SSH Authentication with Azure Active Directory (AD)

This guide will cover how to configure Microsoft Azure Active Directory to issue SSH credentials to specific groups of users with a SAML Authentication Connector. When used in combination with role-based access control (RBAC), it allows SSH administrators to define policies like:

• Only members of the "DBA" Azure AD group can SSH into machines running PostgreSQL.
• Developers must never SSH into production servers.

The following steps configure an example SAML authentication connector matching Azure AD groups with security roles. You can choose to configure other options.

Prerequisites

Before you get started you’ll need:

• An Azure AD admin account with access to creating non-gallery applications (P2 License)
• To register one or more users in the directory
• To create at least two security groups in Azure AD and assign one or more users to each group
• Teleport role with access to maintaining saml resources. This is available in the default editor role.

tsh login --proxy=teleport.example.com [email protected]
tctl status
Cluster  teleport.example.com
Version  12.1.1
CA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

tsh login --proxy=myinstance.teleport.sh [email protected]
tctl status
Cluster  myinstance.teleport.sh
Version  12.1.1
CA pin   sha256:sha-hash-here

Enable default SAML authentication

Configure Teleport to use SAML authentication as the default instead of the local user database.

You can either edit your Teleport configuration file or create a dynamic resource.

auth_service:
  authentication:
    type: saml

Configure Azure AD

1. Select Azure AD -> Enterprise Applications

   

2. Select New application

   

3. Select a Non-gallery application

   

4. Enter the display name (e.g, Teleport)

   

5. Select Properties under Manage and set User assignment required? to No

6. Select Single sign-on under Manage and choose SAML

   

7. Edit the Basic SAML Configuration

   

8. For Entity ID and Reply URL, enter the same proxy URL.

   For self-hosted deployments, the URL will be similar to https://teleport.example.com:3080/v1/webapi/saml/acs/connectorName.

   For Teleport Cloud users, the URL will be similar to https://mytenant.teleport.sh.

   

9. Edit User Attributes & Claims

   • Edit the claim name.
   • Change the name identifier format to Default. Make sure the source attribute is user.userprincipalname.
   
   • Add a group claim to make user security groups available to the connector
   
   • Add a claim that transforms an Azure AD username in order to pass it to Teleport.
   

10. In SAML Signing Certificate, click the link to download the Federation Metadata XML.

    

Create a SAML Connector

Now, create a SAML connector resource. Write the following to azure-connector.yaml:

kind: saml
version: v2
metadata:
  # the name of the connector
  name: azure-saml
spec:
  display: "Microsoft"

  # enables/disables idp-initiated saml login
  allow_idp_initiated: false

  # acs is the Assertion Consumer Service URL. This should be the address of
  # the Teleport proxy that your identity provider will communicate with.
  # The last segment of the URL must be identical to the connector metadata name.
  acs: https://teleport.example.com:3080/v1/webapi/saml/acs/azure-saml
  attributes_to_roles:
    - {name: "http://schemas.microsoft.com/ws/2008/06/identity/claims/groups", value: "<group id 930210...>", roles: ["editor"]}
    - {name: "http://schemas.microsoft.com/ws/2008/06/identity/claims/groups", value: "<group id 93b110...>", roles: ["dev"]}
  # Populate entity_descriptor with the federator data xml or set entity_descriptor_url to automatically load from the SSO
  entity_descriptor: |
    <federationmedata.xml contents>

Replace the acs field with your Teleport address, update the group IDs in the attributes_to_roles field with the actual Azure AD group ID values, and insert the downloaded Federation Metadata XML into the entity_descriptor field.

Create the connector using tctl:

tctl create azure-connector.yaml

Automatic signing key pair

Teleport will generate a signing key pair and update the SAML connector with the signing_key_pair property.

Alternatively, you can generate your own keypair when creating a connector using openssl:

openssl req  -nodes -new -x509  -keyout server.key -out server.cer

Create a new Teleport role

Create a Teleport role resource that will use external username data from the Azure AD connector to determine which Linux logins to allow on a host.

Users with the following dev role are only allowed to log in to nodes with the access: relaxed Teleport label. They can log in as either ubuntu or a username that arrives via the Azure AD connector. Users with this role cannot obtain admin access to Teleport.

kind: role
version: v5
metadata:
  name: dev
spec:
  options:
    max_session_ttl: 24h
  allow:
    logins: [ "{{external.username}}", ubuntu ]
    node_labels:
      access: relaxed

Replace ubuntu with the Linux login available on your servers.

tctl create dev.yaml

Testing

The CLI is the same as before:

tsh --proxy=proxy.example.com login

This command will print the SSO login URL and will try to open it automatically in a browser.

Token encryption

Azure AD's SAML token encryption encrypts the SAML assertions sent to Teleport during SSO redirect.

Set up Teleport token encryption

Start with generating a public/private key and a certificate. You will set up the public certificate with Azure AD and the private key with Teleport.

openssl req  -nodes -new -x509  -keyout server.key -out server.cer

If you are modifying the existing connector, write the YAML to a file first:

tctl get saml --with-secrets > azure-out.yaml

You will notice that Teleport has generated a signing_key_pair. This key pair is used to sign responses.

kind: saml
metadata:
  name: azure-saml
spec:
  acs: https://teleport.example.com/v1/webapi/saml/acs/azure-saml
  attributes_to_roles:
  - name: http://schemas.microsoft.com/ws/2008/06/identity/claims/groups
    roles:
    - editor
    - access
    - auditor
    value: '*'
  audience: https://teleport.example.com/v1/webapi/saml/acs/azure-saml
  cert: ""
  display: Microsoft
  entity_descriptor: |
    <?xml ...
  entity_descriptor_url: ""
  issuer: https://sts.windows.net/your-id-here/
  service_provider_issuer: https://teleport.example.com/v1/webapi/saml/acs/azure-saml
  signing_key_pair:
    cert: |
      -----BEGIN CERTIFICATE-----
      ...
      -----END CERTIFICATE-----
    private_key: |
      -----BEGIN RSA PRIVATE KEY-----
      ...
      -----END RSA PRIVATE KEY-----
  sso: https://login.microsoftonline.com/your-id-here/saml2
version: v2

