open-vault/website/source/docs/auth/aws.html.md

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docs	Auth Backend: AWS	docs-auth-aws	The aws backend allows automated authentication of AWS entities.

Auth Backend: aws

The aws auth backend provides an automated mechanism to retrieve a Vault token for AWS EC2 instances and IAM principals. Unlike most Vault authentication backends, this backend does not require manual first-deploying, or provisioning security-sensitive credentials (tokens, username/password, client certificates, etc), by operators under many circumstances. It treats AWS as a Trusted Third Party and uses either the cryptographically signed dynamic metadata information that uniquely represents each EC2 instance or a special AWS request signed with AWS IAM credentials. The metadata information is automatically supplied by AWS to all EC2 instances, and IAM credentials are automatically supplied to AWS instances in IAM instance profiles, Lambda functions, and others, and it is this information already provided by AWS which Vault can use to authenticate clients.

Authentication Workflow

There are two authentication types present in the aws backend: ec2 and iam. Based on how you attempt to authenticate, Vault will determine if you are attempting to use the ec2 or iam type. Each has a different authentication workflow, and each can solve different use cases. See the section on comparing the two auth methods below to help determine which method is more appropriate for your use cases.

EC2 Authentication Method

EC2 instances have access to metadata describing the instance. (For those not familiar with instance metadata, details can be found here.)

One piece of "dynamic metadata" available to the EC2 instance, is the instance identity document, a JSON representation of a collection of instance metadata. AWS also provides PKCS#7 signature of the instance metadata document, and publishes the public keys (grouped by region) which can be used to verify the signature. Details on the instance identity document and the signature can be found here.

During login, the backend verifies the signature on the PKCS#7 document, ensuring that the information contained within, is certified accurate by AWS. Before succeeding the login attempt and returning a Vault token, the backend verifies the current running status of the instance via the EC2 API.

There are various modifications to this workflow that provide more or less security, as detailed later in this documentation.

IAM Authentication Method

The AWS STS API includes a method, sts:GetCallerIdentity, which allows you to validate the identity of a client. The client signs a GetCallerIdentity query using the AWS Signature v4 algorithm and submits 4 pieces of information to the Vault server to recreate a valid signed request: the request URL, the request body, the request headers, and the request method, as the AWS signature is computed over those fields. The Vault server then reconstructs the query and forwards it on to the AWS STS service and validates the result back. Clients don't need network-level access to talk to the AWS STS API endpoint; they merely need access to the credentials to sign the request. However, it means that the Vault server does need network-level access to send requests to the STS endpoint.

Importantly, the credentials used to sign the GetCallerIdentity request can come from the EC2 instance metadata service for an EC2 instance, or from the AWS environment variables in an AWS Lambda function execution, which obviates the need for an operator to manually provision some sort of identity material first. However, the credentials can, in principle, come from anywhere, not just from the locations AWS has provided for you.

Each signed AWS request includes the current timestamp to mitigate the risk of replay attacks. In addition, Vault allows you to require an additional header, X-Vault-AWS-IAM-Server-ID, to be present to mitigate against different types of replay attacks (such as a signed GetCallerIdentity request stolen from a dev Vault instance and used to authenticate to a prod Vault instance). Vault further requires that this header be one of the headers included in the AWS signature and relies upon AWS to authenticate that signature.

While AWS API endpoints support both signed GET and POST requests, for simplicity, the aws backend supports only POST requests. It also does not support presigned requests, i.e., requests with X-Amz-Credential, X-Amz-signature, and X-Amz-SignedHeaders GET query parameters containing the authenticating information.

It's also important to note that Amazon does NOT appear to include any sort of authorization around calls to GetCallerIdentity. For example, if you have an IAM policy on your credential that requires all access to be MFA authenticated, non-MFA authenticated credentials (i.e., raw credentials, not those retrieved by calling GetSessionToken and supplying an MFA code) will still be able to authenticate to Vault using this backend. It does not appear possible to enforce an IAM principal to be MFA authenticated while authenticating to Vault.

Authorization Workflow

The basic mechanism of operation is per-role. Roles are registered in the backend and associated with a specific authentication type that cannot be changed once the role has been created. Roles can also be associated with various optional restrictions, such as the set of allowed policies and max TTLs on the generated tokens. Each role can be specified with the constraints that are to be met during the login. For example, one such constraint that is supported is to bind against AMI ID. A role which is bound to a specific AMI, can only be used for login by EC2 instances that are deployed on the same AMI.

In general, role bindings that are specific to an EC2 instance are only checked when the ec2 auth method is used to login, while bindings specific to IAM principals are only checked when the iam auth method is used to login. However, the iam method includes the ability for you to "infer" an EC2 instance ID from the authenticated client and apply many of the bindings that would otherwise only apply specifically to EC2 instances.

In many cases, an organization will use a "seed AMI" that is specialized after bootup by configuration management or similar processes. For this reason, a role entry in the backend can also be associated with a "role tag" when using the ec2 auth type. These tags are generated by the backend and are placed as the value of a tag with the given key on the EC2 instance. The role tag can be used to further restrict the parameters set on the role, but cannot be used to grant additional privileges. If a role with an AMI bind constraint has "role tag" enabled on the role, and the EC2 instance performing login does not have an expected tag on it, or if the tag on the instance is deleted for some reason, authentication fails.

The role tags can be generated at will by an operator with appropriate API access. They are HMAC-signed by a per-role key stored within the backend, allowing the backend to verify the authenticity of a found role tag and ensure that it has not been tampered with. There is also a mechanism to blacklist role tags if one has been found to be distributed outside of its intended set of machines.

IAM Authentication Inferences

With the iam auth method, normally Vault will see the IAM principal that authenticated, either the IAM user or role. However, when you have an EC2 instance in an IAM instance profile, Vault can actually see the instance ID of the instance and can "infer" that it's an EC2 instance. However, there are important security caveats to be aware of before configuring Vault to make that inference.

Each AWS IAM role has a "trust policy" which specifies which entities are trusted to call sts:AssumeRole on the role and retrieve credentials that can be used to authenticate with that role. When AssumeRole is called, a parameter called RoleSessionName is passed in, which is chosen arbitrarily by the entity which calls AssumeRole. If you have a role with an ARN arn:aws:iam::123456789012:role/MyRole, then the credentials returned by calling AssumeRole on that role will be arn:aws:sts::123456789012:assumed-role/MyRole/RoleSessionName where RoleSessionName is the session name in the AssumeRole API call. It is this latter value which Vault actually sees.

