Try Falcosidekick on Ubuntu

Learn how to use Falcosidekick on Ubuntu

0. Requirements

0.1 Environment

This scenario has been tested on an Ubuntu 20.04 Virtual Machine. To use the same specifications, you can use the following Vagrantfile:

Vagrant.configure("2") do |config|

  # Ubuntu 20.04 = "bento/ubuntu-20.04"
  config.vm.box_version = "202303.13.0"

  # Falcosidekick-UI Dashboard HTTP Access "forwarded_port", guest: 2802, host: 2802


Also, this scenario requires Falco installation as described in Try Falco on Ubuntu and a container runtime, so you might need to through the following steps.

0.2 Install a Container Runtime

For simplicity, this scenario uses local containers, so it requires a container runtime like Docker or Podman. Run the following command on Ubuntu to install Docker:

$ sudo apt install -y

0.3 Verify that Falco is running

The current environment should have Falco already running as described in Try Falco on Ubuntu.

The following command will verify Falco is installed and running:

$ sudo systemctl status falco

● falco-kmod.service - Falco: Container Native Runtime Security with kmod
   Loaded: loaded (/usr/lib/systemd/system/falco-kmod.service; enabled; vendor preset: disabled)
   Active: active (running) since Thu 2023-01-26 12:25:55 UTC; 50s ago
   ... output omitted

1. Installing Falcosidekick

These are the main steps to install Falcosidekick on Ubuntu. Follow them and you should be able to use Falcosidekick in a matter of minutes.

Assuming Falco is already installed, here are the main steps to use Falcosidekick-UI (the graphical dashboard of Falcosidekick):

  • Create an instance of Redis
  • Start a Falcosidekick container
  • Start a Falcosidekick-UI container
  • Redirect the alerts from Falco to Falcosidekick

1.1 Prepare an instance of Redis

Falcosidekick-UI uses Redis to store and search data. A Redis container is the easiest way to make Redis available.

$ sudo docker run --detach --rm --network=host \
--name redis

Unable to find image 'redis/redis-stack-server:latest' locally
latest: Pulling from redis/redis-stack-server
Status: Downloaded newer image for redis/redis-stack-server:latest

1.2 Start Falcosidekick

We are going to use the container image to run Falcosidekick in the background. To enable the WebUI, set the WEBUI_URL environment variable when starting the container:

$ sudo docker run --detach --rm --network=host \
--env WEBUI_URL=http://localhost:2802 \
--name falcosidekick falcosecurity/falcosidekick:2.27.0

Unable to find image 'falcosecurity/falcosidekick:2.27.0' locally
2.27.0: Pulling from falcosecurity/falcosidekick
Status: Downloaded newer image for falcosecurity/falcosidekick:2.27.0

Falcosidekick output should look like the following:

$ sudo docker logs falcosidekick

2023/01/26 12:26:38 [INFO]  : Falco Sidekick version: 2.27.0
2023/01/26 12:26:38 [INFO]  : Enabled Outputs : [WebUI]
2023/01/26 12:26:38 [INFO]  : Falco Sidekick is up and listening on :2801

The Falcosidekick and Falcosidekick-UI ports are different. Falco uses the :2801 to send the alerts and we'll use the :2802 to connect later via the web browser.

1.3 Start Falcosidekick UI

Let's start Falocsidekick-UI to interact through a much more comfortable interface. The following command will start a Docker container based on the Falcosidekick UI image.

$ sudo docker run --detach --rm --network=host \
--name falcosidekick-ui falcosecurity/falcosidekick-ui

Unable to find image 'falcosecurity/falcosidekick-ui:latest' locally
latest: Pulling from falcosecurity/falcosidekick-ui
Status: Downloaded newer image for falcosecurity/falcosidekick-ui:latest

Falcosidekick UI output should look like the following:

$ sudo docker logs falcosidekick-ui

2023/01/26 15:56:12 [WARN] : Index does not exist
2023/01/26 15:56:12 [WARN] : Create Index
2023/01/26 15:56:12 [INFO] : Falcosidekick UI is listening on
2023/01/26 15:56:12 [INFO] : log level is info

1.4 Verify all containers are running

It's always useful to double check that every required container is running. Verify it with the docker ps command.

$ sudo docker ps

CONTAINER ID   IMAGE                                COMMAND                CREATED              STATUS              PORTS     NAMES
6bf43d19fe7e   falcosecurity/falcosidekick-ui       "./falcosidekick-ui"   About a minute ago   Up About a minute             falcosidekick-ui
bcc7aa743beb   falcosecurity/falcosidekick:2.27.0   "./falcosidekick"      2 minutes ago        Up 2 minutes                  falcosidekick
0dacd307fd91   redis/redis-stack-server:latest      "/"       3 minutes ago        Up 3 minutes                  redis

1.5 Redirect Falco output

It's time to redirect Falco alerts to Falcosidekick. Use the text editor of your choice and update the /etc/falco/falco.yaml file to have following settings:

json_output: true
  enabled: true
  url: http://localhost:2801

Restart Falco to apply these changes:

$ sudo systemctl restart falco

At this moment, Falco should be sending every alert to Falcosidekick.

2. Trying Falcosidekick in action

2.1 Generate a suspicious event

Run the following command to simulate a suspicious event:

$ sudo cat /etc/shadow > /dev/null

2.2 Access the Falcosidekick UI Dashboard

Go to the following URL to access Falcosidekick UI Dashboard:


If you are using a VM, you might need to forward the port or access the VM IP Address directly. The provided Vagrantfile, for examples, includes already this configuration.

There must be already a few events. Click on them to see the events detail.

Scan results

2.3 Event Generator

It is better to explore the Falcosidekick UI with more events. Run the following command to use event-generator to generate a variety of suspect actions that are detected by Falco rulesets.

$ sudo docker run -it --rm falcosecurity/event-generator \
run syscall --loop

Unable to find image 'falcosecurity/event-generator:latest' locally
latest: Pulling from falcosecurity/event-generator
Status: Downloaded newer image for falcosecurity/event-generator:latest

... output omitted ...

At this point, you can explore Falcosidekick UI. Notice the different priorities and tags.

Congratulations, you finished this scenario!

You should be able to install Falcosidekcik in any Ubuntu cluster and watch for suspicious behavior.

Click on Try Falco and try out the next scenario.

Last modified Mar 21, 2023: feat: add content for try-falco (e5d3e59)