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Dual Authorization

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Teleport Role-based access request

Teleport Role-based access request

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You can set up Teleport to require the approval of multiple team members to perform some critical actions. Here are the most common scenarios:

  • Improve the security of your system and prevent one successful phishing attack from compromising your system.
  • Satisfy FedRAMP AC-3 Dual authorization control that requires approval of two authorized individuals.

In this guide, we will set up Teleport's Just-in-Time Access Requests to require the approval of two team members for a privileged role dbadmin.

This guide requires a commercial edition of Teleport. The open source edition of Teleport only supports GitHub as an SSO provider.

Note

The steps below describe how to use Teleport with Mattermost. You can also integrate with many other providers.

Prerequisites

  • Mattermost installed.
  • A running Teleport cluster, including the Auth Service and Proxy Service. For details on how to set this up, see our Enterprise Getting Started guide.

  • The tctl admin tool and tsh client tool version >= 11.0.3, which you can download by visiting the customer portal.

    tctl version

    Teleport v11.0.3 go1.19

    tsh version

    Teleport v11.0.3 go1.19

  • A Teleport Cloud account, which includes a running Auth Service and Proxy Service. If you do not have a Teleport Cloud account, visit the sign up page to begin your free trial.

  • The tctl admin tool and tsh client tool version >= 10.3.8. To download these tools, visit the Downloads page.

    tctl version

    Teleport v10.3.8 go1.19

    tsh version

    Teleport v10.3.8 go1.19

Running Mattermost locally with Docker
docker run --name mattermost-preview -d --publish 8065:8065 --add-host dockerhost:127.0.0.1 mattermost/mattermost-preview

To connect to Teleport, log in to your cluster using tsh, then use tctl remotely:

tsh login --proxy=teleport.example.com [email protected]
tctl status

Cluster teleport.example.com

Version 11.0.3

CA pin sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

You can run subsequent tctl commands in this guide on your local machine.

For full privileges, you can also run tctl commands on your Auth Service host.

To connect to Teleport, log in to your cluster using tsh, then use tctl remotely:

tsh login --proxy=myinstance.teleport.sh [email protected]
tctl status

Cluster myinstance.teleport.sh

Version 10.3.8

CA pin sha256:sha-hash-here

You must run subsequent tctl commands in this guide on your local machine.

Step 1/3. Set up a Teleport bot

Create a bot within Mattermost

Enable bot account creation in "System Console -> Integrations".

Toggle Enable Bot Account Creation.

Enable bots

Go back to your team settings, navigate to "Integrations -> Bot Accounts". Press "Add Bot Account".

Enable bots

Add the "Post All" permission on the new account.

Enable bots

Create the bot and save the access token.

Set up RBAC for the plugin

Teleport's Access Request plugins authenticate to your Teleport cluster as a user with permissions to list and read Access Requests. This way, plugins can retrieve Access Requests from the Teleport Auth Service and present them to reviewers.

Define a user and role called access-plugin by adding the following content to a file called access-plugin.yaml:

kind: role
version: v5
metadata:
  name: access-plugin
spec:
  allow:
    rules:
      - resources: ['access_request']
        verbs: ['list', 'read']
      - resources: ['access_plugin_data']
        verbs: ['update']
---
kind: user
metadata:
  name: access-plugin
spec:
  roles: ['access-plugin']
version: v2

Create the user and role:

tctl create -f access-plugin.yaml

As with all Teleport users, the Teleport Auth Service authenticates the access-plugin user by issuing short-lived TLS credentials. In this case, we will need to request the credentials manually by impersonating the access-plugin role and user.

If you are using tctl from the Auth Service host, you will already have impersonation privileges.

To grant your user impersonation privileges for access-plugin, define a role called access-plugin-impersonator by pasting the following YAML document into a file called access-plugin-impersonator.yaml:

kind: role
version: v5
metadata:
  name: access-plugin-impersonator
spec:
  allow:
    impersonate:
      roles:
      - access-plugin
      users:
      - access-plugin

Create the access-plugin-impersonator role:

tctl create -f access-plugin-impersonator.yaml

Retrieve your user definition:

TELEPORT_USER=$(tsh status --format=json | jq -r .active.username)
tctl get users/${TELEPORT_USER?} > myuser.yaml

Edit myuser.yaml to include the role you just created:

  roles:
   - access
   - auditor
   - editor
+  - access-plugin-impersonator

Apply your changes:

tctl create -f myuser.yaml

Log out of your Teleport cluster and log in again. You will now be able to generate signed certificates for the access-plugin role and user.

