--- layout: docs page_title: AWS - Secrets Engines description: |- The AWS secrets engine for Vault generates access keys dynamically based on IAM policies. --- # AWS secrets engine The AWS secrets engine generates AWS access credentials dynamically based on IAM policies. This generally makes working with AWS IAM easier, since it does not involve clicking in the web UI. Additionally, the process is codified and mapped to internal auth methods (such as LDAP). The AWS IAM credentials are time-based and are automatically revoked when the Vault lease expires. Vault supports three different types of credentials to retrieve from AWS: 1. `iam_user`: Vault will create an IAM user for each lease, attach the managed and inline IAM policies as specified in the role to the user, and if a [permissions boundary](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies_boundaries.html) is specified on the role, the permissions boundary will also be attached. Vault will then generate an access key and secret key for the IAM user and return them to the caller. IAM users have no session tokens and so no session token will be returned. Vault will delete the IAM user upon reaching the TTL expiration. 2. `assumed_role`: Vault will call [sts:AssumeRole](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html) and return the access key, secret key, and session token to the caller. 3. `federation_token`: Vault will call [sts:GetFederationToken](https://docs.aws.amazon.com/STS/latest/APIReference/API_GetFederationToken.html) passing in the supplied AWS policy document and return the access key, secret key, and session token to the caller. 4. `session_token`: Vault will call [sts:GetSessionToken](https://docs.aws.amazon.com/STS/latest/APIReference/API_GetSessionToken.html) and return the access key, secret key, and session token to the caller. ### Static roles The AWS secrets engine supports the concept of "static roles", which are a 1-to-1 mapping of Vault Roles to IAM users. The current password for the user is stored and automatically rotated by Vault on a configurable period of time. This is in contrast to dynamic secrets, where a unique username and password pair are generated with each credential request. When credentials are requested for the Role, Vault returns the current Access Key ID and Secret Access Key for the configured user, allowing anyone with the proper Vault policies to have access to the IAM credentials. Please see the [API documentation](/vault/api-docs/secret/aws#create-static-role) for details on this feature. ## Setup Most secrets engines must be configured in advance before they can perform their functions. These steps are usually completed by an operator or configuration management tool. 1. Enable the AWS secrets engine: ```text $ vault secrets enable aws Success! Enabled the aws secrets engine at: aws/ ``` By default, the secrets engine will mount at the name of the engine. To enable the secrets engine at a different path, use the `-path` argument. 1. Configure the credentials that Vault uses to communicate with AWS to generate the IAM credentials: ```text $ vault write aws/config/root \ access_key=AKIAJWVN5Z4FOFT7NLNA \ secret_key=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 \ region=us-east-1 ``` Internally, Vault will connect to AWS using these credentials. As such, these credentials must be a superset of any policies which might be granted on IAM credentials. Since Vault uses the official AWS SDK, it will use the specified credentials. You can also specify the credentials via the standard AWS environment credentials, shared file credentials, or IAM role/ECS task credentials. (Note that you can't authorize vault with IAM role credentials if you plan on using STS Federation Tokens, since the temporary security credentials associated with the role are not authorized to use GetFederationToken.) In some cases, you cannot set sensitive IAM security credentials in your Vault configuration. For example, your organization may require that all security credentials are short-lived or explicitly tied to a machine identity. To provide IAM security credentials to Vault, we recommend using Vault [plugin workload identity federation](#plugin-workload-identity-federation-wif) (WIF). ~> **Notice:** Even though the path above is `aws/config/root`, do not use your AWS root account credentials. Instead, generate a dedicated user or role. 1. Alternatively, configure the audience