---
layout: api
page_title: Kerberos - Auth Methods - HTTP API
description: This is the API documentation for the Vault Kerberos auth method plugin.
---

# Kerberos auth method (API)

@include 'x509-sha1-deprecation.mdx'

This is the API documentation for the Vault Kerberos auth method plugin. To
learn more about the usage and operation, see the
[Vault Kerberos auth method](/vault/docs/auth/kerberos).

This documentation assumes the Kerberos auth method is mounted at the
`auth/kerberos` path in Vault. Since it is possible to enable auth methods at
any location, please update your API calls accordingly.

The Kerberos auth method validates both Kerberos and LDAP authorization,
so both configurations are required.

## Configure Vault Kerberos

This endpoint configures the keytab and service account to be used by Vault
for verifying inbound SPNEGO tokens.

| Method | Path                    |
| :----- | :---------------------- |
| `POST` | `/auth/kerberos/config` |

- `keytab` `(string: <required>)` – A base 64 representation of the contents
  of the Kerberos keytab that will be used for verifying inbound SPNEGO tokens.
  It should contain an entry matching the service account given. This can be
  created through the following command: `$ base64 vault.keytab > vault.keytab.base64`.
- `service_account` `(string: <required>)` – The service account associated
  with both the keytab entry and an LDAP service account created for Vault. Ex.:
  `"vault_svc"`.
- `remove_instance_name` - Removes any instance names from a Kerberos service
  principal name when parsing the keytab file. For example when this is set to true,
  if a keytab has the service principal name `foo/localhost@example.com`, Vault
  will strip the service principal name to just be `foo@example.com`. 
- `add_group_aliases` - When set to true, Vault will add any LDAP groups found for 
  the user as group aliases.

### Sample request

```shell-session
$ curl \
    --header "X-Vault-Token: ..." \
    --request POST \
    --data @payload.json \
    http://127.0.0.1:8200/v1/auth/kerberos/config
```

### Sample payload

```json
{
  "add_group_aliases": false,
  "keytab": "BQIAAAA6AAEACk1BVFJJWC5MQU4ACXZhdWx0X3N2YwAAAAFdzZSjAgAXABDwhEyRR9nRqkpP8KTn2A83AAAAAg==",
  "remove_instance_name": false,
  "service_account": "vault_svc"
}
```

## Read Vault Kerberos

This endpoint retrieves the service account for the Kerberos auth method.
The keytab is not returned because it is sensitive information.

| Method | Path                    |
| :----- | :---------------------- |
| `GET`  | `/auth/kerberos/config` |

### Sample request

```shell-session
$ curl \
    --header "X-Vault-Token: ..." \
    http://127.0.0.1:8200/v1/auth/kerberos/config
```

### Sample response

```json
{
  "auth": null,
  "warnings": null,
  "wrap_info": null,
  "data": {
    "add_group_aliases": false,
    "remove_instance_name": false,
    "service_account": "vault_svc"
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}
```

## Configure Kerberos LDAP

This endpoint configures LDAP in the Kerberos auth method.

| Method | Path                         |
| :----- | :--------------------------- |
| `POST` | `/auth/kerberos/config/ldap` |