Export the access-plugin identity files

Like all Teleport users, access-plugin needs signed credentials in order to connect to your Teleport cluster. You will use the tctl auth sign command to request these credentials for your plugin.

The format of the credentials depends on whether you have set up your network to give the plugin direct access to the Teleport Auth Service, or if all Teleport clients and services connect to the Teleport Proxy Service instead.

Environment type

The following tctl auth sign command impersonates the access-plugin user, generates signed credentials, and writes an identity file to the local directory:

tctl auth sign --user=access-plugin --out=auth.pem

Teleport's Access Request plugins listen for new and updated Access Requests by connecting to the Teleport Auth Service's gRPC endpoint over TLS.

The identity file, auth.pem, includes both TLS and SSH credentials. Your Access Request plugin uses the SSH credentials to connect to the Proxy Service, which establishes a reverse tunnel connection to the Auth Service. The plugin uses this reverse tunnel, along with your TLS credentials, to connect to the Auth Service's gRPC endpoint.

You will refer to this file later when configuring the plugin.

If your network allows your plugin to access the Auth Service directly, e.g., you are running the plugin on the Auth Service host, the plugin uses TLS credentials to connect to the Auth Service's gRPC endpoint and listen for new and updated Access Requests.

You can generate TLS credentials with the following command:

tctl auth sign --format=tls --user=access-plugin --out=auth

This command should result in three PEM-encoded files: auth.crt, auth.key, and auth.cas (certificate, private key, and CA certs respectively). Later, you will configure the plugin to use these credentials to connect to the Auth Service directly.

The following tctl auth sign command impersonates the access-plugin user, generates signed credentials, and writes an identity file to the local directory:

tctl auth sign --user=access-plugin --out=auth

Then create a Kubernetes secret:

kubectl create secret generic teleport-mattermost-identity --from-file=auth_id=auth.pem

Teleport's Access Request plugins listen for new and updated Access Requests by connecting to the Teleport Auth Service's gRPC endpoint over TLS.

The identity file, auth.pem, includes both TLS and SSH credentials. Your Access Request plugin uses the SSH credentials to connect to the Proxy Service, which establishes a reverse tunnel connection to the Auth Service. The plugin uses this reverse tunnel, along with your TLS credentials, to connect to the Auth Service's gRPC endpoint.

You will refer to this file later when configuring the plugin.

The following tctl auth sign command impersonates the access-plugin user, generates signed credentials, and writes an identity file to the local directory:

tctl auth sign --user=access-plugin --out=auth

Then create a Kubernetes secret:

kubectl create secret generic teleport-mattermost-identity --from-file=auth_id=auth.pem

Teleport's Access Request plugins listen for new and updated Access Requests by connecting to the Teleport Auth Service's gRPC endpoint over TLS.

The identity file, auth.pem, includes both TLS and SSH credentials. Your Access Request plugin uses the SSH credentials to connect to the Proxy Service, which establishes a reverse tunnel connection to the Auth Service. The plugin uses this reverse tunnel, along with your TLS credentials, to connect to the Auth Service's gRPC endpoint.

The Helm chart only supports the file format.

You will refer to this file later when configuring the plugin.

Certificate Lifetime

By default, tctl auth sign produces certificates with a relatively short lifetime. For production deployments, you can use the --ttl flag to ensure a more practical certificate lifetime, e.g., --ttl=8760h to export a one-year certificate.

We'll reference the exported file(s) later when configuring the plugin.

Install the plugin

curl -L https://get.gravitational.com/teleport-access-mattermost-v11.0.3-linux-amd64-bin.tar.gz
tar -xzf teleport-access-mattermost-v11.0.3-linux-amd64-bin.tar.gz
cd teleport-access-mattermost
./install

To install from source you need git and go >= 1.19 installed.

Checkout teleport-plugins

git clone https://github.com/gravitational/teleport-plugins.git
cd teleport-plugins/access/mattermost
make
teleport-mattermost configure > /etc/teleport-mattermost.toml

Update the config with the Teleport address, Mattermost URL, and a bot token.