When you have an EC2 instance in an instance profile, the corresponding role's trust policy specifies that the principal "Service": "ec2.amazonaws.com" is trusted to call AssumeRole. When this is configured, EC2 calls AssumeRole on behalf of your instance, with a RoleSessionName corresponding to the instance's instance ID. Thus, it is possible for Vault to extract the instance ID out of the value it sees when an EC2 instance in an instance profile authenticates to Vault with the iam authentication method. This is known as "inferencing." Vault can be configured, on a role-by-role basis, to infer that a caller is an EC2 instance and, if so, apply further bindings that apply specifically to EC2 instances -- most of the bindings available to the ec2 authentication backend.

However, it is very important to note that if any entity other than an AWS service is permitted to call AssumeRole on your role, then that entity can simply pass in your instance's instance ID and spoof your instance to Vault. This also means that anybody who is able to modify your role's trust policy (e.g., via iam:UpdateAssumeRolePolicy, then that person could also spoof your instances. If this is a concern but you would like to take advantage of inferencing, then you should tightly restrict who is able to call AssumeRole on the role, tightly restrict who is able to call UpdateAssumeRolePolicy on the role, and monitor CloudTrail logs for calls to AssumeRole and UpdateAssumeRolePolicy. All of these caveats apply equally to using the iam authentication method without inferencing; the point is merely that Vault cannot offer an iron-clad guarantee about the inference and it is up to operators to determine, based on their own AWS controls and use cases, whether or not it's appropriate to configure inferencing.

Mixing Authentication Types

Vault allows you to configure using either the ec2 auth method or the iam auth method, but not both auth methods. Further, Vault will prevent you from enforcing restrictions that it cannot enforce given the chosen auth type for a role. Some examples of how this works in practice:

1. You configure a role with the ec2 auth type, with a bound AMI ID. A client would not be able to login using the iam auth type.
2. You configure a role with the iam auth type, with a bound IAM principal ARN. A client would not be able to login with the ec2 auth method.
3. You configure a role with the iam auth type and further configure inferencing. You have a bound AMI ID and a bound IAM principal ARN. A client must login using the iam method; the RoleSessionName must be a valid instance ID viewable by Vault, and the instance must have come from the bound AMI ID.

Comparison of the EC2 and IAM Methods

The iam and ec2 authentication methods serve similar and somewhat overlapping functionality, in that both authenticate some type of AWS entity to Vault. To help you determine which method is more appropriate for your use case, here is a comparison of the two authentication methods.

• What type of entity is authenticated:
  • The ec2 auth method authenticates only AWS EC2 instances and is specialized to handle EC2 instances, such as restricting access to EC2 instances from a particular AMI, EC2 instances in a particular instance profile, or EC2 instances with a specialized tag value (via the role_tag feature).
  • The iam auth method authenticates generic AWS IAM principals. This can include IAM users, IAM roles assumed from other accounts, AWS Lambdas that are launched in an IAM role, or even EC2 instances that are launched in an IAM instance profile. However, because it authenticates more generalized IAM principals, this backend doesn't offer more granular controls beyond binding to a given IAM principal without the use of inferencing.
• How the entities are authenticated
  • The ec2 auth method authenticates instances by making use of the EC2 instance identity document, which is a cryptographically signed document containing metadata about the instance. This document changes relatively infrequently, so Vault adds a number of other constructs to mitigate against replay attacks, such as client nonces, role tags, instance migrations, etc. Because the instance identity document is signed by AWS, you have a strong guarantee that it came from an EC2 instance.
  • The iam auth method authenticates by having clients provide a specially signed AWS API request which the backend then passes on to AWS to validate the signature and tell Vault who created it. The actual secret (i.e., the AWS secret access key) is never transmitted over the wire, and the AWS signature algorithm automatically expires requests after 15 minutes, providing simple and robust protection against replay attacks. The use of inferencing, however, provides a weaker guarantee that the credentials came from an EC2 instance in an IAM instance profile compared to the ec2 authentication mechanism.
  • The instance identity document used in the ec2 auth method is more likely to be stolen given its relatively static nature, but it's harder to spoof. On the other hand, the credentials of an EC2 instance in an IAM instance profile are less likely to be stolen given their dynamic and short-lived nature, but it's easier to spoof credentials that might have come from an EC2 instance.
• Specific use cases
  • If you have non-EC2 instance entities, such as IAM users, Lambdas in IAM roles, or developer laptops using AdRoll's Hologram then you would need to use the iam auth method.
  • If you have EC2 instances, then you could use either auth method. If you need more granular filtering beyond just the instance profile of given EC2 instances (such as filtering based off the AMI the instance was launched from), then you would need to use the ec2 auth method, change the instance profile associated with your EC2 instances so they have unique IAM roles for each different Vault role you would want them to authenticate to, or make use of inferencing. If you need to make use of role tags, then you will need to use the ec2 auth method.

Client Nonce

Note: this only applies to the ec2 authentication method.

If an unintended party gains access to the PKCS#7 signature of the identity document (which by default is available to every process and user that gains access to an EC2 instance), it can impersonate that instance and fetch a Vault token. The backend addresses this problem by using a Trust On First Use (TOFU) mechanism that allows the first client to present the PKCS#7 signature of the document to be authenticated and denying the rest. An important property of this design is detection of unauthorized access: if an unintended party authenticates, the intended client will be unable to authenticate and can raise an alert for investigation.

During the first login, the backend stores the instance ID that authenticated in a whitelist. One method of operation of the backend is to disallow any authentication attempt for an instance ID contained in the whitelist, using the disallow_reauthentication option on the role, meaning that an instance is allowed to login only once. However, this has consequences for token rotation, as it means that once a token has expired, subsequent authentication attempts would fail. By default, reauthentication is enabled in this backend, and can be turned off using disallow_reauthentication parameter on the registered role.

In the default method of operation, the backend will return a unique nonce during the first authentication attempt, as part of auth metadata. Clients should present this nonce for subsequent login attempts and it should match the nonce cached at the identity-whitelist entry at the backend. Since only the original client knows the nonce, only the original client is allowed to reauthenticate. (This is the reason that this is a whitelist rather than a blacklist; by default, it's keeping track of clients allowed to reauthenticate, rather than those that are not.). Clients can choose to provide a nonce even for the first login attempt, in which case the provided nonce will be tied to the cached identity-whitelist entry. It is recommended to use a strong nonce value in this case.

