Monitor Teleport Audit Events with Splunk

Teleport's Event Handler plugin receives audit logs from the Teleport Auth Service and forwards them to your log management solution, letting you perform historical analysis, detect unusual behavior, and form a better understanding of how users interact with your Teleport cluster.

In this guide, we will show you how to configure the Teleport Event Handler plugin to send your Teleport audit logs to Splunk. In this setup, the Teleport Event Handler plugin forwards audit logs from Teleport to Splunk's Universal Forwarder, which stores them in Splunk Cloud Platform or Splunk Enterprise for visualization and alerting.

Prerequisites

• Splunk Cloud Platform or Splunk Enterprise v9.0.1 or above.

• A Linux host where you will run the Teleport Event Handler plugin and Splunk Universal Forwarder. The Universal Forwarder must be installed on the host.

  Running the Teleport Event Handler and Universal Forwarder on separate hosts

  If you run the Teleport Event Handler and Universal Forwarder on the same host, there is no need to open a port on the host for ingesting logs. However, if you run the Universal Forwarder on a separate host from the Teleport Event Handler, you will need to open a port on the Universal Forwarder host to traffic from the Teleport Event Handler. This guide assumes that the Universal Forwarder is listening on port 9061.

• On Splunk Enterprise, port 8088 should be open to traffic from the host running the Teleport Event Handler and Universal Forwarder.

tsh login --proxy=teleport.example.com [email protected]
tctl status
Cluster  teleport.example.com
Version  11.3.1
CA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

tsh login --proxy=myinstance.teleport.sh [email protected]
tctl status
Cluster  myinstance.teleport.sh
Version  11.2.1
CA pin   sha256:sha-hash-here

Step 1/4. Set up the Teleport Event Handler plugin

The Event Handler plugin is a binary that runs independently of your Teleport cluster. It authenticates to your Teleport cluster and your Splunk Universal Forwarder using mutual TLS. In this section, you will install the Teleport Event Handler plugin on the Linux host where you are running your Universal Forwarder and generate credentials that the plugin will use for authentication.

Install the Teleport Event Handler plugin

Follow the instructions for your environment to install the Teleport Event Handler plugin on your Universal Forwarder host:

curl -L -O https://get.gravitational.com/teleport-event-handler-v11.3.1-linux-amd64-bin.tar.gz
tar -zxvf teleport-event-handler-v11.3.1-linux-amd64-bin.tar.gz

docker pull public.ecr.aws/gravitational/teleport-plugin-event-handler:11.3.1

git clone https://github.com/gravitational/teleport-plugins.git --depth 1
cd teleport-plugins/event-handler/build.assets
make build

git clone https://github.com/gravitational/teleport-plugins.git --depth 1
cd teleport-plugins/event-handler
go build

Generate a starter config file

On the host where you are running the Universal Forwarder and the Teleport Event Handler plugin, execute the following command to generate a sample configuration that we will edit later:

teleport-event-handler configure . 

The teleport-event-handler configure command generates several files that you will refer to when generating credentials for the Teleport Event Handler plugin and configuring the Universal Forwarder:

Define RBAC resources

The teleport-event-handler configure command generated a file called teleport-event-handler-role.yaml. This file defines a teleport-event-handler role and a user with read-only access to the event API:

kind: role
metadata:
  name: teleport-event-handler
spec:
  allow:
    rules:
      - resources: ['event', 'session']
        verbs: ['list','read']
version: v5
---
kind: user
metadata:
  name: teleport-event-handler
spec:
  roles: ['teleport-event-handler']
version: v2

Move this file to your workstation (or recreate it by pasting the snippet above) and use tctl on your workstation to create the role and the user:

tctl create -f teleport-event-handler-role.yaml
user "teleport-event-handler" has been created
role 'teleport-event-handler' has been created

Enable impersonation of the Teleport Event Handler plugin user

In order for the Teleport Event Handler plugin to forward events from your Teleport cluster, it needs signed credentials from the cluster's certificate authority.

The teleport-event-handler user cannot request this itself, and requires another user to impersonate this account in order to request credentials. We will show you how to enable impersonation for your Teleport user so you can retrieve credentials for the Teleport Event Handler.

