Manage Trusted Devices

Prerequisites

• To enroll a macOS device, you need:
  • A signed and notarized tsh binary for enrollment. Download the macOS tsh installer.
  • A Teleport version newer than v12.0.0.
• To enroll a Windows device, you need:
  • A device that includes a TPM with 2.0 support.
  • tsh installed on the device. Download the Windows tsh installer.
  • Credentials for a user with administrator privileges for the device. This is only required during enrollment.
  • A Teleport version newer than v13.1.2.

Register a trusted device

The tctl tool is used to manage the device inventory. A device admin is responsible for managing devices, adding new devices to the inventory and removing devices that are no longer in use.

tsh device enroll --current-device

Before you can enroll the device, you need to register it. To register a device, you first need to determine its serial number.

Retrieve device serial number with tsh (must be run on the device you want to register):

tsh device asset-tag
C00AA0AAAA0A

tsh device collect
DeviceCollectedData {  ...  "serial_number": "C00AA0AAAA0A",  ...}

Use the serial number to register device:

tctl devices add --os=macos --asset-tag="C00AA0AAAA0A"
Device C00AA0AAAA0A/macos added to the inventory

tctl devices ls
Asset Tag    OS    Enroll Status Device ID------------ ----- ------------- ------------------------------------C00AA0AAAA0A macOS not enrolled  9cdfc0ad-64b7-4d9c-this-is-an-example

tctl devices add --os=windows --asset-tag="C00AA0AAAA0A"
Device C00AA0AAAA0A/windows added to the inventory

tctl devices ls
Asset Tag    OS    Enroll Status Device ID------------ ----- ------------- ------------------------------------C00AA0AAAA0A windows not enrolled  9cdfc0ad-64b7-4d9c-this-is-an-example

Create a device enrollment token

A registered device becomes a trusted device after it goes through the enrollment ceremony. To enroll the device, a device enrollment token is necessary. The token is created by a device admin and sent to the person performing the enrollment off-band (for example, via a corporate chat).

To create an enrollment token run the command below, where --asset-tag is the serial number of the device we want to enroll:

tctl devices enroll --asset-tag="C00AA0AAAA0A"
Run the command below on device "C00AA0AAAA0A" to enroll it:tsh device enroll --token=AAAAAAAAAAAAAAAAAAAAAAAA-this-is-an-example

Enroll a trusted device

To perform the enrollment ceremony, using the device specified above, type the command printed by tctl devices enroll:

tsh device enroll --token=AAAAAAAAAAAAAAAAAAAAAAAA-this-is-an-example
Device "C00AA0AAAA0A"/macOS enrolled
tsh logout
tsh login --proxy=teleport.example.com --user=myuser # fetch new certificates
Enter password for Teleport user myuser:Tap any security keyDetected security key tap> Profile URL:        teleport.example.com:443  Logged in as:       myuser  Cluster:            teleport.example.com  Roles:              access, editor  Logins:             myuser  Kubernetes:         enabled  Valid until:        2023-06-23 02:47:05 -0300 -03 [valid for 12h0m0s]  Extensions:         teleport-device-asset-tag, teleport-device-credential-id, teleport-device-id

The presence of the teleport-device-* extensions shows that the device was successfully enrolled and authenticated. The device above is now a trusted device.

Auto-Enrollment

Distributing enrollment tokens to many users can be challenging. To address that, Teleport supports auto-enrollment. When enabled, auto-enrollment automatically enrolls the user's device in their next Teleport (tsh) login.

For auto-enrollment to work, the following conditions must be met:

• A device must be registered. Registration may be manual or performed using an integration, like the Jamf Pro integration.
• Auto-enrollment must be enabled in the cluster setting.
• User must have either preset editor or device-enroll (available v13.3.6+) role assigned to them.

Enable auto-enrollment in your cluster settings:

kind: cluster_auth_preference
version: v2
metadata:
  name: cluster-auth-preference
spec:
  # ...
  device_trust:
    mode: "required"
+   auto_enroll: true

auth_service:
  authentication:
    # ...
    device_trust:
+     auto_enroll: true

Once enabled, user's with their device registered in Teleport and with the required permission (preset editor or device-enroll role) will have their device enrolled to Teleport in their next login.

tsh logout
All users logged out.
tsh login --proxy=teleport.example.com --user=myuser
Enter password for Teleport user myuser:Tap any security keyDetected security key tap> Profile URL:        teleport.example.com:443  Logged in as:       myuser  Cluster:            teleport.example.com  Roles:              access, editor  Logins:             myuser  Kubernetes:         enabled  Valid until:        2023-06-23 02:47:05 -0300 -03 [valid for 12h0m0s]  Extensions:         teleport-device-asset-tag, teleport-device-credential-id, teleport-device-id

The presence of the teleport-device-* extensions shows that the device was successfully enrolled and authenticated.

