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Introducing Device Trust
Introducing Device Trust

Length: 01:35

Version: 15.x

Getting Started with Device Trust

note

Device Trust supports the following components:

  • User devices: macOS, Windows and Linux.
  • Teleport client: tsh and Teleport connect.
  • Resources: Apps (role-based enforcement only), SSH nodes, databases, and Kubernetes clusters

Support for the Web UI and desktop access are planned for upcoming Teleport versions.

Device Trust requires two of the following steps to have been configured:

  • Device enforcement mode configured via either a role or a cluster-wide config.
  • Trusted device registered and enrolled with Teleport.

In this guide, you will update an existing user profile to assign the preset require-trusted-device role and then enroll a trusted device into Teleport to access a resource (a test linux server) protected with Teleport.

Prerequisites​

  • To enroll a macOS device, you need:
  • To enroll a Windows device, you need:
  • To enroll a Linux device, you need:
    • A device with TPM 2.0.
    • A user with permissions to use the /dev/tpmrm0 device (typically done by assigning the tss group to the user).
    • tsh v15.0.0 or newer. Install tsh for Linux.
  • User with editor role. 
    $ tsh status
    > Profile URL:      teleport.example.com:443
    Logged in as:       myuser
    Cluster:            teleport.example.com
    Roles:              access, auditor, editor
    Logins:             root, ubuntu, ec2-user
    Kubernetes:         disabled
    Valid until:        2023-08-22 03:30:24 -0400 EDT [valid for 11h52m0s]
    Extensions:         login-ip, permit-agent-forwarding, permit-port-forwarding, permit-pty, private-key-policy
  • Access to a linux server (any Linux server you can access via tsh ssh will do). 
    $ tsh ls
    Node Name        Address        Labels
    ---------------- -------------- --------------------------------------
    ip-172-31-35-170 ⟵ Tunnel

    # test connection to ip-172-31-35-170
    $ tsh ssh root@ip-172-31-35-170
    root@ip-172-31-35-170:~#

Once the above prerequisites are met, begin with the following step.

Step 1/2. Update user profile to enforce Device Trust​

To enforce Device Trust, a user must be assigned with a role with Device Trust mode "required".

For this guide, we will use the preset require-trusted-device role to update current user profile.

v13.3.5 and Below

The preset require-trusted-device role, as referenced in this guide, is only available from Teleport version 13.3.6 and above. For older Teleport cluster, you will need to update a role with device_trust_mode: required.

Update a role to enforce Device Trust

For simplicity, the example below updates the preset access role but you can update any existing access granting role which the user is assigned with to enforce Device Trust.

First, fetch a role so you can update it locally:

$ tctl edit role/access

Edit the role with device trust mode:

kind: role
metadata:
  labels:
    teleport.internal/resource-type: preset
  name: access
spec:
  allow:
    logins:
    - '{{internal.logins}}'
    ...
  options:
    # require authenticated device check for this role
+   device_trust_mode: "required" # add this line
    ...
  deny:
    ...

Save your edits.

Now that the access role is configured with device mode "required", users with this role will be enforced with Device Trust.

First, let's fetch the user profile locally so we can update it with the preset require-trusted-device role.

$ tctl get users/myuser > myuser.yaml

Edit the profile:

kind: user
metadata:
  id: 1692716146877042322
  name: myuser
spec:
  created_by:
    time: "2023-08-14T13:42:22.291972449Z"
  expires: "0001-01-01T00:00:00Z"
  roles:
  - access
  - auditor
  - editor
+ - require-trusted-device # add this line
  status:
    is_locked: false
  ...

Save and update user:

$ tctl create -f myuser.yaml

Now that the user profile is updated to enforce Device Trust, try to access the test server again.

$ tsh logout; tsh login --proxy=teleport.example.com --user=myuser
$ tsh ssh root@ip-172-31-35-170
ERROR: access denied to root connecting to ip-172-31-35-170:0

As you can verify from the above step, access to ip-172-31-35-170 ssh server, which was previously accessible, is now forbidden.

Step 2/2. Enroll device​

To access ip-172-31-35-170 server again, you will have to enroll your device.

Enrolling your device is easy, and can be done using tsh client:

$ tsh device enroll --current-device
Device "C00AA0AAAA0A"/macOS registered and enrolled
self enrollment: v13.3.5+

The --current-device flag tells tsh to enroll current device. User must have the preset editor or device-admin role to be able to self-enroll their device. For users without the editor or device-admin roles, an enrollment token must be generated by a device admin, which can then be used to enroll the device. Learn more about manual device enrollment in the device management guide

Relogin to fetch updated certificate with device extension:

$ tsh logout; tsh login --proxy=teleport.example.com --user=myuser

$ tsh status
> Profile URL:        teleport.example.com:443
  Logged in as:       myuser
  Cluster:            teleport.example.com:443
  Roles:              access, auditor, editor
  Logins:             root
  Kubernetes:         enabled
  Valid until:        2023-08-22 04:06:53 -0400 EDT [valid for 12h0m0s]
  Extensions:         login-ip, ... teleport-device-asset-tag, teleport-device-credential-id, teleport-device-id

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

Now, let's try to access server (ip-172-31-35-170) again:

$ tsh ssh root@ip-172-31-35-170
root@ip-172-31-35-170:~#

Congratulations! You have successfully configured a Trusted Device and accessed a resource protected with Device Trust enforcement.

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.

"Failed to open the TPM device" on Linux​

Linux users need permissions to read and write from the TPM device, /dev/tpmrm0. Without such permissions tsh would need sudo prompts for most operations.

The simplest way to solve this is to check if your distro ships with the tss group and assign it to your OS user. If that is not possible, or you are looking for a different solution, we recommend creating udev rules similar to the ones shipped by the TPM2 Software Stack.

Auto enrollment not working​

Auto-enrollment ceremonies, due to their automated nature, are stricter than regular enrollment. Additional auto-enrollment checks include:

  1. Verifying device profile data, such as data originated from Jamf, against the actual device
  2. Verifying that the device is not enrolled by another user (auto-enroll cannot take devices that are already enrolled)

Check you audit log for clues: look for failed "Device Enroll Token Created" events and see the "message" field in the details (auto-enroll audit log details available since Teleport v15.4.21).

If you suspect (1) is the issue, compare the actual device against its inventory definition (tsh device collect executed in the actual device vs tctl get device/<asset_tag>). Tweaking the device profile, manual enrollment or waiting for the next MDM sync may solve the issue.

If you suspect (2), you can unenroll the device using tctl edit device/<asset_tag> and changing the "enroll_status" field to "not_enrolled".

App access and "access to this app requires a trusted device"​

A Teleport admin configured the particular app you are trying to access to require a trusted device.

There are a few situations that might cause the error:

  1. You are trying to access the app using the Web UI.

  2. You are trying to access the app using an untrusted device.

The Web UI is currently not capable of device authentication. To access apps protected by device trust you need to use one of the tsh commands described by App Access support. For example, for an app called myapp, run tsh proxy app myapp -p 8888, then open http://localhost:8888 in your browser.

If you are already running tsh proxy app, or using the certificates acquired from tsh app login, then it's likely your device isn't registered or enrolled. In this case, follow the advice from the unauthorized device section above.

Next steps​