# example mattermost configuration TOML file
[teleport]
auth_server = "example.com:3025"                             # Teleport Auth Server GRPC API address
client_key = "/var/lib/teleport/plugins/mattermost/auth.key" # Teleport GRPC client secret key
client_crt = "/var/lib/teleport/plugins/mattermost/auth.crt" # Teleport GRPC client certificate
root_cas = "/var/lib/teleport/plugins/mattermost/auth.cas"   # Teleport cluster CA certs

[mattermost]
url = "https://mattermost.example.com" # Mattermost Server URL
team = "team-name"                     # Mattermost team in which the channel resides.
channel = "channel-name"               # Mattermost Channel name to post requests to
token = "api-token"                    # Mattermost Bot OAuth token
secret = "signing-secret-value"        # Mattermost API signing Secret

[http]
public_addr = "example.com" # URL on which callback server is accessible externally, e.g. [https://]teleport-mattermost.example.com
# listen_addr = ":8081" # Network address in format [addr]:port on which callback server listens, e.g. 0.0.0.0:443
https_key_file = "/var/lib/teleport/plugins/mattermost/server.key"  # TLS private key
https_cert_file = "/var/lib/teleport/plugins/mattermost/server.crt" # TLS certificate

[log]
output = "stderr" # Logger output. Could be "stdout", "stderr" or "/var/lib/teleport/mattermost.log"
severity = "INFO" # Logger severity. Could be "INFO", "ERROR", "DEBUG" or "WARN".

# example mattermost configuration TOML file
[teleport]
auth_server = "myinstance.teleport.sh:443"                   # Teleport Cloud proxy HTTPS address
identity = "/var/lib/teleport/plugins/mattermost/auth.pem"   # Identity file path

[mattermost]
url = "https://mattermost.example.com" # Mattermost Server URL
team = "team-name"                     # Mattermost team in which the channel resides.
channel = "channel-name"               # Mattermost Channel name to post requests to
token = "api-token"                    # Mattermost Bot OAuth token
secret = "signing-secret-value"        # Mattermost API signing Secret

[http]
public_addr = "example.com" # URL on which callback server is accessible externally, e.g. [https://]teleport-mattermost.example.com
# listen_addr = ":8081" # Network address in format [addr]:port on which callback server listens, e.g. 0.0.0.0:443
https_key_file = "/var/lib/teleport/plugins/mattermost/server.key"  # TLS private key
https_cert_file = "/var/lib/teleport/plugins/mattermost/server.crt" # TLS certificate

[log]
output = "stderr" # Logger output. Could be "stdout", "stderr" or "/var/lib/teleport/mattermost.log"
severity = "INFO" # Logger severity. Could be "INFO", "ERROR", "DEBUG" or "WARN".

Step 2/3. Configure dual authorization

In this section, we will use an example to show you how to require dual authorization for a user to assume a role.

Require dual authorization for a role

Alice and Ivan are reviewers. They can approve requests for assuming role dbadmin. Bob is a DevOps engineer and can assume the dbadmin role if two members of the reviewer role approve the request.

Create the following dbadmin, reviewer and devops roles:

kind: role
version: v5
metadata:
  name: reviewer
spec:
  allow:
    review_requests:
      roles: ['dbadmin']
---
kind: role
version: v5
metadata:
  name: devops
spec:
  allow:
    request:
      roles: ['dbadmin']
      thresholds:
        - approve: 2
          deny: 1
---
kind: role
version: v5
metadata:
  name: dbadmin
spec:
  allow:
    logins: ['root']
    node_labels:
      'env': 'prod'
      'type': 'db'

The commands below create the local users Bob, Alice, and Ivan.

tctl users add [email protected] --roles=devops
tctl users add [email protected] --roles=reviewer
tctl users add [email protected] --roles=reviewer

Create an Access Request

Bob does not have a role dbadmin assigned to him, but can create an Access Request for it.

Bob can create an Access Request for the dbadmin role in the Web UI or CLI:

Mattermost-Request

Bob has to set valid emails of Alice and Ivan matching in Mattermost.

tsh request create --roles=dbadmin [email protected],[email protected]

Chatbot will notify both Alice and Ivan:

Mattermost-Request

Alice and Ivan can review and approve request using Web UI or CLI:

Teleport-Approve

tsh request list

ID User Roles Created (UTC) Status

------------------------------------ --------------- ------- ------------------- -------

9c721e54-b049-4ef8-a7f6-c777aa066764 [email protected] dbadmin 03 Apr 21 03:58 UTC PENDING

tsh request review --approve --reason="hello" 9c721e54-b049-4ef8-a7f6-c777aa066764

Successfully submitted review. Request state: APPROVED

If Bob has created a request using CLI, he will assume it once it has been approved. Bob can also assume granted Access Request roles using Web UI:

Teleport Assume

Troubleshooting

Cert errors in self-hosted deployments

You may be getting certificate errors if Teleport's Auth Service is missing an address in the server certificate:

authentication handshake failed: x509: cannot validate certificate for 127.0.0.1 because it doesn't contain any IP SANs
x509: certificate is valid for,*.teleport.cluster.local, teleport.cluster.local, not example.com

To fix the problem, update the Auth Service with a public address, and restart Teleport:

auth_service:
  public_addr: ['localhost:3025', 'example.com:3025']