Yoko Hyakuna ac4bd212fc WIP - new guides

2018-01-17 17:39:21 -08:00

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layout	page_title	sidebar_current	description
guides	Tokens and Leases - Guides	guides-lease	Tokens are the core method for authentication within Vault. For every authentication token and dynamic secret, Vault creates a lease containing information such as a duration, renewability, and more. Understanding the lifecycle of lease means understanding the lifecycle of tokens on some sense.

Tokens and Leases

Almost everything in Vault has an associated lease, and when the lease is expired, the secret is revoked. Tokens are not an exception. Every non-root token has a time-to-live (TTL) associated with it. When a token expires and it's not renewed, the token automatically gets revoked.

Lease Hierarchy

When a new token or secret is created, it is a child of the creator. If the parent is revoked or expires, so do all its children regardless of their own leases. A child may be a token, secret, or authentication created by a parent. A parent is almost always a token.

Suppose a hierarchy exists with respective TTL as follow:

b519c6aa... (3h)
    6a2cf3e7... (4h)
    1d3fd4b2... (1h)
        794b6f2f... (2h)

In this scenario, the lease ID of 1d3fd4b2.. will expire in an hour. If a token or secret with a lease is not renewed before the lease expires, it will be revoked by the Vault server. When it's revoked, it takes its child (794b6f2f...) although the child has one more hour before it expires. Then, two hours later, b519c6aa... will be revoked and takes its child (6a2cf3e7...) with it.

Reference Material

The Validation section of the Secret as a Service guide demonstrated lease renewal and revocation
Tokens documentation
Token Auth Backend HTTP API
Lease, Renew, and Revoke

Estimated Time to Complete

10 minutes

Challenge

Consider the following scenarios:

Currently, there is no break glass procedure available
Credentials for externals systems (e.g. AWS, MySQL) are shared
Need a temporal access to database in a specific scenario

Solution

Vault has built-in support for secret revocation. Vault can revoke not only single secret, but also a tree of secrets. For example, Vault can revoke all secrets read by a specific user or all secrets of a specific type. Revocation assists in key rolling as well as locking down systems in the case of an intrusion. This also allows for organizations to plan and train for various "break glass" procedures.

Prerequisites

To perform the tasks described in this guide, you need to have a Vault environment. Refer to the Getting Started guide to install Vault.

Make sure that your Vault server has been initialized and unsealed.

Steps

Tokens are the core methods for authentication within Vault. Tokens can be used directly or dynamically generated by the auth backends. Regardless, the clients need valid tokens to interact with Vault.

This guide demonstrates the lifecycle of tokens.

Read token backend configuration
Create short-live tokens
Create tokens with use limit
Periodic tokens
Orphan tokens
Revoke tokens

Step 1: Read token backend configuration

When you create leases with no specific TTL values, the default value applies to the lease.

vault auth -methods

Path       Type      Accessor                Default TTL  Max TTL  Replication Behavior  Description
approle/   approle   auth_approle_53f0fb08   system       system   replicated
github/    github    auth_github_b770f4c8    system       system   replicated
token/     token     auth_token_2ad69043     system       system   replicated            token based credentials
userpass/  userpass  auth_userpass_d326d2f9  system       system   replicated

The system max TTL is 32 days, but you can override it to be longer or shorter in Vault's configuration file.

Another option is to tune the mount configuration to override the system defaults by calling the /sys/mounts/<PATH>/tune endpoint (e.g. /sys/mounts/database/tune). For the auth backend system configuration, call /sys/auth/<METHOD>/tune endpoint. See the Reference Content for more detail.