It is up to the client to behave correctly with respect to the nonce; if the client stores the nonce on disk it can survive reboots, but could also give access to other users or applications on the instance. It is also up to the operator to ensure that client nonces are in fact unique; sharing nonces allows a compromise of the nonce value to enable an attacker that gains access to any EC2 instance to imitate the legitimate client on that instance. This is why nonces can be disabled on the backend side in favor of only a single authentication per instance; in some cases, such as when using ASGs, instances are immutable and single-boot anyways, and in conjunction with a high max TTL, reauthentication may not be needed (and if it is, the instance can simply be shut down and allow ASG to start a new one).

In both cases, entries can be removed from the whitelist by instance ID, allowing reauthentication by a client if the nonce is lost (or not used) and an operator approves the process.

One other point: if available by the OS/distribution being used with the EC2 instance, it is not a bad idea to firewall access to the signed PKCS#7 metadata to ensure that it is accessible only to the matching user(s) that require access.

Advanced Options and Caveats

Dynamic Management of Policies Via Role Tags

Note: This only applies to the ec2 auth method or the iam auth method when inferencing is used.

If the instance is required to have customized set of policies based on the role it plays, the role_tag option can be used to provide a tag to set on instances, for a given role. When this option is set, during login, along with verification of PKCS#7 signature and instance health, the backend will query for the value of a specific tag with the configured key that is attached to the instance. The tag holds information that represents a subset of privileges that are set on the role and are used to further restrict the set of the role's privileges for that particular instance.

A role_tag can be created using auth/aws/role/<role>/tag endpoint and is immutable. The information present in the tag is SHA256 hashed and HMAC protected. The per-role key to HMAC is only maintained in the backend. This prevents an adversarial operator from modifying the tag when setting it on the EC2 instance in order to escalate privileges.

When 'role_tag' option is enabled on a role, the instances are required to have a role tag. If the tag is not found on the EC2 instance, authentication will fail. This is to ensure that privileges of an instance are never escalated for not having the tag on it or for getting the tag removed. If the role tag creation does not specify the policy component, the client will inherit the allowed policies set on the role. If the role tag creation specifies the policy component but it contains no policies, the token will contain only the default policy; by default, this policy allows only manipulation (revocation, renewal, lookup) of the existing token, plus access to its cubbyhole. This can be useful to allow instances access to a secure "scratch space" for storing data (via the token's cubbyhole) but without granting any access to other resources provided by or resident in Vault.

Handling Lost Client Nonces

Note: This only applies to the ec2 auth method.

If an EC2 instance loses its client nonce (due to a reboot, a stop/start of the client, etc.), subsequent login attempts will not succeed. If the client nonce is lost, normally the only option is to delete the entry corresponding to the instance ID from the identity whitelist in the backend. This can be done via the auth/aws/identity-whitelist/<instance_id> endpoint. This allows a new client nonce to be accepted by the backend during the next login request.

Under certain circumstances there is another useful setting. When the instance is placed onto a host upon creation, it is given a pendingTime value in the instance identity document (documentation from AWS does not cover this option, unfortunately). If an instance is stopped and started, the pendingTime value is updated (this does not apply to reboots, however).

The backend can take advantage of this via the allow_instance_migration option, which is set per-role. When this option is enabled, if the client nonce does not match the saved nonce, the pendingTime value in the instance identity document will be checked; if it is newer than the stored pendingTime value, the backend assumes that the client was stopped/started and allows the client to log in successfully, storing the new nonce as the valid nonce for that client. This essentially re-starts the TOFU mechanism any time the instance is stopped and started, so should be used with caution. Just like with initial authentication, the legitimate client should have a way to alert (or an alert should trigger based on its logs) if it is denied authentication.

Unfortunately, the allow_instance_migration only helps during stop/start actions; the current metadata does not provide for a way to allow this automatic behavior during reboots. The backend will be updated if this needed metadata becomes available.

The allow_instance_migration option is set per-role, and can also be specified in a role tag. Since role tags can only restrict behavior, if the option is set to false on the role, a value of true in the role tag takes effect; however, if the option is set to true on the role, a value set in the role tag has no effect.

Disabling Reauthentication

Note: this only applies to the ec2 authentication method.

If in a given organization's architecture, a client fetches a long-lived Vault token and has no need to rotate the token, all future logins for that instance ID can be disabled. If the option disallow_reauthentication is set, only one login will be allowed per instance. If the intended client successfully retrieves a token during login, it can be sure that its token will not be hijacked by another entity.

When disallow_reauthentication option is enabled, the client can choose not to supply a nonce during login, although it is not an error to do so (the nonce is simply ignored). Note that reauthentication is enabled by default. If only a single login is desired, disallow_reauthentication should be set explicitly on the role or on the role tag.

The disallow_reauthentication option is set per-role, and can also be specified in a role tag. Since role tags can only restrict behavior, if the option is set to false on the role, a value of true in the role tag takes effect; however, if the option is set to true on the role, a value set in the role tag has no effect.

Blacklisting Role Tags

Note: this only applies to the ec2 authentication method or the iam auth method when inferencing is used.

Role tags are tied to a specific role, but the backend has no control over, which instances using that role, should have any particular role tag; that is purely up to the operator. Although role tags are only restrictive (a tag cannot escalate privileges above what is set on its role), if a role tag is found to have been used incorrectly, and the administrator wants to ensure that the role tag has no further effect, the role tag can be placed on a blacklist via the endpoint auth/aws/roletag-blacklist/<role_tag>. Note that this will not invalidate the tokens that were already issued; this only blocks any further login requests from those instances that have the blacklisted tag attached to them.

Expiration Times and Tidying of blacklist and whitelist Entries

The expired entries in both identity whitelist and role tag blacklist are deleted automatically. The entries in both of these lists contain an expiration time which is dynamically determined by three factors: max_ttl set on the role, max_ttl set on the role tag, and max_ttl value of the backend mount. The least of these three dictates the maximum TTL of the issued token, and correspondingly will be set as the expiration times of these entries.

The endpoints aws/auth/tidy/identity-whitelist and aws/auth/tidy/roletag-blacklist are provided to clean up the entries present in these lists. These endpoints allow defining a safety buffer, such that an entry must not only be expired, but be past expiration by the amount of time dictated by the safety buffer in order to actually remove the entry.