### Parameters

- `url` `(string: <required>)` – The LDAP server to connect to. Examples:
  `ldap://ldap.myorg.com`, `ldaps://ldap.myorg.com:636`. Multiple URLs can be
  specified with commas, e.g. `ldap://ldap.myorg.com,ldap://ldap2.myorg.com`;
  these will be tried in-order.
- `case_sensitive_names` `(bool: false)` – If set, user and group names
  assigned to policies within the backend will be case sensitive. Otherwise,
  names will be normalized to lower case. Case will still be preserved when
  sending the username to the LDAP server at login time; this is only for
  matching local user/group definitions.
- `starttls` `(bool: false)` – If true, issues a `StartTLS` command after
  establishing an unencrypted connection.
- `tls_min_version` `(string: tls12)` – Minimum TLS version to use. Accepted
  values are `tls10`, `tls11`, `tls12` or `tls13`.
- `tls_max_version` `(string: tls12)` – Maximum TLS version to use. Accepted
  values are `tls10`, `tls11`, `tls12` or `tls13`.
- `insecure_tls` `(bool: false)` – If true, skips LDAP server SSL certificate
  verification - insecure, use with caution!
- `certificate` `(string: "")` – CA certificate to use when verifying LDAP server
  certificate, must be x509 PEM encoded.
- `binddn` `(string: "")` – Distinguished name of object to bind when performing
  user search. Example: `cn=vault,ou=Users,dc=example,dc=com`
- `bindpass` `(string: "")` – Password to use along with `binddn` when performing
  user search.
- `userdn` `(string: "")` – Base DN under which to perform user search. Example:
  `ou=Users,dc=example,dc=com`
- `userattr` `(string: "")` – Attribute on user attribute object matching the
  username passed when authenticating. Examples: `sAMAccountName`, `cn`, `uid`
- `discoverdn` `(bool: false)` – Use anonymous bind to discover the bind DN of a
  user.
- `deny_null_bind` `(bool: true)` – This option prevents users from bypassing
  authentication when providing an empty password.
- `upndomain` `(string: "")` – The _userPrincipalDomain_ used to construct the UPN
  string for the authenticating user. The constructed UPN will appear as
  `[username]@UPNDomain`. Example: `example.com`, which will cause vault to bind
  as `username@example.com`.
- `groupfilter` `(string: "")` – Go template used when constructing the group
  membership query. The template can access the following context variables:
  \[`UserDN`, `Username`\]. The default is
  `(|(memberUid={{.Username}})(member={{.UserDN}})(uniqueMember={{.UserDN}}))`,
  which is compatible with several common directory schemas. To support
  nested group resolution for Active Directory, instead use the following
  query: `(&(objectClass=group)(member:1.2.840.113556.1.4.1941:={{.UserDN}}))`.
- `groupdn` `(string: "")` – LDAP search base to use for group membership
  search. This can be the root containing either groups or users. Example:
  `ou=Groups,dc=example,dc=com`
- `groupattr` `(string: "")` – LDAP attribute to follow on objects returned by
  `groupfilter` in order to enumerate user group membership. Examples: for
  groupfilter queries returning _group_ objects, use: `cn`. For queries
  returning _user_ objects, use: `memberOf`. The default is `cn`.

@include 'tokenfields.mdx'

### Sample request

```shell-session
$ curl \
    --header "X-Vault-Token: ..." \
    --request POST \
    --data @payload.json \
    http://127.0.0.1:8200/v1/auth/kerberos/config/ldap
```

### Sample payload

```json
{
  "binddn": "cn=vault,ou=Users,dc=example,dc=com",
  "deny_null_bind": true,
  "discoverdn": false,
  "groupattr": "cn",
  "groupdn": "ou=Groups,dc=example,dc=com",
  "groupfilter": "(\u0026(objectClass=group)(member:1.2.840.113556.1.4.1941:={{.UserDN}}))",
  "insecure_tls": false,
  "starttls": false,
  "tls_max_version": "tls12",
  "tls_min_version": "tls12",
  "url": "ldaps://ldap.myorg.com:636",
  "userattr": "samaccountname",
  "userdn": "ou=Users,dc=example,dc=com"
}
```

## Read Kerberos LDAP configuration

This endpoint retrieves the LDAP configuration for the Kerberos auth method.

| Method | Path                         |
| :----- | :--------------------------- |
| `GET`  | `/auth/kerberos/config/ldap` |

### Sample request

```shell-session
$ curl \
    --header "X-Vault-Token: ..." \
    http://127.0.0.1:8200/v1/auth/kerberos/config/ldap
```