CLI command

Read the default TTL settings for token auth backend:

vault read sys/auth/token/tune

Key              	Value
---              	-----
default_lease_ttl	2764800
force_no_cache   	false
max_lease_ttl    	2764800

API call using cURL

Before begin, create the following environment variables for your convenience:

VAULT_ADDR is set to your Vault server address
VAULT_TOKEN is set to your Vault token

Example:

$ export VAULT_ADDR=http://127.0.0.1:8201

$ export VAULT_TOKEN=0c4d13ba-9f5b-475e-faf2-8f39b28263a5

Read the default TTL settings for token auth backend:

$ curl -X GET -H "X-Vault-Token: $VAULT_TOKEN" $VAULT_ADDR/v1/sys/auth/token/tune | jq
{
  "default_lease_ttl": 2764800,
  "max_lease_ttl": 2764800,
  "force_no_cache": false,
  "request_id": "630fd49d-f704-540f-0641-41516087654f",
  "lease_id": "",
  "renewable": false,
  "lease_duration": 0,
  "data": {
    "default_lease_ttl": 2764800,
    "force_no_cache": false,
    "max_lease_ttl": 2764800
  },
  "wrap_info": null,
  "warnings": null,
  "auth": null
}

-> NOTE: The returned TTL value is in seconds (2764800 seconds = 32 days).

Step 2: Create short-live tokens

Create a new token with TTL of 30 seconds.

CLI command

$ vault token-create -ttl=30s
Key            	Value
---            	-----
token          	7544266f-3ec9-81a6-d504-e258b89de862
token_accessor 	59aae2f1-2e97-6ebb-f925-8a97cf5a9942
token_duration 	30s
token_renewable	true
token_policies 	[root]

$ VAULT_TOKEN=3b2b1285-844b-4b40-6afa-623f39c1b738 vault token-lookup
Key             	Value
---             	-----
accessor        	2b2b5b83-7f22-fecd-03f0-4e25bf64da11
creation_time   	1515702047
creation_ttl    	30
display_name    	token
expire_time     	2018-01-11T20:21:17.900969673Z
explicit_max_ttl	0
id              	3b2b1285-844b-4b40-6afa-623f39c1b738
issue_time      	2018-01-11T20:20:47.90096937Z
meta            	<nil>
num_uses        	0
orphan          	false
path            	auth/token/create
policies        	[root]
renewable       	true
ttl             	8

NOTE: The vault token-lookup command returns the token's properties. In this example, it shows that this token has 8 more seconds before it expires.

When you execute a vault command using the new token immediately following its creation, it should work. Wait for 30 seconds and try again. It returns Code: 403. Errors: which indicates a forbidden API call due to expired token usage.

You can renew the token's TTL as long as the token has not expired, yet.

vault token-renew <TOKEN>

If you want to renew and extend the token's TTL, pass the desired extension:

vault token-renew <TOKEN> <EXTENSION>

The extension value can be an integer number of seconds (e.g. 3600) or a string duration (e.g. "1h").

API call using cURL

curl -X POST -H "X-Vault-Token: $VAULT_TOKEN" -d '{"ttl": "30s"}' \
   $VAULT_ADDR/v1/auth/token/create | jq

{
  ...
 "auth": {
   "client_token": "f7d88963-1aba-64d7-11a0-9282ae7681d0",
   "accessor": "c0a40d94-b814-e46f-7e56-ee18fccdf1b6",
   "policies": [
     "root"
   ],
   "metadata": null,
   "lease_duration": 30,
   "renewable": true
 }
}

Verification

curl -X GET -H "X-Vault-Token: f7d88963-1aba-64d7-11a0-9282ae7681d0" \
   $VAULT_ADDR/v1/auth/token/lookup-self | jq

{
  ...
 "data": {
   "accessor": "a54fea3f-6c09-d288-ede5-53288569f988",
   "creation_time": 1515702669,
   "creation_ttl": 30,
    ...
   "renewable": true,
   "ttl": 14
 },
 ...
}

When you invoke the API using the new token immediately following its creation, it should work. Wait for 30 seconds and try again. It returns Code: 403. Errors: which indicates a forbidden API call due to expired token usage.

Renew the token:

$ curl -X POST -H "X-Vault-Token: $VAULT_TOKEN" $VAULT_ADDR/v1/auth/token/renew/<TOKEN> | jq

$ curl -X POST -H "X-Vault-Token: $VAULT_TOKEN" -d '{"increment": "3600"}' \
    $VAULT_ADDR/v1/auth/token/renew/<TOKEN> | jq

-> NOTE: Tokens can be renewed as long as its life hasn't reached its max TTL. For example, if the token's TTL is 1 hour and max TTL is 24 hours, you can renew the token up to 24 hours from its creation time. Once 24 hours past from the token's creation time, it gets revoked by Vault. For a long running processes, this may introduce complexity. In such case, use periodic tokens.