Automatic deletion of expired entries is performed by the periodic function of the backend. This function does the tidying of both blacklist role tags and whitelist identities. Periodic tidying is activated by default and will have a safety buffer of 72 hours, meaning only those entries are deleted which were expired before 72 hours from when the tidy operation is being performed. This can be configured via config/tidy/roletag-blacklist and config/tidy/identity-whitelist endpoints.

Varying Public Certificates

Note: this only applies to the ec2 authentication method.

The AWS public certificate, which contains the public key used to verify the PKCS#7 signature, varies for different AWS regions. The primary AWS public certificate, which covers most AWS regions, is already included in Vault and does not need to be added. Instances whose PKCS#7 signatures cannot be verified by the default public certificate included in Vault can register a different public certificate which can be found [here] (http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-identity-documents.html), via the auth/aws/config/certificate/<cert_name> endpoint.

Dangling Tokens

An EC2 instance, after authenticating itself with the backend, gets a Vault token. After that, if the instance terminates or goes down for any reason, the backend will not be aware of such events. The token issued will still be valid, until it expires. The token will likely be expired sooner than its lifetime when the instance fails to renew the token on time.

Cross Account Access

To allow Vault to authenticate EC2 instances running in other accounts, AWS STS (Security Token Service) can be used to retrieve temporary credentials by assuming an IAM Role in those accounts. All these accounts should be configured at the backend using the auth/aws-ec2/config/sts/<account_id> endpoint.

The account in which Vault is running (i.e. the master account) must be listed as a trusted entity in the IAM Role being assumed on the remote account. The Role itself must allow the ec2:DescribeInstances action, and iam:GetInstanceProfile if IAM Role binding is used (see below).

Furthermore, in the master account, Vault must be granted the action sts:AssumeRole for the IAM Role to be assumed.

Authentication

Via the CLI

Enable AWS EC2 authentication in Vault.

$ vault auth-enable aws

Configure the credentials required to make AWS API calls

If not specified, Vault will attempt to use standard environment variables (AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY) or IAM EC2 instance role credentials if available.

The IAM account or role to which the credentials map must allow the ec2:DescribeInstances action. In addition, if IAM Role binding is used (see bound_iam_role_arn below), iam:GetInstanceProfile must also be allowed.

$ vault write auth/aws/config/client secret_key=vCtSM8ZUEQ3mOFVlYPBQkf2sO6F/W7a5TVzrl3Oj access_key=VKIAJBRHKH6EVTTNXDHA

Configure the policies on the role.

$ vault write auth/aws/role/dev-role auth_type=ec2 bound_ami_id=ami-fce3c696 policies=prod,dev max_ttl=500h

$ vault write auth/aws/role/dev-role-iam auth_type=iam \
              bound_iam_principal_arn=arn:aws:iam::123456789012:role/MyRole policies=prod,dev max_ttl=500h

Configure a required X-Vault-AWS-IAM-Server-ID Header (recommended)

$ vault write auth/aws/config/client iam_server_id_header_value=vault.example.com

Perform the login operation

$ vault write auth/aws/login role=dev-role \
pkcs7=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 nonce=5defbf9e-a8f9-3063-bdfc-54b7a42a1f95

For the iam auth method, generating the signed request is a non-standard operation. The Vault cli supports generating this for you:

$ vault auth -method=aws header_value=vault.example.com role=dev-role-iam

This assumes you have AWS credentials configured in the standard locations AWS SDKs search for credentials (environment variables, ~/.aws/credentials, IAM instance profile in that order). If you do not have IAM credentials available at any of these locations, you can explicitly pass them in on the command line (though this is not recommended), omitting aws_security_token if not applicable .

$ vault auth -method=aws header_value=vault.example.com role=dev-role-iam \
        aws_access_key_id=<access_key> \
        aws_secret_access_key=<secret_key> \
        aws_security_token=<security_token>

An example of how to generate the required request values for the login method can be found found in the vault cli source code. Using an approach such as this, the request parameters can be generated and passed to the login method:

$ vault write auth/aws/login role=dev-role-iam \
        iam_http_request_method=POST \
        iam_request_url=aHR0cHM6Ly9zdHMuYW1hem9uYXdzLmNvbS8= \
        iam_request_body=QWN0aW9uPUdldENhbGxlcklkZW50aXR5JlZlcnNpb249MjAxMS0wNi0xNQ== \
        iam_request_headers=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

Via the API

Enable AWS authentication in Vault.

curl -X POST -H "x-vault-token:123" "http://127.0.0.1:8200/v1/sys/auth/aws" -d '{"type":"aws"}'

Configure the credentials required to make AWS API calls.

curl -X POST -H "x-vault-token:123" "http://127.0.0.1:8200/v1/auth/aws/config/client" -d '{"access_key":"VKIAJBRHKH6EVTTNXDHA", "secret_key":"vCtSM8ZUEQ3mOFVlYPBQkf2sO6F/W7a5TVzrl3Oj"}'

Configure the policies on the role.

curl -X POST -H "x-vault-token:123" "http://127.0.0.1:8200/v1/auth/aws/role/dev-role -d '{"bound_ami_id":"ami-fce3c696","policies":"prod,dev","max_ttl":"500h"}'

curl -X POST -H "x-vault-token:123" "http://127.0.0.1:8200/v1/auth/aws/role/dev-role-iam -d '{"auth_type":"iam","policies":"prod,dev","max_ttl":"500h","bound_iam_principal_arn":"arn:aws:iam::123456789012:role/MyRole"}'

Perform the login operation

curl -X POST "http://127.0.0.1:8200/v1/auth/aws/login" -d '{"role":"dev-role","pkcs7":"'$(curl -s http://169.254.169.254/latest/dynamic/instance-identity/pkcs7 | tr -d '\n')'","nonce":"5defbf9e-a8f9-3063-bdfc-54b7a42a1f95"}'

curl -X POST "http://127.0.0.1:8200/v1/auth/aws/login" -d '{"role":"dev", "iam_http_request_method": "POST", "iam_request_url": "aHR0cHM6Ly9zdHMuYW1hem9uYXdzLmNvbS8=", "iam_request_body": "QWN0aW9uPUdldENhbGxlcklkZW50aXR5JlZlcnNpb249MjAxMS0wNi0xNQ==", "iam_request_headers": "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" }'

The response will be in JSON. For example:

{
  "auth": {
    "renewable": true,
    "lease_duration": 72000,
    "metadata": {
      "role_tag_max_ttl": "0s",
      "role": "ami-f083709d",
      "region": "us-east-1",
      "nonce": "5defbf9e-a8f9-3063-bdfc-54b7a42a1f95",
      "instance_id": "i-a832f734",
      "ami_id": "ami-f083709d"
    },
    "policies": [
      "default",
      "dev",
      "prod"
    ],
    "accessor": "5cd96cd1-58b7-2904-5519-75ddf957ec06",
    "client_token": "150fc858-2402-49c9-56a5-f4b57f2c8ff1"
  },
  "warnings": null,
  "wrap_info": null,
  "data": null,
  "lease_duration": 0,
  "renewable": false,
  "lease_id": "",
  "request_id": "d7d50c06-56b8-37f4-606c-ccdc87a1ee4c"
}

API

/auth/aws/config/client

POST

Description

Configures the credentials required to perform API calls to AWS as well as custom endpoints to talk to AWS APIs. The instance identity document fetched from the PKCS#7 signature will provide the EC2 instance ID. The credentials configured using this endpoint will be used to query the status of the instances via DescribeInstances API. If static credentials are not provided using this endpoint, then the credentials will be retrieved from the environment variables `AWS_ACCESS_KEY`, `AWS_SECRET_KEY` and `AWS_REGION` respectively. If the credentials are still not found and if the backend is configured on an EC2 instance with metadata querying capabilities, the credentials are fetched automatically.

Method

POST

URL

`/auth/aws/config/client`

Parameters

• access_key optional AWS Access key with permissions to query AWS APIs. The permissions required depend on the specific configurations. If using the `iam` auth method without inferencing, then no credentials are necessary. If using the `ec2` auth method or using the `iam` auth method with inferencing, then these credentials need access to `ec2:DescribeInstances`. If additionally a `bound_iam_role` is specified, then these credentials also need access to `iam:GetInstanceProfile`. If, however, an alterate sts configuration is set for the target account, then the credentials must be permissioned to call `sts:AssumeRole` on the configured role, and that role must have the permissions described here.

• secret_key optional AWS Secret key with permissions to query AWS APIs.

• endpoint optional URL to override the default generated endpoint for making AWS EC2 API calls.

• iam_endpoint optional URL to override the default generated endpoint for making AWS IAM API calls.

• sts_endpoint optional URL to override the default generated endpoint for making AWS STS API calls.

• iam_server_id_header_value optional The value to require in the `X-Vault-AWS-IAM-Server-ID` header as part of GetCallerIdentity requests that are used in the iam auth method. If not set, then no value is required or validated. If set, clients must include an X-Vault-AWS-IAM-Server-ID header in the headers of login requests, and further this header must be among the signed headers validated by AWS. This is to protect against different types of replay attacks, for example a signed request sent to a dev server being resent to a production server. Consider setting this to the Vault server's DNS name.

Returns

`204` response code.

GET

Description

Returns the previously configured AWS access credentials.

Method

GET

URL

`/auth/aws/config/client`

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "secret_key": "vCtSM8ZUEQ3mOFVlYPBQkf2sO6F/W7a5TVzrl3Oj",
    "access_key": "VKIAJBRHKH6EVTTNXDHA"
    "endpoint" "",
    "iam_endpoint" "",
    "sts_endpoint" "",
    "iam_server_id_header_value" "",
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

DELETE

Description

Deletes the previously configured AWS access credentials.

Method

DELETE

URL

`/auth/aws/config/client`

Parameters

None.

Returns

`204` response code.

/auth/aws/config/certificate/<cert_name>

POST

Description

Registers an AWS public key to be used to verify the instance identity documents. While the PKCS#7 signature of the identity documents have DSA digest, the identity signature will have RSA digest, and hence the public keys for each type varies respectively. Indicate the type of the public key using the "type" parameter.

Method

POST

URL

`/auth/aws/config/certificate/`

Parameters

• cert_name required Name of the certificate.

• aws_public_cert required AWS Public key required to verify PKCS7 signature of the EC2 instance metadata.

• type optional Takes the value of either "pkcs7" or "identity", indicating the type of document which can be verified using the given certificate. The PKCS#7 document will have a DSA digest and the identity signature will have an RSA signature, and accordingly the public certificates to verify those also vary. Defaults to "pkcs7".

Returns

`204` response code.

GET

Description

Returns the previously configured AWS public key.

Method

GET

URL

`/auth/aws/config/certificate/`

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "aws_public_cert": "-----BEGIN CERTIFICATE-----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\n7HX32MxXYruse9ACFBNGmdX2ZBrVNGrN9N2f6ROk0k9K\n-----END CERTIFICATE-----\n"
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

LIST

Description

Lists all the AWS public certificates that are registered with the backend.

Method

LIST/GET

URL

`/auth/aws/config/certificates` (LIST) or `/auth/aws/config/certificates?list=true` (GET)

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "keys": [
      "cert1"
    ]
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

/auth/aws/config/sts/<account_id>

POST

Description

Allows the explicit association of STS roles to satellite AWS accounts (i.e. those which are not the account in which the Vault server is running.) Login attempts from EC2 instances running in these accounts will be verified using credentials obtained by assumption of these STS roles.

Method

POST

URL

`/auth/aws/config/sts/`

Parameters

• account_id required AWS account ID to be associated with STS role. If set, Vault will use assumed credentials to verify any login attempts from EC2 instances in this account.

• sts_role required AWS ARN for STS role to be assumed when interacting with the account specified. The Vault server must have permissions to assume this role.

Returns

`204` response code.

GET

Description

Returns the previously configured STS role.

Method

GET

URL

`/auth/aws/config/sts/`

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "sts_role ": "arn:aws:iam:<account_id>:role/myRole"
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

LIST

Description

Lists all the AWS Account IDs for which an STS role is registered

Method

LIST/GET

URL

`/auth/aws/config/sts` (LIST) or `/auth/aws/config/sts?list=true` (GET)

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "keys": [
      "<account_id_1>",
      "<account_id_2>"
    ]
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

DELETE

Description

Deletes a previously configured AWS account/STS role association

Method

DELETE

URL

`/auth/aws/config/sts/`

Parameters

None.

Returns

`204` response code.

/auth/aws/config/tidy/identity-whitelist

POST

Description

Configures the periodic tidying operation of the whitelisted identity entries.

