🧰 falcoctl

The official CLI tool for working with Falco and its ecosystem components.

Installation

Install falcoctl manually

You can download and install falcoctl manually following the appropriate instructions based on your operating system architecture.

Linux

AMD64

LATEST=$(curl -sI https://github.com/falcosecurity/falcoctl/releases/latest | awk '/location: /{gsub("\r","",$2);split($2,v,"/");print substr(v[8],2)}')
curl --fail -LS "https://github.com/falcosecurity/falcoctl/releases/download/v${LATEST}/falcoctl_${LATEST}_linux_amd64.tar.gz" | tar -xz
sudo install -o root -g root -m 0755 falcoctl /usr/local/bin/falcoctl

ARM64

LATEST=$(curl -sI https://github.com/falcosecurity/falcoctl/releases/latest | awk '/location: /{gsub("\r","",$2);split($2,v,"/");print substr(v[8],2)}')
curl --fail -LS "https://github.com/falcosecurity/falcoctl/releases/download/v${LATEST}/falcoctl_${LATEST}_linux_arm64.tar.gz" | tar -xz
sudo install -o root -g root -m 0755 falcoctl /usr/local/bin/falcoctl

NOTE: Make sure /usr/local/bin is in your PATH environment variable.

MacOS

The easiest way to install on MacOS is via Homebrew:

brew install falcoctl

Alternatively, you can download directly from the source:

Intel

LATEST=$(curl -sI https://github.com/falcosecurity/falcoctl/releases/latest | awk '/location: /{gsub("\r","",$2);split($2,v,"/");print substr(v[8],2)}')
curl --fail -LS "https://github.com/falcosecurity/falcoctl/releases/download/v${LATEST}/falcoctl_${LATEST}_darwin_amd64.tar.gz" | tar -xz
chmod +x falcoctl
sudo mv falcoctl /usr/local/bin/falcoctl

Apple Silicon

LATEST=$(curl -sI https://github.com/falcosecurity/falcoctl/releases/latest | awk '/location: /{gsub("\r","",$2);split($2,v,"/");print substr(v[8],2)}')
curl --fail -LS "https://github.com/falcosecurity/falcoctl/releases/download/v${LATEST}/falcoctl_${LATEST}_darwin_arm64.tar.gz" | tar -xz
chmod +x falcoctl
sudo mv falcoctl /usr/local/bin/falcoctl

Alternatively, you can manually download falcoctl from the falcoctl releases page on GitHub.

Install falcoctl from source

You can install falcoctl from source. First thing clone the falcoctl repository, build the falcoctl binary, and move it to a file location in your system PATH.

git clone https://github.com/falcosecurity/falcoctl.git
cd falcoctl
make falcoctl
sudo mv falcoctl /usr/local/bin/falcoctl

Getting Started

Installing an artifact

This tutorial aims at presenting how to install a Falco artifact. The next few steps will present us with the fundamental commands of falcoctl and how to use them.

First thing, we need to add a new index to falcoctl:

$ falcoctl index add falcosecurity https://falcosecurity.github.io/falcoctl/index.yaml

We just downloaded the metadata of the artifacts hosted and distributed by the falcosecurity organization and made them available to the falcoctl tool. Now let's check that the index file is in place by running:

$ falcoctl index list

We should get an output similar to this one:

NAME            URL                                                     ADDED                   UPDATED            
falcosecurity   https://falcosecurity.github.io/falcoctl/index.yaml     2022-10-25 15:01:25     2022-10-25 15:01:25

Now let's search all the artifacts related to cloudtrail:

$ falcoctl artifact search cloudtrail
INDEX           ARTIFACT                TYPE            REGISTRY        REPOSITORY                              
falcosecurity   cloudtrail              plugin          ghcr.io         falcosecurity/plugins/plugin/cloudtrail 
falcosecurity   cloudtrail-rules        rulesfile       ghcr.io         falcosecurity/plugins/ruleset/cloudtrail

Lets install the cloudtrail plugin:

$ falcoctl artifact install cloudtrail --plugins-dir=./
 INFO  Reading all configured index files from "/home/aldo/.config/falcoctl/indexes.yaml"
 INFO  Preparing to pull "ghcr.io/falcosecurity/plugins/plugin/cloudtrail:latest"
 INFO  Remote registry "ghcr.io" implements docker registry API V2
 INFO  Pulling 44136fa355b3: ############################################# 100% 
 INFO  Pulling 80e0c33f30c0: ############################################# 100% 
 INFO  Pulling b024dd7a2a63: ############################################# 100% 
 INFO  Artifact successfully installed in "./" 