Add assertion_key_pair using the data from server.key and server.cer.

kind: saml
metadata:
  name: azure-saml
spec:
  acs: https://teleport.example.com/v1/webapi/saml/acs/azure-saml
  attributes_to_roles:
  - name: http://schemas.microsoft.com/ws/2008/06/identity/claims/groups
    roles:
    - editor
    - access
    - auditor
    value: '*'
  audience: https://teleport.example.com/v1/webapi/saml/acs/azure-saml
  cert: ""
  display: Microsoft
  entity_descriptor: |
    <?xml ...
  entity_descriptor_url: ""
  issuer: https://sts.windows.net/your-id-here/
  service_provider_issuer: https://teleport.example.com/v1/webapi/saml/acs/azure-saml
  signing_key_pair:
    cert: |
      -----BEGIN CERTIFICATE-----
      ...
      -----END CERTIFICATE-----
    private_key: |
      -----BEGIN RSA PRIVATE KEY-----
      ...
      -----END RSA PRIVATE KEY-----
  sso: https://login.microsoftonline.com/your-id-here/saml2
version: v2

After your edits, the file will look like this:

kind: saml
metadata:
  name: azure-saml
spec:
  acs: https://teleport.example.com/v1/webapi/saml/acs/azure-saml
  attributes_to_roles:
  - name: http://schemas.microsoft.com/ws/2008/06/identity/claims/groups
    roles:
    - editor
    - access
    - auditor
    value: '*'
  audience: https://teleport.example.com/v1/webapi/saml/acs/azure-saml
  cert: ""
  display: Microsoft
  entity_descriptor: |
    <?xml ...
  entity_descriptor_url: ""
  issuer: https://sts.windows.net/your-id-here/
  service_provider_issuer: https://teleport.example.com/v1/webapi/saml/acs/azure-saml
  assertion_key_pair:
    cert: |
      -----BEGIN CERTIFICATE-----
      New CERT
      -----END CERTIFICATE-----
    private_key: |
      -----BEGIN RSA PRIVATE KEY-----
      New private key
      -----END RSA PRIVATE KEY-----
  signing_key_pair:
    cert: |
      -----BEGIN CERTIFICATE-----
      ...
      -----END CERTIFICATE-----
    private_key: |
      -----BEGIN RSA PRIVATE KEY-----
      ...
      -----END RSA PRIVATE KEY-----
  sso: https://login.microsoftonline.com/your-id-here/saml2
version: v2

Update the connector:

tctl create -f azure-out.yaml

Activate token encryption

• Navigate to Token Encryption

• Import certificate

• Activate it

If the SSO login with this connector is successful, the encryption works.

Troubleshooting

Troubleshooting SSO configuration can be challenging. Usually a Teleport administrator must be able to:

• Ensure that HTTP/TLS certificates are configured properly for both Teleport proxy and the SSO provider.

• Be able to see what SAML/OIDC claims and values are getting exported and passed by the SSO provider to Teleport.
• Be able to see how Teleport maps the received claims to role mappings as defined in the connector.

If something is not working, we recommend to:

• Double-check the host names, tokens and TCP ports in a connector definition.

Using the Web UI

If you get "access denied" or other login errors, the number one place to check is the Audit Log. You can access it in the Activity tab of the Teleport Web UI.

Example of a user being denied because the role clusteradmin wasn't set up:

{
  "code": "T1001W",
  "error": "role clusteradmin is not found",
  "event": "user.login",
  "method": "oidc",
  "success": false,
  "time": "2019-06-15T19:38:07Z",
  "uid": "cd9e45d0-b68c-43c3-87cf-73c4e0ec37e9"
}

Teleport does not show the expected Nodes

When Teleport's Auth Service receives a request to list Teleport Nodes (e.g., to display Nodes in the Web UI or via tsh ls), it only returns the Nodes that the current user is authorized to view.

For each Node in the user's Teleport cluster, the Auth Service applies the following checks in order and, if one check fails, hides the Node from the user:

• None of the user's roles contain a deny rule that matches the Node's labels.
• At least one of the user's roles contains an allow rule that matches the Node's labels.

If you are not seeing Nodes when expected, make sure that your user's roles include the appropriate allow and deny rules as documented in the Teleport Access Controls Reference.

When configuring SSO, ensure that the identity provider is populating each user's traits correctly. For a user to see a Node in Teleport, the result of populating a template variable in a role's allow.logins must match at least one of a user's traits.logins.

In this example a user will have usernames ubuntu, debian and usernames from the SSO trait logins for Nodes that have a env: dev label. If the SSO trait username is bob then the usernames would include ubuntu, debian, and bob.

kind: role
metadata:
  name: example-role
spec:
  allow:
    logins: ['{{external.logins}}', ubuntu, debian]
    node_labels:
      'env': 'dev'
version: v5

Failed to process SAML callback

If you encounter a "Failed to process SAML callback" error, take a look at the audit log.

Special characters are not allowed in resource names, please use name composed only from characters,
hyphens and dots: /web/users/ops_example.com#EXT#@opsexample.onmicrosoft.com/params

The error above is caused by a Name ID format that is not compatible with Teleport's naming conventions.

Change the Name ID format to use email instead:

Further reading

• Teleport Configuration Resources Reference