Method

POST

URL

`/auth/aws/config/tidy/identity-whitelist`

Parameters

• safety_buffer optional The amount of extra time that must have passed beyond the `roletag` expiration, before it is removed from the backend storage. Defaults to 72h.

• disable_periodic_tidy optional If set to 'true', disables the periodic tidying of the 'identity-whitelist/' entries.

Returns

`204` response code.

GET

Description

Returns the previously configured periodic whitelist tidying settings.

Method

GET

URL

`/auth/aws/config/tidy/identity-whitelist`

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "safety_buffer": 60,
    "disable_periodic_tidy": false
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

DELETE

Description

Deletes the previously configured periodic whitelist tidying settings.

Method

DELETE

URL

`/auth/aws/config/tidy/identity-whitelist`

Parameters

None.

Returns

`204` response code.

/auth/aws/config/tidy/roletag-blacklist

POST

Description

Configures the periodic tidying operation of the blacklisted role tag entries.

Method

POST

URL

`/auth/aws/config/tidy/roletag-blacklist`

Parameters

• safety_buffer optional The amount of extra time that must have passed beyond the `roletag` expiration, before it is removed from the backend storage. Defaults to 72h.

• disable_periodic_tidy optional If set to 'true', disables the periodic tidying of the 'roletag-blacklist/' entries.

Returns

`204` response code.

GET

Description

Returns the previously configured periodic blacklist tidying settings.

Method

GET

URL

`/auth/aws/config/tidy/roletag-blacklist`

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "safety_buffer": 60,
    "disable_periodic_tidy": false
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

DELETE

Description

Deletes the previously configured periodic blacklist tidying settings.

Method

DELETE

URL

`/auth/aws/config/tidy/roletag-blacklist`

Parameters

None.

Returns

`204` response code.

/auth/aws/role/[role]

POST

Description

Registers a role in the backend. Only those instances or principals which are using the role registered using this endpoint, will be able to perform the login operation. Contraints can be specified on the role, that are applied on the instances or principals attempting to login. At least one constraint should be specified on the role. The available constraints you can choose are dependent on the `auth_type` of the role and, if the `auth_type` is `iam`, then whether inferencing is enabled. A role will not let you configure a constraint if it is not checked by the `auth_type` and inferencing configuration of that role.

Method

POST

URL

`/auth/aws/role/`

Parameters

• role required Name of the role.

• auth_type optional The auth type permitted for this role. Valid choices are "ec2" or "iam". If no value is specified, then it will default to "iam" (except for legacy `aws-ec2` auth types, for which it will default to "ec2"). Only those bindings applicable to the auth type chosen will be allowed to be configured on the role.

• bound_ami_id optional If set, defines a constraint on the EC2 instances that they should be using the AMI ID specified by this parameter. This constraint is checked during ec2 auth as well as the iam auth method only when inferring an EC2 instance.

• bound_account_id optional If set, defines a constraint on the EC2 instances that the account ID in its identity document to match the one specified by this parameter. This constraint is checked during ec2 auth as well as the iam auth method only when inferring an EC2 instance.

• bound_region optional If set, defines a constraint on the EC2 instances that the region in its identity document must match the one specified by this parameter. This constraint is only checked by the ec2 auth method as well as the iam auth method only when inferring an ec2 instance..

• bound_vpc_id optional If set, defines a constraint on the EC2 instance to be associated with the VPC ID that matches the value specified by this parameter. This constraint is only checked by the ec2 auth method as well as the iam auth method only when inferring an ec2 instance.

• bound_subnet_id optional If set, defines a constraint on the EC2 instance to be associated with the subnet ID that matches the value specified by this parameter. This constraint is only checked by the ec2 auth method as well as the iam auth method only when inferring an ec2 instance.

• bound_iam_role_arn optional If set, defines a constraint on the authenticating EC2 instance that it must match the IAM role ARN specified by this parameter. The value is prefix-matched (as though it were a glob ending in `*`). The configured IAM user or EC2 instance role must be allowed to execute the `iam:GetInstanceProfile` action if this is specified. This constraint is checked by the ec2 auth method as well as the iam auth method only when inferring an EC2 instance.

• bound_iam_instance_profile_arn optional If set, defines a constraint on the EC2 instances to be associated with an IAM instance profile ARN which has a prefix that matches the value specified by this parameter. The value is prefix-matched (as though it were a glob ending in `*`). This constraint is checked by the ec2 auth method as well as the iam auth method only when inferring an ec2 instance.

• role_tag optional If set, enables the role tags for this role. The value set for this field should be the 'key' of the tag on the EC2 instance. The 'value' of the tag should be generated using `role//tag` endpoint. Defaults to an empty string, meaning that role tags are disabled. This constraint is valid only with the ec2 auth method and is not allowed when an auth_type is iam.

• bound_iam_principal_arn optional Defines the IAM principal that must be authenticated using the iam auth method. It should look like "arn:aws:iam::123456789012:user/MyUserName" or "arn:aws:iam::123456789012:role/MyRoleName". This constraint is only checked by the iam auth method.

• inferred_entity_type optional When set, instructs Vault to turn on inferencing. The only current valid value is "ec2_instance" instructing Vault to infer that the role comes from an EC2 instance in an IAM instance profile. This only applies to the iam auth method. If you set this on an existing role where it had not previously been set, tokens that had been created prior will not be renewable; clients will need to get a new token.

• inferred_aws_region optional When role inferencing is activated, the region to search for the inferred entities (e.g., EC2 instances). Required if role inferencing is activated. This only applies to the iam auth method.