Step 3: Create tokens with use limit

In addition to TTL and max TTL, tokens may be limited to a number of uses. Use limit tokens expire at the end of their last use regardless of their remaining TTLs. On the same note, use limit tokens expire at the end of their TTLs regardless of their remaining uses.

To create tokens with use limit, simply set the number of use when you create them.

CLI command

Create a token with -use-limit property argument.

Example:

vault token-create -policy=default -use-limit=2

Key            	Value
---            	-----
token          	bd39178e-176e-cc91-3930-94f7b0194de5
token_accessor 	a230f5ab-b59f-db0b-855d-36ea4319b58e
token_duration 	768h0m0s
token_renewable	true
token_policies 	[default]

This creates a token with default policy with use limit of 2.

Verification

$ VAULT_TOKEN=bd39178e-176e-cc91-3930-94f7b0194de5 vault token-lookup

Key             	Value
---             	-----
accessor        	a230f5ab-b59f-db0b-855d-36ea4319b58e
creation_time   	1515710251
creation_ttl    	2764800
display_name    	token
expire_time     	2018-02-12T22:37:31.715486503Z
explicit_max_ttl	0
id              	bd39178e-176e-cc91-3930-94f7b0194de5
issue_time      	2018-01-11T22:37:31.715486221Z
meta            	<nil>
num_uses        	1
orphan          	false
path            	auth/token/create
policies        	[default]
renewable       	true
ttl             	2764769


$ VAULT_TOKEN=bd39178e-176e-cc91-3930-94f7b0194de5 vault write cubbyhole/token \
    value=bd39178e-176e-cc91-3930-94f7b0194de5

Success! Data written to: cubbyhole/token


$ VAULT_TOKEN=bd39178e-176e-cc91-3930-94f7b0194de5 vault read cubbyhole/token
Error reading cubbyhole/token: Error making API request.

URL: GET http://127.0.0.1:8200/v1/cubbyhole/token
Code: 403. Errors:

* permission denied

First command read the token properties, and then wrote a value to cubbyhole secret backend. This exhausted the use limit of 2 for this token. Therefore, the attempt to read the secret from cubbyhole failed.

API call using cURL

Set the num_uses property in the request payload.

curl -X POST -H "X-Vault-Token: $VAULT_TOKEN" -d '{ "policies": ["default"], "num_uses":2 }' \
  $VAULT_ADDR/v1/auth/token/create | jq

{
  "request_id": "0e98ff80-2825-7f50-6522-b6f95d596ef4",
  "lease_id": "",
  "renewable": false,
  "lease_duration": 0,
  "data": null,
  "wrap_info": null,
  "warnings": null,
  "auth": {
    "client_token": "d9c2f2e5-6b8a-4021-476c-ebd3f166d668",
    "accessor": "4dd5ef0d-8515-c3ae-ea49-016c3e9eb968",
    "policies": [
      "default"
    ],
    "metadata": null,
    "lease_duration": 2764800,
    "renewable": true
  }
}

This creates a token with default policy with use limit of 2.

Verification

$ curl -X GET -H "X-Vault-Token: d9c2f2e5-6b8a-4021-476c-ebd3f166d668" \
    $VAULT_ADDR/v1/auth/token/lookup-self | jq
{
  "request_id": "77be1321-c0ca-e099-6f92-4ad87133b044",
  "lease_id": "",
  "renewable": false,
  "lease_duration": 0,
  "data": {
    "accessor": "4dd5ef0d-8515-c3ae-ea49-016c3e9eb968",
    "creation_time": 1515711922,
    "creation_ttl": 2764800,
    "display_name": "token",
    "expire_time": "2018-02-12T23:05:22.746137253Z",
    "explicit_max_ttl": 0,
    "id": "d9c2f2e5-6b8a-4021-476c-ebd3f166d668",
    "issue_time": "2018-01-11T23:05:22.746136892Z",
    "meta": null,
    "num_uses": 1,
    ...
}

