workflow_ref. You can use the REST API to apply a customization template for the OIDC subject claim; for example, you can require that the sub claim within the OIDC token must always include a specific custom claim, such as job_workflow_ref. For more information, see "AUTOTITLE."
{% note %}
Note: When the organization template is applied, it will not affect any workflows already using OIDC unless their repository has opted in to custom organization templates. For all repositories, existing and new, the repository owner will need to use the repository-level REST API to opt in to receive this configuration by setting use_default to false. Alternatively, the repository owner could use the REST API to apply a different configuration specific to the repository. For more information, see "AUTOTITLE."
{% endnote %}
Customizing the claims results in a new format for the entire sub claim, which replaces the default predefined sub format in the token described in "AUTOTITLE."
{% note %}
Note: The sub claim uses the shortened form repo (for example, repo:ORG-NAME/REPO-NAME) instead of repository to reference the repository.
{% endnote %}
The following example templates demonstrate various ways to customize the subject claim. To configure these settings on {% data variables.product.prodname_dotcom %}, admins use the REST API to specify a list of claims that must be included in the subject (sub) claim.
{% data reusables.actions.use-request-body-api %}
To customize your subject claims, you should first create a matching condition in your cloud provider's OIDC configuration, before customizing the configuration using the REST API. Once the configuration is completed, each time a new job runs, the OIDC token generated during that job will follow the new customization template. If the matching condition doesn't exist in the cloud provider's OIDC configuration before the job runs, the generated token might not be accepted by the cloud provider, since the cloud conditions may not be synchronized.
This example template allows the sub claim to have a new format, using repository_owner and repository_visibility:
{
"include_claim_keys": [
"repository_owner",
"repository_visibility"
]
}In your cloud provider's OIDC configuration, configure the sub condition to require that claims must include specific values for repository_owner and repository_visibility. For example: "sub": "repository_owner:monalisa:repository_visibility:private". The approach lets you restrict cloud role access to only private repositories within an organization or enterprise.
This example template enables the sub claim to have a new format with only the value of repository_owner.
{% data reusables.actions.use-request-body-api %}
{
"include_claim_keys": [
"repository_owner"
]
}
In your cloud provider's OIDC configuration, configure the sub condition to require that claims must include a specific value for repository_owner. For example: "sub": "repository_owner:monalisa"
This example template allows the sub claim to have a new format that contains the value of the job_workflow_ref claim. This enables an enterprise to use reusable workflows to enforce consistent deployments across its organizations and repositories.
{% data reusables.actions.use-request-body-api %}
{
"include_claim_keys": [
"job_workflow_ref"
]
}In your cloud provider's OIDC configuration, configure the sub condition to require that claims must include a specific value for job_workflow_ref. For example: "sub": "job_workflow_ref:octo-org/octo-automation/.github/workflows/oidc.yml@refs/heads/main".
The following example template combines the requirement of a specific reusable workflow with additional claims.
{% data reusables.actions.use-request-body-api %}
This example also demonstrates how to use "context" to define your conditions. This is the part that follows the repository in the default sub format. For example, when the job references an environment, the context contains: environment:ENVIRONMENT-NAME.
{
"include_claim_keys": [
"repo",
"context",
"job_workflow_ref"
]
}In your cloud provider's OIDC configuration, configure the sub condition to require that claims must include specific values for repo, context, and job_workflow_ref.
This customization template requires that the sub uses the following format: repo:ORG-NAME/REPO-NAME:environment:ENVIRONMENT-NAME:job_workflow_ref:REUSABLE-WORKFLOW-PATH.
For example: "sub": "repo:octo-org/octo-repo:environment:prod:job_workflow_ref:octo-org/octo-automation/.github/workflows/oidc.yml@refs/heads/main"
This example template lets you grant cloud access to all the workflows in a specific repository, across all branches/tags and environments. {% ifversion ghec %}To further improve security, you can combine this template with a unique issuer URL for your enterprise, as described in "Customizing the issuer value for an enterprise."{% endif %}
{% data reusables.actions.use-request-body-api %}
{
"include_claim_keys": [
"repo"
]
}In your cloud provider's OIDC configuration, configure the sub condition to require a repo claim that matches the required value.
This example template enables predictable OIDC claims with system-generated GUIDs that do not change between renames of entities (such as renaming a repository).
{% data reusables.actions.use-request-body-api %}
{
"include_claim_keys": [
"repository_id"
]
}In your cloud provider's OIDC configuration, configure the sub condition to require a repository_id claim that matches the required value.
or:
{
"include_claim_keys": [
"repository_owner_id"
]
}In your cloud provider's OIDC configuration, configure the sub condition to require a repository_owner_id claim that matches the required value.
This example template resets the subject claims to the default format. This template effectively opts out of any organization-level customization policy.
{% data reusables.actions.use-request-body-api %}
{
"include_claim_keys": [
"repo",
"context"
]
}In your cloud provider's OIDC configuration, configure the sub condition to require that claims must include specific values for repo and context.
All repositories in an organization have the ability to opt in or opt out of (organization and repository-level) customized sub claim templates.
To opt out a repository and reset back to the default sub claim format, a repository administrator must use the REST API endpoint at "AUTOTITLE."
To configure repositories to use the default sub claim format, use the PUT /repos/{owner}/{repo}/actions/oidc/customization/sub REST API endpoint at with the following request body.
{
"use_default": true
}Once an organization has created a customized sub claim template, the REST API can be used to programmatically apply the template to repositories within the organization. A repository administrator can configure their repository to use the template created by the administrator of their organization.
To configure the repository to use the organization's template, a repository admin must use the PUT /repos/{owner}/{repo}/actions/oidc/customization/sub REST API endpoint at with the following request body. For more information, see "AUTOTITLE."
{
"use_default": false
}You can now update your YAML workflows to use OIDC access tokens instead of secrets. Popular cloud providers have published their official login actions that make it easy for you to get started with OIDC. For more information about updating your workflows, see the cloud-specific guides listed below in "Enabling OpenID Connect for your cloud provider."
{% ifversion fpt or ghec %}
You can use a {% data variables.product.prodname_actions %} workflow in a repository as a trusted publisher for a PyPI project. Using a workflow as a trusted publisher allows OIDC access tokens to be exchanged for temporary PyPI API tokens. For more information, see "AUTOTITLE" and "Publishing to PyPI with a Trusted Publisher" in the PyPI documentation.
{% endif %}
To enable and configure OIDC for your specific cloud provider, see the following guides:
To enable and configure OIDC for another cloud provider, see the following guide:
You can use the github/actions-oidc-debugger action to visualize the claims that would be sent, before integrating with a cloud provider. This action requests a JWT and prints the claims included within the JWT that were received from {% data variables.product.prodname_actions %}.