• resolve_aws_unique_ids optional When set, resolves the `bound_iam_principal_arn` to the [AWS Unique ID](http://docs.aws.amazon.com/IAM/latest/UserGuide/reference_identifiers.html#identifiers-unique-ids). This requires Vault to be able to call `iam:GetUser` or `iam:GetRole` on the `bound_iam_principal_arn` that is being bound. Resolving to internal AWS IDs more closely mimics the behavior of AWS services in that if an IAM user or role is deleted and a new one is recreated with the same name, those new users or roles won't get access to roles in Vault that were permissioned to the prior principals of the same name. The default value for new roles is true, while the default value for roles that existed prior to this option existing is false (you can check the value for a given role using the GET method on the role). Any authentication tokens created prior to this being supported won't verify the unique ID upon token renewal. When this is changed from false to true on an existing role, Vault will attempt to resolve the role's bound IAM ARN to the unique ID and, if unable to do so, will fail to enable this option. Changing this from `true` to `false` is not supported; if absolutely necessary, you would need to delete the role and recreate it explicitly setting it to `false`. However; the instances in which you would want to do this should be rare. If the role creation (or upgrading to use this) succeed, then Vault has already been able to resolve internal IDs, and it doesn't need any further IAM permissions to authenticate users. If a role has been deleted and recreated, and Vault has cached the old unique ID, you should just call this endpoint specifying the same `bound_iam_principal_arn` and, as long as Vault still has the necessary IAM permissions to resolve the unique ID, Vault will update the unique ID. (If it does not have the necessary permissions to resolve the unique ID, then it will fail to update.) If this option is set to false, then you MUST leave out the path component in bound_iam_principal_arn for **roles** only, but not IAM users. That is, if your IAM role ARN is of the form `arn:aws:iam::123456789012:role/some/path/to/MyRoleName`, you **must** specify a bound_iam_principal_arn of `arn:aws:iam::123456789012:role/MyRoleName` for authentication to work.

<ul>
  <li>
    <span class="param">ttl</span>
    <span class="param-flags">optional</span>
    The TTL period of tokens issued using this role, provided as "1h",
    where hour is the largest suffix.
  </li>
</ul>
<ul>
  <li>
    <span class="param">max_ttl</span>
    <span class="param-flags">optional</span>
    The maximum allowed lifetime of tokens issued using this role.
  </li>
</ul>
<ul>
  <li>
    <span class="param">period</span>
    <span class="param-flags">optional</span>
    If set, indicates that the token generated using this role should never
    expire. The token should be renewed within the duration specified by
    this value. At each renewal, the token's TTL will be set to the value
    of this parameter.  The maximum allowed lifetime of tokens issued using
    this role.
  </li>
</ul>
<ul>
  <li>
    <span class="param">policies</span>
    <span class="param-flags">optional</span>
    Policies to be set on tokens issued using this role.
  </li>
</ul>
<ul>
  <li>
    <span class="param">allow_instance_migration</span>
    <span class="param-flags">optional</span>
    If set, allows migration of the underlying instance where the client
    resides. This keys off of pendingTime in the metadata document, so
    essentially, this disables the client nonce check whenever the instance
    is migrated to a new host and pendingTime is newer than the
    previously-remembered time. Use with caution. This only applies to
    authentications via the ec2 auth method.
  </li>
</ul>
<ul>
  <li>
    <span class="param">disallow_reauthentication</span>
    <span class="param-flags">optional</span>
    If set, only allows a single token to be granted per instance ID. In
    order to perform a fresh login, the entry in whitelist for the instance
    ID needs to be cleared using
    'auth/aws/identity-whitelist/<instance_id>' endpoint. Defaults to
    'false'. This only applies to authentications via the ec2 auth method.
  </li>
</ul>

Returns

`204` response code.

GET

Description

Returns the previously registered role configuration.

Method

GET

URL

`/auth/aws/role/`

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "bound_ami_id": "ami-fce36987",
    "role_tag": "",
    "policies": [
      "default",
      "dev",
      "prod"
    ],
    "max_ttl": 1800000,
    "disallow_reauthentication": false,
    "allow_instance_migration": false
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

LIST

Description

Lists all the roles that are registered with the backend.

Method

LIST/GET

URL

`/auth/aws/roles` (LIST) or `/auth/aws/roles?list=true` (GET)

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "keys": [
      "dev-role",
      "prod-role"
    ]
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

DELETE

Description

Deletes the previously registered role.

Method

DELETE

URL

`/auth/aws/role/`

Parameters

None.

Returns

`204` response code.

/auth/aws/role/[role]/tag

POST

Description

Creates a role tag on the role, which help in restricting the capabilities that are set on the role. Role tags are not tied to any specific ec2 instance unless specified explicitly using the `instance_id` parameter. By default, role tags are designed to be used across all instances that satisfies the constraints on the role. Regardless of which instances have role tags on them, capabilities defined in a role tag must be a strict subset of the given role's capabilities. Note that, since adding and removing a tag is often a widely distributed privilege, care needs to be taken to ensure that the instances are attached with correct tags to not let them gain more privileges than what were intended. If a role tag is changed, the capabilities inherited by the instance will be those defined on the new role tag. Since those must be a subset of the role capabilities, the role should never provide more capabilities than any given instance can be allowed to gain in a worst-case scenario.

Method

POST

URL

`/auth/aws/role//tag`

Parameters

• role required Name of the role.

• policies optional Policies to be associated with the tag. If set, must be a subset of the role's policies. If set, but set to an empty value, only the 'default' policy will be given to issued tokens.

• max_ttl optional If set, specifies the maximum allowed token lifetime.

• instance_id optional Instance ID for which this tag is intended for. If set, the created tag can only be used by the instance with the given ID.

• disallow_reauthentication optional If set, only allows a single token to be granted per instance ID. This can be cleared with the auth/aws/identity-whitelist endpoint. Defaults to 'false'.

• allow_instance_migration optional If set, allows migration of the underlying instance where the client resides. This keys off of pendingTime in the metadata document, so essentially, this disables the client nonce check whenever the instance is migrated to a new host and pendingTime is newer than the previously-remembered time. Use with caution. Defaults to 'false'.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "tag_value": "v1:09Vp0qGuyB8=:r=dev-role:p=default,prod:d=false:t=300h0m0s:uPLKCQxqsefRhrp1qmVa1wsQVUXXJG8UZP/pJIdVyOI=",
    "tag_key": "VaultRole"
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

/auth/aws/login

POST

Description

Fetch a token. This endpoint verifies the pkcs7 signature of the instance identity document or the signature of the signed GetCallerIdentity request. With the ec2 auth method, or when inferring an EC2 instance, verifies that the instance is actually in a running state. Cross checks the constraints defined on the role with which the login is being performed. With the ec2 auth method, as an alternative to pkcs7 signature, the identity document along with its RSA digest can be supplied to this endpoint.

Method

POST

URL

`/auth/aws/login`

Parameters

• role optional Name of the role against which the login is being attempted. If `role` is not specified, then the login endpoint looks for a role bearing the name of the AMI ID of the EC2 instance that is trying to login if using the ec2 auth method, or the "friendly name" (i.e., role name or username) of the IAM principal authenticated. If a matching role is not found, login fails.

