vishalnayak de1a1be564 tidy endpoint fixes

2016-04-26 10:22:29 -04:00

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layout	page_title	sidebar_current	description
docs	Auth Backend: AWS EC2	docs-auth-aws	The AWS EC2 backend allows automated authentication of AWS EC2 instances.

Auth Backend: AWS EC2

The AWS EC2 auth backend provides a secure introduction mechanism for AWS EC2 instances, allowing automated retrieval of a Vault token. Unlike most Vault authentication backends, this backend does not require first deploying or provisioning security-sensitive credentials (tokens, username/password, client certificates, etc). Instead, it treats AWS as a Trusted Third Party and uses the cryptographically signed dynamic metadata information that uniquely represents each EC2 instance.

Authentication Workflow

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. Importantly, AWS also provides a copy of this metadata in PKCS#7 format signed with its public key, and publishes the public keys used (which are grouped by region). (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.

Authorization Workflow

The basic mechanism of operation is per-AMI. AMI IDs are registered in the backend and associated with various optional restrictions, such as the set of allowed policies and max TTLs on the generated tokens.

In many cases, an organization will use a "seed AMI" that is specialized after bootup by configuration management or similar processes. For this reason, an AMI entry in the backend can also be associated with a "role tag". 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 image, but cannot be used to grant additional privileges.

The role tags can be generated at will by an operator with appropriate API access. They are HMAC-signed by a 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.

Client Nonce

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 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. However, this has consequences for token rotation, as it means that once a token has expired, subsequent authentication attempts would fail.

The backend addresses this problem by sharing the responsibility with clients. In the default method of operation, the client supplies a unique nonce during the first authentication attempt, storing this nonce in the client's memory for future use. This nonce is stored in the whitelist, tied to the instance ID. Subsequent authentication attempts by the client require the nonce to match; 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.)

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

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 with the given AMI. 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 AMI and are used to further restrict the set of the AMI's privileges for that particular instance.

A role_tag can be created using auth/aws/image/<ami_id>/roletag endpoint and is immutable. The information present in the tag is SHA256 hashed and HMAC protected. The 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 the role_tag option is set on an AMI, failure to provide any role tag at all results in a login failure. If the role tag has no policy component, the client will inherit the allowed policies set on the AMI. If the role tag has a 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

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/whitelist/identity/<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-AMI. 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.

Disabling Reauthentication

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).

The disallow_reauthentication option is set per-AMI, 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 AMI, a value of true in the role tag takes effect; however, if the option is set to true on the AMI, a value set in the role tag has no effect.

Blacklisting Role Tags

Role tags are tied to a specific AMI, but the backend has no control over which instances using that AMI should have any particular role tag; that is purely up to the operator. Although role tags are only restrictive, 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/blacklist/roletag/<role_tag>. Note that this will not invalidate the tokens that were already issued; this only blocks any further login requests.

Expiration Times and Tidying of `blacklist` and `whitelist` Entries

The entries in both identity whitelist and role tag blacklist are not deleted automatically, as the amount of time they are required to be valid are likely to vary with organizational policy. The entries in both of these lists contain an expiration time which is dynamically determined by three factors: max_ttl set on the AMI, 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/identities and aws/auth/tidy/roletags 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.

Additionally, the backend performs has a periodic function that does the tidying of both blacklist role tags and whitelist identities. This periodic tidying is activated by default and will have a safety buffer of 72 hours. This can be configured via config/tidy/roletags and config/tidy/identities endpoints.

Varying Public Certificates

The AWS public certificate which contains the public key used to verify the PKCS#7 signature varies for groups of regions. The default public certificate provided with the backend is applicable many regions. Users of instances whose signatures cannott be verified by the default public certificate, 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.

Authentication

Via the CLI

Enable AWS EC2 authentication in Vault.

$ vault auth-enable aws

Configure the credentials required to make AWS API calls

Note: the client uses the official AWS SDK and will use environment variable or IAM role-provided credentials if available. In addition, the AWS_REGION environment variable will be honored if available.

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

Configure the policies on the AMI.