Create a role that enables your user to impersonate the teleport-event-handler user. First, paste the following YAML document into a file called teleport-event-handler-impersonator.yaml:

kind: role
version: v5
metadata:
  name: teleport-event-handler-impersonator
spec:
  options:
    # max_session_ttl defines the TTL (time to live) of SSH certificates
    # issued to the users with this role.
    max_session_ttl: 10h

  # This section declares a list of resource/verb combinations that are
  # allowed for the users of this role. By default nothing is allowed.
  allow:
    impersonate:
      users: ["teleport-event-handler"]
      roles: ["teleport-event-handler"]

Next, create the role:

tctl create -f teleport-event-handler-impersonator.yaml

Assign this role to your Teleport user by running the following commands, depending on whether you authenticate as a local Teleport user or via the github, saml, or oidc authentication connectors:

tctl get users/$(tsh status -f json | jq -r '.active.username') > myuser.yaml

tctl create -f myuser.yaml

tctl get github/github > github.yaml

  teams_to_roles:
    - organization: octocats 
      team: admins 
      roles:
        - access
+       - teleport-event-handler-impersonator

tctl create -f github.yaml

tctl get saml/mysaml > saml.yaml

  attributes_to_roles:
    - name: "groups" 
      value: "my-group" 
      roles:
        - access
+       - teleport-event-handler-impersonator

tctl create -f saml.yaml

tctl get oidc/myoidc > oidc.yaml

  claims_to_roles:
    - name: "groups" 
      value: "my-group" 
      roles:
        - access
+       - teleport-event-handler-impersonator

tctl create -f saml.yaml

Log out of your Teleport cluster and log in again to assume the new role.

Export the access plugin identity

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

The format of the credentials depends on whether you have set up your Teleport cluster so clients and services connect to the Teleport Proxy Service or to the Teleport Auth Service instead.

tctl auth sign --user=teleport-event-handler --out=auth.pem --ttl=240h

tctl auth sign --format=tls --user=teleport-event-handler --out=auth --ttl=240h

Move the credentials you generated to the host where you are running the Teleport Event Handler plugin.

Step 2/4. Configure the Universal Forwarder

In this step, you will configure the Universal Forwarder to receive audit logs from the Teleport Event Handler plugin and forward them to Splunk. The Event Handler sends audit logs as HTTP POST requests with the content type application/json.

We will assume that you assigned $SPLUNK_HOME to /opt/splunkforwarder when installing the Universal Forwarder.

sudo systemctl status SplunkForwarder.service
● SplunkForwarder.service - Systemd service file for Splunk, generated by 'splunk enable boot-start'
     Loaded: loaded (/lib/systemd/system/SplunkForwarder.service; enabled; vendor preset: enabled)
     Active: active (running) since Fri 2022-10-07 15:57:37 UTC; 2h 18min ago
   Main PID: 1772 (splunkd)
      Tasks: 53 (limit: 2309)
     Memory: 70.8M (limit: 1.8G)
     CGroup: /system.slice/SplunkForwarder.service
             ├─1772 splunkd --under-systemd --systemd-delegate=yes -p 8089 _internal_launch_under_systemd
             └─1810 [splunkd pid=1772] splunkd --under-systemd --systemd-delegate=yes -p 8089 _internal_launch_under_systemd [process-runner]

ExecStart=/opt/splunkforwarder/bin/splunk _internal_launch_under_systemd

Create an index for your audit logs

Create an index for your Teleport audit logs by visiting the home page of the Splunk UI and navigating to Settings > Indexes. Click New Index. Name your index teleport-audit-logs and assign the Index Data Type field to "Events".

The values of the remaining fields, Max raw data size and Searchable retention (days) depend on your organization's resources and practices for log management.

Click Save

Create a token for the Universal Forwarder

The Universal Forwarder authenticates client traffic using a token. To generate a token, visit the home page of the Splunk UI. Navigate to Settings > Data inputs In the Local inputs table, find the HTTP Event Collector row and click Add new

Enter a name you can use to recognize the token later so you can manage it, e.g., Teleport Audit Events. Click Next.