$ curl -X POST -H "X-Vault-Token: d9c2f2e5-6b8a-4021-476c-ebd3f166d668" \
    -d '{ "value": "d9c2f2e5-6b8a-4021-476c-ebd3f166d668" }' $VAULT_ADDR/v1/cubbyhole/token


$ curl -X GET -H "X-Vault-Token: d9c2f2e5-6b8a-4021-476c-ebd3f166d668" $VAULT_ADDR/v1/cubbyhole/token | jq

{
  "errors": [
    "permission denied"
  ]
}

Step 4: Periodic tokens

Root or sudo users have the ability to generate periodic tokens. Periodic tokens have a TTL, but no max TTL; therefore, it may live for an infinite duration of time so long as they are renewed within their TTL. This is useful for long-running services that cannot handle regenerating a token.

CLI command

First, create a token role with a specific period. When you set period, tokens created for this role will have no max TTL. Instead, the period becomes the token renewal period. This value can be an integer value in seconds (e.g. 2764800) or a string duration (e.g. 72h).

vault write auth/token/roles/<ROLE_NAME> allowed_policies="<POLICY_NAMES>" period=<RENEWAL_PERIOD>

Example:

vault write auth/token/roles/zabbix allowed_policies="zabbix-pol, default" period="24h"

Now, generate a token:

vault token-create -role=zabbix

Key            	Value
---            	-----
token          	de91ebba-20ad-18ba-fa43-08e1932de301
token_accessor 	1f8abad0-c1db-9399-15ee-dd4b6230386c
token_duration 	24h0m0s
token_renewable	true
token_policies 	[default zabbix-pol]

API call using cURL

First, create a token role by setting period. When you set period, tokens created for this role will have no max TTL. Instead, the period becomes the token renewal period. This value can be an integer value in seconds (e.g. 2764800) or a string duration (e.g. 72h).

Example:

$ curl -X POST -H "X-Vault-Token: $VAULT_TOKEN" -d @token-role.json \
    $VAULT_ADDR/v1/auth/token/roles/zabbix

$ cat token-role.json

{
	"allowed_policies": [
		"default",
		"zabbix-pol"
	],
	"period": "24h"
}

This creates a token role named zabbix with default and zabbix-pol policies attached. Also, its renewal period is set to 24 hours.

Now, generate a token:

curl -X POST -H "X-Vault-Token: $VAULT_TOKEN" $VAULT_ADDR/v1/auth/token/create/zabbix | jq

{
  ...
  "auth": {
    "client_token": "a59c0d41-8df7-ba8e-477e-9bfb394f28a0",
    "accessor": "c2023006-ce8d-532b-136f-330223ccf464",
    "policies": [
      "default",
      "zabbix-pol"
    ],
    "metadata": null,
    "lease_duration": 86400,
    "renewable": true,
    "entity_id": ""
  }

-> Generated tokens are renewable indefinitely for as long as it gets renewed before its lease duration expires. The token renew command was covered in Step 2.

Periodic Tokens with AppRole

It probably makes better sense to create AppRole periodic tokens since we are talking about long-running apps need to be able to renew its token indefinitely. To create AppRole periodic tokens, create your AppRole role with period specified.

Example:

vault write auth/approle/role/jenkins policies="dev-pol,devops-pol" period="72h"

$ curl -X POST -H "X-Vault-Token:$VAULT_TOKEN" -d @payload.json \
    $VAULT_ADDR/v1/auth/approle/role/jenkins

$ cat payload.json
{
  "allowed_policies": [
		"dev-pol",
		"devops-pol"
	],
  "period": "72h"  
}

For more details about AppRole, refer to Authentication - AppRole guide.

Step 5: Orphan tokens

Root or sudo users have the ability to generate orphan tokens. Orphan tokens are not children of their parent; therefore, it does not expire when their parent does.

NOTE: Orphan tokens still expire when their own max TTL is reached.

CLI command

vault token-create -orphan

API call using cURL

$ curl -X POST -H "X-Vault-Token:$VAULT_TOKEN" -d '{ "no_parent": true }' \
    $VAULT_ADDR/v1/auth/token/create-orphan | jq

Step 6: Revoke tokens

Revoking a token and all its children.