$ vault write auth/aws/image/ami-fce3c696 policies=prod,dev max_ttl=500h

$ vault write auth/aws/login pkcs7=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 nonce=vault-client-nonce

Via the API

Enable AWS EC2 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 AMI.

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

curl -X POST "http://127.0.0.1:8200/v1/auth/aws/login" -d '{"pkcs7":"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","nonce":"vault-client-nonce"}'

The response will be in JSON. For example:

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

API

/auth/aws/config/client

POST

Description

Configures the credentials required to perform API calls to AWS. 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 DescribeInstanceStatus API. Also, if the login is performed using the role tag, then these credentials will also be used to fetch the tags that are set on the EC2 instance via DescribeTags API. If the 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 required AWS Access key with permissions to query EC2 instance metadata.

secret_key required AWS Secret key with permissions to query EC2 instance metadata.

Returns

`204` response code.

GET

Description

Method

GET

URL

`/auth/aws/config/client`

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "secret_key": "vCtSM8ZUEQ3mOFVlYPBQkf2sO6F/W7a5TVzrl3Oj",
    "access_key": "VKIAJBRHKH6EVTTNXDHA"
  },
  "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 that is used to verify the PKCS#7 signature of the EC2 instance metadata.

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.

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

GET

URL

`/auth/aws/config/certificates?list=true`

Parameters

None.

Returns

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

/auth/aws/config/tidy/identities

POST

Description

Configures the periodic tidying operation of the whitelisted identity entries.

Method

POST

URL

`/auth/aws/config/tidy/identities`

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 'whitelist/identity/' entries and 'whitelist/identity/' entries.

Returns

`204` response code.

GET

Description

Returns the previously configured periodic whitelist tidying settings.

Method

GET

URL

`/auth/aws/config/tidy/identities`

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/identities`
Parameters: None.
Returns: `204` response code.

/auth/aws/config/tidy/roletags

POST

Description

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

Method

POST

URL

`/auth/aws/config/tidy/roletags`

Parameters

<ul>
  <li>
    <span class="param">safety_buffer</span>
    <span class="param-flags">optional</span>
    The amount of extra time that must have passed beyond the `roletag` expiration, before it is removed from the backend storage. Defaults to 72h.
  </li>
</ul>
<ul>
  <li>
    <span class="param">disable_periodic_tidy</span>
    <span class="param-flags">optional</span>
    If set to 'true', disables the periodic tidying of the 'blacklist/roletag/<role_tag>' entries and 'whitelist/identity/<instance_id>' entries.
  </li>
</ul>

Returns

`204` response code.

GET

Description

Returns the previously configured periodic blacklist tidying settings.

Method

GET

URL

`/auth/aws/config/tidy/roletags`

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/roletags`
Parameters: None.
Returns: `204` response code.

/auth/aws/image/<ami_id>

POST

Description

Registers an AMI ID in the backend. Only those instances which are using the AMIs registered using this endpoint, will be able to perform login operation. If each EC2 instance is using unique AMI ID, then all those AMI IDs should be registered beforehand. In case the same AMI is shared among many EC2 instances, then that AMI should be registered using this endpoint with the option `role_tag` (refer API section), then a `roletag` should be created using `auth/aws/image//roletag` endpoint, and this tag should be attached to the EC2 instance before the login operation is performed.

Method

POST

URL

`/auth/aws/image/`

Parameters

ami_id required AMI ID to be mapped.

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.

role_tag optional If set, enables the `roletag` login for this AMI, meaning that this AMI is shared among many EC2 instances. The value set for this field should be the `key` of the tag on the EC2 instance and the `tag_value` returned from `auth/aws/image//roletag` should be the `value` of the tag on the instance. Defaults to empty string, meaning that this AMI is not shared among instances.

max_ttl optional The maximum allowed lease duration.

policies optional Policies to be associated with the AMI.

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.

disallow_reauthentication optional 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/whitelist/identity/' endpoint. Defaults to 'false'.

Returns

`204` response code.

GET

Description

Returns the previously registered AMI ID configuration.

Method

GET

URL

`/auth/aws/image/`

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "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 AMI IDs that are registered with the backend.

Method

GET

URL

`/auth/aws/images?list=true`

Parameters

None.