### Sample response

```json
{
  "auth": null,
  "warnings": null,
  "wrap_info": null,
  "data": {
    "binddn": "cn=vault,ou=Users,dc=example,dc=com",
    "bindpass": "",
    "certificate": "",
    "deny_null_bind": true,
    "discoverdn": false,
    "groupattr": "cn",
    "groupdn": "ou=Groups,dc=example,dc=com",
    "groupfilter": "(\u0026(objectClass=group)(member:1.2.840.113556.1.4.1941:={{.UserDN}}))",
    "insecure_tls": false,
    "starttls": false,
    "tls_max_version": "tls12",
    "tls_min_version": "tls12",
    "upndomain": "",
    "url": "ldaps://ldap.myorg.com:636",
    "userattr": "samaccountname",
    "userdn": "ou=Users,dc=example,dc=com"
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}
```

## List Kerberos LDAP groups

This endpoint returns a list of existing LDAP groups in the Kerberos auth method.

| Method | Path                    |
| :----- | :---------------------- |
| `LIST` | `/auth/kerberos/groups` |

### Sample request

```shell-session
$ curl \
    --header "X-Vault-Token: ..." \
    --request LIST \
    http://127.0.0.1:8200/v1/auth/kerberos/groups
```

### Sample response

```json
{
  "auth": null,
  "warnings": null,
  "wrap_info": null,
  "data": {
    "keys": ["scientists", "engineers"]
  },
  "lease_duration": 0,
  "renewable": false,
  "lease_id": ""
}
```

## Read Kerberos LDAP group

This endpoint returns the policies associated with a Kerberos LDAP group.

| Method | Path                          |
| :----- | :---------------------------- |
| `GET`  | `/auth/kerberos/groups/:name` |

### Parameters

- `name` `(string: <required>)` – The name of the LDAP group.

### Sample request

```shell-session
$ curl \
    --header "X-Vault-Token: ..." \
    http://127.0.0.1:8200/v1/auth/kerberos/groups/admins
```

### Sample response

```json
{
  "data": {
    "policies": ["admin", "default"]
  },
  "renewable": false,
  "lease_id": "",
  "lease_duration": 0,
  "warnings": null
}
```

## Create/Update Kerberos LDAP group

This endpoint creates or updates LDAP group policies.

| Method | Path                          |
| :----- | :---------------------------- |
| `POST` | `/auth/kerberos/groups/:name` |

### Parameters

- `name` `(string: <required>)` – The name of the LDAP group.
- `policies` `(string: "")` – Comma-separated list of policies associated to the
  group.

### Sample payload

```json
{
  "policies": "admin,default"
}
```

### Sample request

```shell-session
$ curl \
    --header "X-Vault-Token: ..." \
    --request POST \
    --data @payload.json \
    http://127.0.0.1:8200/v1/auth/kerberos/groups/admins
```

## Delete Kerberos LDAP group

This endpoint deletes the LDAP group and policy association.

| Method   | Path                          |
| :------- | :---------------------------- |
| `DELETE` | `/auth/kerberos/groups/:name` |

### Parameters

- `name` `(string: <required>)` – The name of the LDAP group.

### Sample request

```shell-session
$ curl \
    --header "X-Vault-Token: ..." \
    --request DELETE \
    http://127.0.0.1:8200/v1/auth/kerberos/groups/admins
```

## Login with Kerberos

This endpoint allows you to log in with a valid Kerberos SPNEGO
token. This token is obtained by the client, marshalled, and
converted to base 64 using standard encoding.

Example SPNEGO token (newlines added for readability):

```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```

| Method | Path                   |
| :----- | :--------------------- |
| `POST` | `/auth/kerberos/login` |

### Sample request

```shell-session
$ curl \
    --header "Authorization: Negotiate YIIFSw...sWw" \
    --request POST \
    http://127.0.0.1:8200/v1/auth/kerberos/login
```