• identity required Base64 encoded EC2 instance identity document. This needs to be supplied along with the `signature` parameter. If using `curl` for fetching the identity document, consider using the option `-w 0` while piping the output to `base64` binary.

• signature required Base64 encoded SHA256 RSA signature of the instance identity document. This needs to be supplied along with `identity` parameter when using the ec2 auth method.

• pkcs7 required PKCS7 signature of the identity document with all `\n` characters removed. Either this needs to be set *OR* both `identity` and `signature` need to be set when using the ec2 auth method.

• nonce optional The nonce to be used for subsequent login requests. If this parameter is not specified at all and if reauthentication is allowed, then the backend will generate a random nonce, attaches it to the instance's identity-whitelist entry and returns the nonce back as part of auth metadata. This value should be used with further login requests, to establish client authenticity. Clients can choose to set a custom nonce if preferred, in which case, it is recommended that clients provide a strong nonce. If a nonce is provided but with an empty value, it indicates intent to disable reauthentication. Note that, when `disallow_reauthentication` option is enabled on either the role or the role tag, the `nonce` holds no significance. This is ignored unless using the ec2 auth method.

• iam_http_request_method required HTTP method used in the signed request. Currently only POST is supported, but other methods may be supported in the future. This is required when using the iam auth method.

• iam_request_url required Base64-encoded HTTP URL used in the signed request. Most likely just `aHR0cHM6Ly9zdHMuYW1hem9uYXdzLmNvbS8=` (base64-encoding of `https://sts.amazonaws.com/`) as most requests will probably use POST with an empty URI. This is required when using the iam auth method.

• iam_request_body required Base64-encoded body of the signed request. Most likely `QWN0aW9uPUdldENhbGxlcklkZW50aXR5JlZlcnNpb249MjAxMS0wNi0xNQ==` which is the base64 encoding of `Action=GetCallerIdentity&Version=2011-06-15`. This is required when using the iam auth method.

• iam_request_headers required Base64-encoded, JSON-serialized representation of the HTTP request headers. The JSON serialization assumes that each header key maps to an array of string values (though the length of that array will probably only be one). If the `iam_server_id_header_value` is configured in Vault for the aws auth mount, then the headers must include the X-Vault-AWS-IAM-Server-ID header, its value must match the value configured, and the header must be included in the signed headers. This is required when using the iam auth method.

Returns

{
  "auth": {
    "renewable": true,
    "lease_duration": 1800000,
    "metadata": {
      "role_tag_max_ttl": "0",
      "instance_id": "i-de0f1344"
      "ami_id": "ami-fce36983"
      "role": "dev-role",
      "auth_type": "ec2"
    },
    "policies": [
      "default",
      "dev",
    ],
    "accessor": "20b89871-e6f2-1160-fb29-31c2f6d4645e",
    "client_token": "c9368254-3f21-aded-8a6f-7c818e81b17a"
  },
  "warnings": null,
  "data": null,
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

/auth/aws/roletag-blacklist/<role_tag>

POST

Description

Places a valid role tag in a blacklist. This ensures that the role tag cannot be used by any instance to perform a login operation again. Note that if the role tag was previously used to perform a successful login, placing the tag in the blacklist does not invalidate the already issued token.

Method

POST

URL

`/auth/aws/roletag-blacklist/`

Parameters

• role_tag required Role tag to be blacklisted. The tag can be supplied as-is. In order to avoid any encoding problems, it can be base64 encoded.

Returns

`204` response code.

GET

Description

Returns the blacklist entry of a previously blacklisted role tag.

Method

GET

URL

`/auth/aws/broletag-blacklist/`

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "expiration_time": "2016-04-25T10:35:20.127058773-04:00",
    "creation_time": "2016-04-12T22:35:01.178348124-04:00"
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

LIST

Description

Lists all the role tags that are blacklisted.

Method

LIST/GET

URL

`/auth/aws/roletag-blacklist` (LIST) or `/auth/aws/roletag-blacklist?list=true` (GET)

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "keys": [
      "v1:09Vp0qGuyB8=:a=ami-fce3c696:p=default,prod:d=false:t=300h0m0s:uPLKCQxqsefRhrp1qmVa1wsQVUXXJG8UZP/"
    ]
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

DELETE

Description

Deletes a blacklisted role tag.

Method

DELETE

URL

`/auth/aws/roletag-blacklist/`

Parameters

None.

Returns

`204` response code.

/auth/aws/tidy/roletag-blacklist

POST

Description

Cleans up the entries in the blacklist based on expiration time on the entry and `safety_buffer`.

Method

POST

URL

`/auth/aws/tidy/roletag-blacklist`

Parameters

• safety_buffer optional The amount of extra time that must have passed beyond the `roletag` expiration, before it is removed from the backend storage. Defaults to 72h.

Returns

`204` response code.

/auth/aws/identity-whitelist/<instance_id>

GET

Description

Returns an entry in the whitelist. An entry will be created/updated by every successful login.

Method

GET

URL

`/auth/aws/identity-whitelist/`

Parameters

• instance_id required EC2 instance ID. A successful login operation from an EC2 instance gets cached in this whitelist, keyed off of instance ID.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "pending_time": "2016-04-14T01:01:41Z",
    "expiration_time": "2016-05-05 10:09:16.67077232 +0000 UTC",
    "creation_time": "2016-04-14 14:09:16.67077232 +0000 UTC",
    "client_nonce": "5defbf9e-a8f9-3063-bdfc-54b7a42a1f95",
    "role": "dev-role"
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

LIST

Description

Lists all the instance IDs that are in the whitelist of successful logins.

Method

LIST/GET

URL

`/auth/aws/identity-whitelist` (LIST) or `/auth/aws/identity-whitelist?list=true` (GET)

Parameters

None.

Returns

`204` response code.

{
  "auth": null,
  "warnings": null,
  "data": {
    "keys": [
      "i-aab47d37"
    ]
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

DELETE

Description

Deletes a cache of the successful login from an instance.

Method

DELETE

URL

`/auth/aws/identity-whitelist/`

Parameters

None.

Returns

`204` response code.

/auth/aws/tidy/identity-whitelist

POST

Description

Cleans up the entries in the whitelist based on expiration time and `safety_buffer`.

Method

POST

URL

`/auth/aws/tidy/identity-whitelist`

Parameters

• safety_buffer optional The amount of extra time that must have passed beyond the identity expiration, before it is removed from the backend storage. Defaults to 72h.

Returns

`204` response code.