Returns

{
  "auth": null,
  "warnings": null,
  "data": {
    "keys": [
      "ami-fce3c696",
      "ami-hei3d687"
    ]
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

DELETE

Description: Deletes the previously registered AMI ID.
Method: DELETE
URL: `/auth/aws/image/`
Parameters: None.
Returns: `204` response code.

/auth/aws/image/<ami_id>/roletag

POST

Description

Creates a `roletag` for the AMI_ID. Role tags provide an effective way to restrict the options that are set on the AMI ID. This is of use when AMI is shared by multiple instances and there is need to customize the options for specific instances.

Method

POST

URL

`/auth/aws/image//roletag`

Parameters

ami_id required AMI ID to create a tag for.

policies optional Policies to be associated with the tag.

max_ttl optional The maximum allowed lease duration.

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

Returns

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

POST

Description

Login and fetch a token. If the instance metadata signature is valid along with a few other conditions, a token will be issued.

Method

POST

URL

`/auth/aws/login`

Parameters

pkcs7 required PKCS7 signature of the identity document.

nonce required/optional, depends The `nonce` created by a client of this backend. When `disallow_reauthentication` option is enabled on either the AMI or the role tag, then `nonce` parameter is optional. It is a required parameter otherwise.

Returns

{
  "auth": {
    "renewable": true,
    "lease_duration": 1800000,
    "metadata": {
      "role_tag_max_ttl": "0",
      "instance_id": "i-de0f1344"
    },
    "policies": [
      "default",
      "dev",
      "prod"
    ],
    "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/blacklist/roletag/<role_tag>

POST

Description

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

Method

POST

URL

`/auth/aws/blacklist/roletag/`

Parameters

role_tag required Role tag that needs be blacklisted. The tag can be supplied as-is, or can be base64 encoded.

Returns

`204` response code.

GET

Description

Returns the blacklist entry of a previously blacklisted `roletag`.

Method

GET

URL

`/auth/aws/blacklist/roletag/`

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 `roletags` that are blacklisted.

Method

GET

URL

`/auth/aws/blacklist/roletag?list=true`

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 `roletag`.
Method: DELETE
URL: `/auth/aws/blacklist/roletag/`
Parameters: None.
Returns: `204` response code.

/auth/aws/tidy/roletags

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/roletags`

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/whitelist/identity/<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/whitelist/identity/`

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": "vault-client-nonce",
    "ami_id": "ami-fce3c696"
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}

LIST

Description

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

Method

GET

URL

`/auth/aws/whitelist/identity?list=true`

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/whitelist/identity/`
Parameters: None.
Returns: `204` response code.

/auth/aws/tidy/identities

POST

Description

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

Method

POST

URL

`/auth/aws/tidy/identities`

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.

38 KiB Raw Blame History

Auth Backend: AWS EC2

Authentication Workflow

Authorization Workflow

Client Nonce

Advanced Options and Caveats

Dynamic Management of Policies Via Role Tags

Handling Lost Client Nonces

Disabling Reauthentication

Blacklisting Role Tags

Expiration Times and Tidying of blacklist and whitelist Entries

Varying Public Certificates

Authentication

Via the CLI

Enable AWS EC2 authentication in Vault.

Configure the credentials required to make AWS API calls

Configure the policies on the AMI.

Perform the login operation

Via the API

Enable AWS EC2 authentication in Vault.

Configure the credentials required to make AWS API calls.

Configure the policies on the AMI.

Perform the login operation

API

/auth/aws/config/client

POST

GET

DELETE

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

POST

GET

LIST

/auth/aws/config/tidy/identities

POST

GET

DELETE

/auth/aws/config/tidy/roletags

POST

GET

DELETE

/auth/aws/image/<ami_id>

POST

GET

LIST

DELETE

/auth/aws/image/<ami_id>/roletag

POST

/auth/aws/login

POST

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

POST

GET

LIST

DELETE

/auth/aws/tidy/roletags

POST

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

GET

LIST

DELETE

/auth/aws/tidy/identities

POST

38 KiB

Raw Blame History

Expiration Times and Tidying of `blacklist` and `whitelist` Entries