claim value and the role ARN to assume for plugin workload identity federation: ```text $ vault write aws/config/root \ identity_token_audience="" \ role_arn="" ``` Vault's identity token provider will internally sign the plugin identity token JWT. Given a trust relationship is configured between Vault and AWS via Web Identity Federation, the secrets engine can exchange this identity token to obtain ephemeral STS credentials. ~> **Notice:** For this trust relationship to be established, AWS must have an an [IAM OIDC identity provider](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_providers_create_oidc.html) configured with information about the fully qualified and network-reachable Issuer URL for Vault's plugin [identity token provider](/vault/api-docs/secret/identity/tokens#read-plugin-identity-well-known-configurations). This is to ensure that AWS can fetch the JWKS [public keys](/vault/api-docs/secret/identity/tokens#read-active-public-keys) and verify the plugin identity token signature. To configure Vault's Issuer, please refer to the Identity Tokens [documentation](/vault/api-docs/secret/identity/tokens#configure-the-identity-tokens-backend) 1. Configure a Vault role that maps to a set of permissions in AWS as well as an AWS credential type. When users generate credentials, they are generated against this role. An example: ```text $ vault write aws/roles/my-role \ credential_type=iam_user \ policy_document=-< ``` Each invocation of the command will generate a new credential. Unfortunately, IAM credentials are eventually consistent with respect to other Amazon services. If you are planning on using these credential in a pipeline, you may need to add a delay of 5-10 seconds (or more) after fetching credentials before they can be used successfully. If you want to be able to use credentials without the wait, consider using the STS method of fetching keys. IAM credentials supported by an STS token are available for use as soon as they are generated. 1. Rotate the credentials that Vault uses to communicate with AWS: ```text $ vault write -f aws/config/rotate-root Key Value --- ----- access_key AKIA3ALIVABCDG5XC8H4 ``` Calls from Vault to AWS may fail immediately after calling `aws/config/rotate-root` until AWS becomes consistent again. Refer to the AWS secrets engine API reference for additional information on rotating IAM credentials. ## IAM permissions policy for Vault The `aws/config/root` credentials need permission to manage dynamic IAM users. Here is an example AWS IAM policy that grants the most commonly required permissions Vault needs: ```json { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "iam:AttachUserPolicy", "iam:CreateAccessKey", "iam:CreateUser", "iam:DeleteAccessKey", "iam:DeleteUser", "iam:DeleteUserPolicy", "iam:DetachUserPolicy", "iam:GetUser", "iam:ListAccessKeys", "iam:ListAttachedUserPolicies", "iam:ListGroupsForUser", "iam:ListUserPolicies", "iam:PutUserPolicy", "iam:AddUserToGroup", "iam:RemoveUserFromGroup", "iam:TagUser" ], "Resource": ["arn:aws:iam::ACCOUNT-ID-WITHOUT-HYPHENS:user/vault-*"] } ] } ``` Vault also supports AWS Permissions Boundaries when creating IAM users. If you wish to enforce that Vault always attaches a permissions boundary to an IAM user, you can use a policy like: ```json { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "iam:CreateAccessKey", "iam:DeleteAccessKey", "iam:DeleteUser", "iam:ListAccessKeys", "iam:ListAttachedUserPolicies", "iam:ListGroupsForUser", "iam:ListUserPolicies", "iam:AddUserToGroup", "iam:RemoveUserFromGroup" ], "Resource": ["arn:aws:iam::ACCOUNT-ID-WITHOUT-HYPHENS:user/vault-*"] }, { "Effect": "Allow", "Action": [ "iam:AttachUserPolicy", "iam:CreateUser", "iam:DeleteUserPolicy", "iam:DetachUserPolicy", "iam:PutUserPolicy" ], "Resource": ["arn:aws:iam::ACCOUNT-ID-WITHOUT-HYPHENS:user/vault-*"], "Condition": { "StringEquals": { "iam:PermissionsBoundary": [ "arn:aws:iam::ACCOUNT-ID-WITHOUT-HYPHENS:policy/PolicyName" ] } } } ] } ``` where the "iam:PermissionsBoundary" condition contains the list of permissions boundary policies that you wish to ensure that Vault uses. This policy will ensure that Vault uses one of the permissions boundaries specified (not all of them). ## Plugin Workload Identity Federation (WIF) The AWS secrets engine supports the Plugin WIF workflow, and has a source of identity called a plugin identity token. The plugin identity token is a JWT that is internally