Remove a trusted device

A device that is no longer in use may be removed using tctl devices rm --device-id=<ID> or tctl devices rm --asset-tag=<SERIAL>

First, find a device to delete:

tctl devices ls
Asset Tag    OS    Enroll Status Device ID------------ ----- ------------- ------------------------------------C00AA0AAAA0A macOS enrolled      c9cbb327-68a8-497e-b820-6a4b2bf58269

Now use asset-tag or device id to delete a device:

Delete using asset tag:
tctl devices rm --asset-tag=C00AA0AAAA0A
Device "C00AA0AAAA0A" removed
Delete using device id:
tctl devices rm --device-id=c9cbb327-68a8-497e-b820-6a4b2bf58269
Device "c9cbb327-68a8-497e-b820-6a4b2bf58269" removed

Dedicated device admin role

We recommend creating a dedicated device-admin role for device inventory management.

Following is an example of a role that grants permissions for the device resource is necessary to manage the inventory. Save the yaml below as device-admin.yaml and create it in your cluster:

version: v7
kind: role
metadata:
  name: device-admin
spec:
  allow:
    rules:
    - resources: ["device"]
      verbs:
      - create
      - read
      - list
      - update
      - delete
      - create_enroll_token
      - enroll

tctl create -f device-admin.yaml
role 'device-admin' has been created

Note that in addition to the usual CRUD verbs (create, read, list, update and delete), we have also included create_enroll_token and enroll. The create_enroll_token verb is necessary to execute the tctl devices enroll command; enroll is necessary to execute tsh device enroll.

Configuring a TPM EKCert CA allow-list

This advice only applies to Device Trust on platforms that use TPMs. For now, this is just Windows.

Some TPMs include a certificate—known as an EKCert—signed by the manufacturer's certificate authority (CA). This certificate allows a third party (such a Teleport cluster) to know that the TPM it is communicating with is legitimate. This significantly reduces the burden on the administrator to ensure that the device has not been tampered with prior to enrollment.

By default, the Teleport cluster does not verify the EKCert. This is because not all TPMs include an EKCert, and it is not possible to verify an EKCert without knowledge of the manufacturer's CA. This verification is enabled by the inclusion of the Teleport configuration field called ekcert_allowed_cas.

Once configured, only devices that include a TPM with an EKCert signed by a CA specified in the field will be able to enroll. Previously-enrolled devices will not be affected.

To configure ekcert_allowed_cas, you must first obtain the CA certificate in PEM format from the manufacturer of the TPM included in your devices. This step varies from manufacturer to manufacturer.

After you obtain the CA certificate in PEM format, there are two ways of configuring ekcert_allowed_cas:

• Statically using the Teleport configuration file. This is the simplest option, but is not possible for Teleport Cloud clusters and not recommended for clusters in a highly available configuration.
• Dynamically using cluster_auth_preference resource. This works with all clusters and is the most flexible.

kind: cluster_auth_preference
version: v2
metadata:
  name: cluster-auth-preference
spec:
  ...
  device_trust:
    mode: "required" # add this line
+    ekcert_allowed_cas:
+      # The CA is configured inline within the resource:
+      - |
+        -----BEGIN CERTIFICATE-----
+        --snip--
+        -----END CERTIFICATE-----

auth_service:
  authentication:
    ...
    device_trust:
+      ekcert_allowed_cas:
+      # The CA can be configured inline within the configuration file:
+      - |
+        -----BEGIN CERTIFICATE-----
+        --snip--
+        -----END CERTIFICATE-----
+      # Or, it can be configured in the configuration file using a path:
+      - /path/to/my/ekcert-ca.pem

Troubleshooting

"binary missing signature or entitlements" on tsh device enroll

A signed and notarized tsh binary is necessary to enroll and use a a trusted device. Download the macOS tsh installer to fix the problem.

"unauthorized device" errors using a trusted device

A trusted device needs to be registered and enrolled before it is recognized by Teleport as such. Follow the registration and enrollment steps and make sure to tsh logout and tsh login after enrollment is done.

Next steps

• Device Trust Enforcement
• Jamf Pro Integration