In the Input Settings view (above), next to the Source type field, click Select. In the Select Source Type dropdown menu, click Structured, then _json. Splunk will index incoming logs as JSON, which is the format the Event Handler uses to send logs to the Universal Forwarder.

In the Index section, select the teleport-audit-logs index you created earlier. Click Review then view the summary and click Submit. Copy the Token Value field and keep it somewhere safe so you can use it later in this guide.

Prepare a certificate file for the Universal Forwarder

The Universal Forwarder signs TLS certificates using a file that contains both an X.509-format certificate and an RSA private key. To prepare this, run the following commands on the Universal Forwarder host, where server.crt and server.key are two of the files you generated earlier with the teleport-event-handler configure the command:

cp server.crt server.pem
cat server.key >> server.pem

Allow the Universal Forwarder to access the certificate file:

sudo chown splunk:splunk server.pem

Configure the HTTP Event Collector

On your Universal Forwarder host, create a file at /opt/splunkforwarder/etc/system/local/inputs.conf with the following content:

[http]
port = 9061
disabled = false
serverCert = server.pem
sslPassword = 
requireClientCert = true

[http://audit]
token = 
index = teleport-audit-logs
allowQueryStringAuth = true

This configuration enables the HTTP input, which will listen on port 9061 and receive logs from the Teleport Event Handler Plugin, assigning them to the teleport-audit-logs index.

Assign serverCert to the path to the server.pem file you generated earlier.

To assign sslPassword, run the following command in the directory that contains fluent.conf:

cat fluent.conf | grep passphrase
private_key_passphrase "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"

Copy the passphrase and paste it as the value of sslPassword.

The token field in the [http://audit] section enables the Universal Forwarder to collect logs from HTTP clients that present a token. Assign token to the token you generated earlier.

allowQueryStringAuth enables the Teleport Event Handler to include the token in a query string, rather than the Authorization HTTP header (the default). This is necessary because the Teleport Event Handler does not currently support custom HTTP headers.

Configure TLS

To configure secure communications between the Universal Forwarder and the Teleport Event Handler, create a file called /opt/splunkforwarder/etc/system/local/server.conf with the following content (if this file already exists, add the following field in the [sslConfig] section):

[sslConfig]
sslRootCAPath =

Assign sslRootCAPath to the path of the ca.crt file you generated earlier.

Ensure that the Universal Forwarder can read the CA certificate:

sudo chmod +r ca.crt

Configure an output

Instruct the Universal Forwarder to send the logs it collects to Splunk.

Create a file at the path /opt/splunkforwarder/etc/system/local/outputs.conf with the following content:

[tcpout]
sslVerifyServerCert = true

[httpout]
httpEventCollectorToken =
uri =

Fill in httpEventCollectorToken with the token you generated earlier.

Assign uri to the following, replacing MYHOST with the hostname of your Splunk instance and 8088 with the port you are using for your Splunk HTTP Event Collector.

https://MYHOST:8088

The format of the URL to use will depend on your Splunk deployment. See the list of acceptable URL formats in the Splunk documentation.

Note that you must only include the scheme, host, and port of the URL. The Universal Forwarder will append the correct URL path of the Splunk ingestion API when forwarding logs.

Finally, restart the Universal Forwarder:

sudo systemctl restart SplunkForwarder

Step 3/4. Run the Teleport Event Handler plugin

Now that you have configured your Universal Forwarder to receive logs via HTTP and forward them to Splunk, you will ensure that the Teleport Event Handler plugin is configured to authenticate to the Universal Forwarder and your Teleport cluster, then run the Teleport Event Handler.

Complete the Teleport Event Handler configuration

Earlier, we generated a file called teleport-event-handler.toml to configure the Teleport Event Handler plugin. This file includes settings similar to the following:

storage = "./storage"
timeout = "10s"
batch = 20
namespace = "default"

[forward.fluentd]
ca = "/home/ca.crt"
cert = "/home/client.crt"
key = "/home/client.key"
url = "https://localhost:9061/test.log"

[teleport]
addr = "example.teleport.com:443"
identity = "identity"

Update the configuration file as follows.