signed by Vault's [plugin identity token issuer](/vault/api-docs/secret/identity/tokens#read-plugin-workload-identity-issuer-s-openid-configuration). If there is a trust relationship configured between Vault and AWS through [Web Identity Federation](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_providers_oidc.html), the secrets engine can exchange its identity token for short-lived STS credentials needed to perform its actions. Exchanging identity tokens for STS credentials lets the AWS secrets engine operate without configuring explicit access to sensitive IAM security credentials. To configure the secrets engine to use plugin WIF: 1. Ensure that Vault [openid-configuration](/vault/api-docs/secret/identity/tokens#read-plugin-identity-token-issuer-s-openid-configuration) and [public JWKS](/vault/api-docs/secret/identity/tokens#read-plugin-identity-token-issuer-s-public-jwks) APIs are network-reachable by AWS. We recommend using an API proxy or gateway if you need to limit Vault API exposure. 1. Create an [IAM OIDC identity provider](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_providers_create_oidc.html) in AWS. 1. The provider URL **must** point at your [Vault plugin identity token issuer](/vault/api-docs/secret/identity/tokens#read-plugin-workload-identity-issuer-s-openid-configuration) with the `/.well-known/openid-configuration` suffix removed. For example: `https://host:port/v1/identity/oidc/plugins`. 1. The audience should uniquely identify the recipient of the plugin identity token. In AWS, the recipient is the identity provider. We recommend using the `host:port/v1/identity/oidc/plugins` portion of the provider URL as your recipient since it will be unique for each configured identity provider. 1. Create a [web identity role](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_create_for-idp_oidc.html#idp_oidc_Create) in AWS with the same audience used for your IAM OIDC identity provider. 1. Configure the AWS secrets engine with the IAM OIDC audience value and web identity role ARN. ```shell-session $ vault write aws/config/root \ identity_token_audience="vault.example/v1/identity/oidc/plugins" \ role_arn="arn:aws:iam::123456789123:role/example-web-identity-role" ``` Your secrets engine can now use plugin WIF for its configuration credentials. By default, WIF [credentials](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRoleWithWebIdentity.html) have a time-to-live of 1 hour and automatically refresh when they expire. Please see the [API documentation](/vault/api-docs/secret/aws#configure-root-credentials) for more details on the fields associated with plugin WIF. ## STS credentials The above demonstrated usage with `iam_user` credential types. As mentioned, Vault also supports `assumed_role`, `federation_token`, and `session_token` credential types. ### STS federation tokens ~> **Notice:** Due to limitations in AWS, in order to use the `federation_token` credential type, Vault **must** be configured with IAM user credentials. AWS does not allow temporary credentials (such as those from an IAM instance profile) to be used. An STS federation token inherits a set of permissions that are the combination (intersection) of four sets of permissions: 1. The permissions granted to the `aws/config/root` credentials 2. The user inline policy configured in the Vault role 3. The managed policy ARNs configured in the Vault role 4. An implicit deny policy on IAM or STS operations. Roles with a `credential_type` of `federation_token` can specify one or more of the `policy_document`, `policy_arns`, and `iam_groups` parameters in the Vault role. The `aws/config/root` credentials require IAM permissions for `sts:GetFederationToken` and the permissions to delegate to the STS federation token. For example, this policy on the `aws/config/root` credentials would allow creation of an STS federated token with delegated `ec2:*` permissions (or any subset of `ec2:*` permissions): ```javascript { "Version": "2012-10-17", "Statement": { "Effect": "Allow", "Action": [ "ec2:*", "sts:GetFederationToken" ], "Resource": "*" } } ``` An `ec2_admin` role would then assign an inline policy with the same `ec2:*` permissions. ```shell-session $ vault write aws/roles/ec2_admin \ credential_type=federation_token \ policy_document=@policy.json ``` The policy.json file would contain an inline policy with similar permissions, less the `sts:GetFederationToken` permission. (We could grant `sts:GetFederationToken` permissions, but STS attaches attach an implicit deny that overrides the allow.) ```javascript { "Version": "2012-10-17", "Statement": { "Effect": "Allow", "Action": "ec2:*", "Resource": "*" } } ``` To generate a new set of STS federation token credentials, we simply write to the role using the aws/sts endpoint: ```shell-session $ vault write aws/sts/ec2_admin ttl=60m Key Value lease_id aws/sts/ec2_admin/31d771a6-fb39-f46b-fdc5-945109106422 lease_duration 60m0s lease_renewable false access_key ASIAJYYYY2AA5K4WIXXX secret_key HSs0DYYYYYY9W81DXtI0K7X84H+OVZXK5BXXXX session_token AQoDYXdzEEwasAKwQyZUtZaCjVNDiXXXXXXXXgUgBBVUUbSyujLjsw6jYzboOQ89vUVIehUw/9MreAifXFmfdbjTr3g6zc0me9M+dB95DyhetFItX5QThw0lEsVQWSiIeIotGmg7mjT1//e7CJc4LpxbW707loFX1TYD1ilNnblEsIBKGlRNXZ+QJdguY4VkzXxv2urxIH0Sl14xtqsRPboV7eYruSEZlAuP3FLmqFbmA0AFPCT37cLf/vUHinSbvw49C4c9WQLH7CeFPhDub7/rub/QU/lCjjJ43IqIRo9jYgcEvvdRkQSt70zO8moGCc7pFvmL7XGhISegQpEzudErTE/PdhjlGpAKGR3d5qKrHpPYK/k480wk1Ai/t1dTa/8/3jUYTUeIkaJpNBnupQt7qoaXXXXXXXXXX ``` ### STS Session Tokens The `session_token` credential type is used to generate short-lived credentials under the root config. To create these with Vault and AWS, you must configure Vault to use IAM user credentials. AWS does not allow temporary credentials, like those from an IAM instance profile, to be used when generating session tokens. STS session tokens inherit any and all permissions granted to the user configured in `aws/config/root`. In this expample, the `temp_user` role will obtain a policy with the same `ec2:*` permissions as the root config. For this reason, assigning a role or policy is disallowed for this credential type. ```shell-session $ vault write aws/roles/temp_user \ credential_type=session_token ``` To generate a new set of STS federation token credentials, write to the `temp_user` role using the `aws/creds` endpoint: ```shell-session $ vault read aws/sts/temp_user ttl=60m Key Value lease_id aws/creds/temp_user/w4eKbMaJOi1xLqG3MWk7y8n6 lease_duration 60m0s lease_renewable false access_key ASIAJYYYY2AA5K4WIXXX secret_key HSs0DYYYYYY9W81DXtI0K7X84H+OVZXK5BXXXX session_token AQoDYXdzEEwasAKwQyZUtZaCjVNDiXXXXXXXXgUgBBVUUbSyujLjsw6jYzboOQ89vUVIehUw/9MreAifXFmfdbjTr3g6zc0me9M+dB95DyhetFItX5QThw0lEsVQWSiIeIotGmg7mjT1//e7CJc4LpxbW707loFX1TYD1ilNnblEsIBKGlRNXZ+QJdguY4VkzXxv2urxIH0Sl14xtqsRPboV7eYruSEZlAuP3FLmqFbmA0AFPCT37cLf/vUHinSbvw49C4c9WQLH7CeFPhDub7/rub/QU/lCjjJ43IqIRo9jYgcEvvdRkQSt70zO8moGCc7pFvmL7XGhISegQpEzudErTE/PdhjlGpAKGR3d5qKrHpPYK/k480wk1Ai/t1dTa/8/3jUYTUeIkaJpNBnupQt7qoaXXXXXXXXXX ``` Session tokens may also require an MFA-based TOTP to be provided if the IAM user is configured to require it. If so, the Vault role requires the MFA device serial number to be set, and the TOTP may be provided when reading credentials from the Vault role. ```shell-session $ vault write aws/roles/mfa_user \ credential_type=session_token \ mfa_serial_number="arn:aws:iam::ACCOUNT-ID-WITHOUT-HYPHENS:mfa/device-name" ``` ```shell-session $ vault read aws/creds/mfa_user mfa_code=123456 ``` ### STS AssumeRole The `assumed_role` credential type is typically used for cross-account authentication or single sign-on (SSO) scenarios. In order to use an `assumed_role` credential type, you must configure outside of Vault: 1. An IAM role 2. IAM inline policies and/or managed policies attached to the IAM role 3. IAM trust policy attached to the IAM role to grant privileges for Vault to assume the role `assumed_role` credentials offer a few benefits over `federation_token`: 1. Assumed roles can invoke IAM and STS operations, if granted by the role's IAM policies. 2. Assumed roles support cross-account authentication 3. Temporary credentials (such as those granted by running Vault on an EC2 instance in an IAM instance profile) can retrieve `assumed_role` credentials (but cannot retrieve `federation_token` credentials). The `aws/config/root` credentials must be allowed `sts:AssumeRole` through one of two methods: 1. The credentials have an IAM policy attached to them against the target role: ```javascript { "Version": "2012-10-17", "Statement": { "Effect": "Allow", "Action": "sts:AssumeRole", "Resource": "arn:aws:iam::ACCOUNT-ID-WITHOUT-HYPHENS:role/RoleNameToAssume" } } ``` 1. A trust policy is attached to the target IAM role for the principal: ```javascript { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "AWS": "arn:aws:iam::ACCOUNT-ID-WITHOUT-HYPHENS:user/VAULT-AWS-ROOT-CONFIG-USER-NAME" }, "Action": "sts:AssumeRole" } ] } ``` When