CLI command

To revoke a specific token:

vault token-revoke <TOKEN>

To revoke all tokens under a specific path:

vault token-revoke -prefix <PATH>

Example:

# Revoke a specific token
$ vault token-revoke eeaf890e-4b0f-a687-4190-c75b1d6d70bc

# Revoke all secrets for database auth backend
$ vault token-revoke -prefix database/creds

# Revoke all tokens
$ vault token-revoke -prefix auth/token/create

API call using cURL

To revoke a specific token, call /auth/token/revoke endpoint. If you want to revoke tokens/secrets under a specific path, call /sys/leases/revoke-prefix/<PATH>.

Example:


# Revoke a specific token
$ curl -X POST -H "X-Vault-Token:$VAULT_TOKEN" -d '{ "token": "eeaf890e-4b0f-a687-4190-c75b1d6d70bc" }' \
    $VAULT_ADDR/v1/auth/token/revoke

# Revoke all secrets for database auth backend
$ curl -X POST -H "X-Vault-Token:$VAULT_TOKEN" $VAULT_ADDR/v1/sys/leases/revoke-prefix/database/creds

# Revoke all tokens
$ curl -X POST -H "X-Vault-Token:$VAULT_TOKEN" $VAULT_ADDR/v1/sys/leases/revoke-prefix/auth/token/create

Advanced Features

It is important to understand the lease configuration to avoid having your secret leases expiring earlier than you expected.

1. Determine the TTLs specific to the mount

$ vault mounts

Path        Type       Accessor            Plugin  Default TTL  Max TTL  Force No Cache  Replication Behavior  Seal Wrap  Description
cubbyhole/  cubbyhole  cubbyhole_36021b8e  n/a     n/a          n/a      false           local                 false      per-token private secret storage
database/   database   database_e21b9b4f   n/a     system       system   false           replicated            false
identity/   identity   identity_035fe03b   n/a     n/a          n/a      false           replicated            false      identity store
pki/        pki        pki_9ae09eb3        n/a     system       system   false           replicated            false
secret/     kv         kv_2e59ba96         n/a     system       system   false           replicated            false      key/value secret storage
ssh/        ssh        ssh_ea06b9bb        n/a     system       system   false           replicated            false
sys/        system     system_f5b5ecac     n/a     n/a          n/a      false           replicated            false      system endpoints used for control, policy and debugging
transit/    transit    transit_07fc2df9    n/a     system       system   false           replicated            false

2. Tune the system TTLs

Override the global defaults by specifying default_lease_ttl and max_lease_ttl to meet your requirements.

Example:

$ vault write sys/mounts/database/tune default_lease_ttl="8640"

$ curl -X POST -H "X-Vault-Token:$VAULT_TOKEN" -d `{ "max_lease_ttl": 129600}`\
    $VAULT_ADDR/v1/sys/mounts/database/tune

3. Check the role specific TTLs

Depending on the backend, there may be more specific TTLs configured (e.g. roles, groups, users) as you have done so in Step 4.

$ vault read auth/token/roles/zabbix

Key                	Value
---                	-----
allowed_policies   	[default zabbix-pol]
disallowed_policies	[]
explicit_max_ttl   	0
name               	zabbix
orphan             	false
path_suffix
period             	86400
renewable          	true

20 KiB Raw Blame History

Tokens and Leases

Lease Hierarchy

Reference Material

Estimated Time to Complete

Challenge

Solution

Prerequisites

Steps

Step 1: Read token backend configuration

CLI command

API call using cURL

Step 2: Create short-live tokens

CLI command

API call using cURL

Verification

Renew the token:

Step 3: Create tokens with use limit

CLI command

Verification

API call using cURL

Verification

Step 4: Periodic tokens

CLI command

API call using cURL

Periodic Tokens with AppRole

Step 5: Orphan tokens

CLI command

API call using cURL

Step 6: Revoke tokens

CLI command

API call using cURL

Advanced Features

1. Determine the TTLs specific to the mount

2. Tune the system TTLs

3. Check the role specific TTLs

Next steps

20 KiB

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