Change forward.fluentd.url to the following:

url = "https://localhost:9061/services/collector/raw?token=MYTOKEN"

Ensure the URL includes the scheme, host and port of your Universal Forwarder's HTTP input, plus the URL path that the Universal Forwarder uses for raw data (/services/collector/raw).

Replace MYTOKEN with the token you generated earlier for the Splunk Universal Forwarder. If you are running the Universal Forwarder and Event Handler on separate hosts, replace localhost with your Universal Forwarder's IP address or domain name.

Change forward.fluentd.session-url to the same value as forward.fluentd.url, but with the query parameter key &noop= appended to the end:

session-url = "https://localhost:9061/services/collector/raw?token=MYTOKEN&noop="

For audit logs related to Teleport sessions, the Teleport Event Handler appends routing information to the URL that our HTTP input configuration does not use. Adding the noop query parameter causes the Teleport Event Handler to append the routing information as the parameter's value so the Universal Forwarder can discard it.

Change teleport.addr to the host and port of your Teleport Proxy Service, or the Auth Service if you have configured the Teleport Event Handler to connect to it directly, e.g., mytenant.teleport.sh:443.

chmod +r auth.pem

chmod +r auth.cas auth.crt auth.key

Start the Teleport Event Handler

Start the Teleport Teleport Event Handler as a daemon. To do so, create a systemd service definition at the path /usr/lib/systemd/system/teleport-event-handler.service with the following content:

[Unit]
Description=Teleport Event Handler
After=network.target

[Service]
Type=simple
Restart=on-failure
ExecStart=/usr/local/bin/teleport-event-handler start --config=/etc/teleport-event-handler.toml
ExecReload=/bin/kill -HUP $MAINPID
PIDFile=/run/teleport-event-handler.pid

[Install]
WantedBy=multi-user.target

Enable and start the plugin:

sudo systemctl enable teleport-event-handler
sudo systemctl start teleport-event-handler

teleport-event-handler start --config teleport-event-handler.toml --start-time "2021-05-05T00:00:00Z"

Once the Teleport Event Handler starts, you will see notifications about scanned and forwarded events:

sudo journalctl -u teleport-event-handler
DEBU   Event sent id:f19cf375-4da6-4338-bfdc-e38334c60fd1 index:0 ts:2022-09-21
18:51:04.849 +0000 UTC type:cert.create event-handler/app.go:140
...

Step 4/4. Visualize your audit logs in Splunk

Since our setup forwards audit logs to Splunk in the structured JSON format, Splunk automatically indexes them, so fields will be available immediately for use in visualizations. You can use these fields to create dashboards that track the way users are interacting with your Teleport cluster.

For example, from the Splunk UI home page, navigate to Search & Reporting > Dashboards > Create New Dashboard. Enter "Teleport Audit Log Types" for the title of your dashboard and click Classic Dashboards. Click Create then, in the Edit Dashboard view, click Add Panel.

In the Add Panel sidebar, click New > Column Chart. For the Search String field, enter the following:

index="teleport-audit-logs" | timechart count by event

Once you click Add to Dashboard you will see a count of Teleport event types over time, which gives you a general sense of how users are interacting with Teleport:

Troubleshooting connection issues

If the Teleport Event Handler is displaying error logs while connecting to your Teleport Cluster, ensure that:

• The certificate the Teleport Event Handler is using to connect to your Teleport cluster is not past its expiration date. This is the value of the --ttl flag in the tctl auth sign command, which is 12 hours by default.
• Ensure that in your Teleport Event Handler configuration file (teleport-event-handler.toml), you have provided the correct host and port for the Teleport Proxy Service or Auth Service.

Next steps

Now that you are exporting your audit logs to Splunk, consult our audit log reference so you can plan visualizations and alerts.

In this guide, we made use of impersonation to supply credentials to the Teleport Event Handler to communicate with your Teleport cluster. To learn more about impersonation, read our guide.

While this guide uses the tctl auth sign command to issue credentials for the Teleport Event Handler, production clusters should use Machine ID for safer, more reliable renewals. Read our guide to getting started with Machine ID.