specifying a Vault role with a `credential_type` of `assumed_role`, you can specify more than one IAM role ARN. If you do so, Vault clients can select which role ARN they would like to assume when retrieving credentials from that role. Further, you can specify both a `policy_document` and `policy_arns` parameters; if specified, each acts as a filter on the IAM permissions granted to the assumed role. If `iam_groups` is specified, the inline and attached policies for each IAM group will be added to the `policy_document` and `policy_arns` parameters, respectively, when calling [sts:AssumeRole]. For an action to be allowed, it must be permitted by both the IAM policy on the AWS role that is assumed, the `policy_document` specified on the Vault role (if specified), and the managed policies specified by the `policy_arns` parameter. (The `policy_document` parameter is passed in as the `Policy` parameter to the [sts:AssumeRole] API call, while the `policy_arns` parameter is passed in as the `PolicyArns` parameter to the same call.) Note: When multiple `role_arns` are specified, clients requesting credentials can specify any of the role ARNs that are defined on the Vault role in order to retrieve credentials. However, when `policy_document`, `policy_arns`, or `iam_groups` are specified, that will apply to ALL role credentials retrieved from AWS. Let's create a "deploy" policy using the arn of our role to assume: ```shell-session $ vault write aws/roles/deploy \ role_arns=arn:aws:iam::ACCOUNT-ID-WITHOUT-HYPHENS:role/RoleNameToAssume \ credential_type=assumed_role ``` To generate a new set of STS assumed role credentials, we again write to the role using the aws/sts endpoint: ```shell-session $ vault write aws/sts/deploy ttl=60m Key Value lease_id aws/sts/deploy/31d771a6-fb39-f46b-fdc5-945109106422 lease_duration 60m0s lease_renewable false access_key ASIAJYYYY2AA5K4WIXXX secret_key HSs0DYYYYYY9W81DXtI0K7X84H+OVZXK5BXXXX session_token AQoDYXdzEEwasAKwQyZUtZaCjVNDiXXXXXXXXgUgBBVUUbSyujLjsw6jYzboOQ89vUVIehUw/9MreAifXFmfdbjTr3g6zc0me9M+dB95DyhetFItX5QThw0lEsVQWSiIeIotGmg7mjT1//e7CJc4LpxbW707loFX1TYD1ilNnblEsIBKGlRNXZ+QJdguY4VkzXxv2urxIH0Sl14xtqsRPboV7eYruSEZlAuP3FLmqFbmA0AFPCT37cLf/vUHinSbvw49C4c9WQLH7CeFPhDub7/rub/QU/lCjjJ43IqIRo9jYgcEvvdRkQSt70zO8moGCc7pFvmL7XGhISegQpEzudErTE/PdhjlGpAKGR3d5qKrHpPYK/k480wk1Ai/t1dTa/8/3jUYTUeIkaJpNBnupQt7qoaXXXXXXXXXX ``` [sts:assumerole]: https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html ## Troubleshooting ### Dynamic IAM user errors If you get an error message similar to either of the following, the root credentials that you wrote to `aws/config/root` have insufficient privilege: ```shell-session $ vault read aws/creds/deploy * Error creating IAM user: User: arn:aws:iam::000000000000:user/hashicorp is not authorized to perform: iam:CreateUser on resource: arn:aws:iam::000000000000:user/vault-root-1432735386-4059 $ vault revoke aws/creds/deploy/774cfb27-c22d-6e78-0077-254879d1af3c Revoke error: Error making API request. URL: POST http://127.0.0.1:8200/v1/sys/revoke/aws/creds/deploy/774cfb27-c22d-6e78-0077-254879d1af3c Code: 400. Errors: * invalid request ``` If you get stuck at any time, simply run `vault path-help aws` or with a subpath for interactive help output. ### STS federated token errors Vault generates STS tokens using the IAM credentials passed to `aws/config`. Those credentials must have two properties: - They must have permissions to call `sts:GetFederationToken`. - The capabilities of those credentials have to be at least as permissive as those requested by policies attached to the STS creds. If either of those conditions are not met, a "403 not-authorized" error will be returned. See http://docs.aws.amazon.com/STS/latest/APIReference/API_GetFederationToken.html for more details. Vault 0.5.1 or later is recommended when using STS tokens to avoid validation errors for exceeding the AWS limit of 32 characters on STS token names. The AWS character limit for token names **includes** the full path to the token. For example, `aws/sts/dev005_vault-test_testtest` (34 characters) exceeds the limit , but `aws/roles/dev005_vaulttest-test` (31 characters) does not. ### AWS instance metadata timeouts @include 'aws-imds-timeout.mdx' ## API The AWS secrets engine has a full HTTP API. Please see the [AWS secrets engine API](/vault/api-docs/secret/aws) for more details.