Install the cloudtrail-rules rulesfile:

$ ./falcoctl artifact install cloudtrail-rules --rulesfiles-dir=./
 INFO  Reading all configured index files from "/home/aldo/.config/falcoctl/indexes.yaml"
 INFO  Preparing to pull "ghcr.io/falcosecurity/plugins/ruleset/cloudtrail:latest"
 INFO  Remote registry "ghcr.io" implements docker registry API V2
 INFO  Pulling 44136fa355b3: ############################################# 100% 
 INFO  Pulling e0dccb7b0f1d: ############################################# 100% 
 INFO  Pulling 575bced78731: ############################################# 100% 
 INFO  Artifact successfully installed in "./"

We should have now two new files in the current directory: aws_cloudtrail_rules.yaml and libcloudtrail.so.

Falcoctl Configuration Files

/etc/falcoctl/falcoctl.yaml

The falco configuration file is a yaml file that contains some metadata about the falcoctl behaviour. It contains the list of the indexes where the artifacts are listed, how often and which artifacts needed to be updated periodically. The default configuration is stored in /etc/falcoctl/falcoctl.yaml. This is an example of a falcoctl configuration file:

artifact:
  follow:
    every: 6h0m0s
    falcoVersions: http://localhost:8765/versions
    refs:
    - falco-rules:0
    - my-rules:1
  install:
    refs:
      - cloudtrail-rules:latest
      - cloudtrail:latest
    rulesfilesdir: /tmp/rules
    pluginsdir: /tmp/plugins
indexes:
- name: falcosecurity
  url: https://falcosecurity.github.io/falcoctl/index.yaml
- name: my-index
  url: https://example.com/falcoctl/index.yaml
registry:
  auth:
    basic:
    - password: password
      registry: myregistry.example.com:5000
      user: user
    oauth:
    - registry: myregistry.example.com:5001
      clientsecret: "999999"
      clientid: "000000"
      tokenurl: http://myregistry.example.com:9096/token
    gcp:
    - registry: europe-docker.pkg.dev

~/.config/falcoctl/

The ~/.config/falcoctl/ directory contains:

• cache objects
• OAuth2 client credentials

~/.config/falcoctl/indexes.yaml

This file is used for cache purposes and contains the index refs added by the command falcoctl index add [name] [ref]. The index ref is enriched with two timestamps to track when it was added and the last time is was updated. Once the index ref is added, falcoctl will download the real index in the ~/.config/falcoctl/indexes/ directory. Moreover, every time the index is fetched, the updated_timestamp is updated.

~/.config/falcoctl/clientcredentials.json

The command falcoctl registry auth oauth will add the clientcredentials.json file to the ~/.config/falcoctl/ directory. That file will contain all the needed information for the OAuth2 authetication.

Falcoctl Commands

Falcoctl index

The index file is a yaml file that contains some metadata about the Falco artifacts. Each entry carries information such as the name, type, registry, repository and other info for the given artifact. Different falcoctl commands rely on the metadata contained in the index file for their operation. This is an example of an index file:

- name: okta
  type: plugin
  registry: ghcr.io
  repository: falcosecurity/plugins/plugin/okta
  description: Okta Log Events
  home: https://github.com/falcosecurity/plugins/tree/master/plugins/okta
  keywords:
    - audit
    - log-events
    - okta
  license: Apache-2.0
  maintainers:
    - email: cncf-falco-dev@lists.cncf.io
      name: The Falco Authors
  sources:
    - https://github.com/falcosecurity/plugins/tree/master/plugins/okta
- name: okta-rules
  type: rulesfile
  registry: ghcr.io
  repository: falcosecurity/plugins/ruleset/okta
  description: Okta Log Events
  home: https://github.com/falcosecurity/plugins/tree/master/plugins/okta
  keywords:
    - audit
    - log-events
    - okta
    - okta-rules
  license: Apache-2.0
  maintainers:
    - email: cncf-falco-dev@lists.cncf.io
      name: The Falco Authors
  sources:
    - https://github.com/falcosecurity/plugins/tree/master/plugins/okta/rules

Index Storage Backends

Indices for falcoctl can be retrieved from various storage backends. The supported index storage backends are listed in the table below. Note if you do not specify a backend type when adding a new index falcoctl will try to guess based on the URI Scheme:

Name	URI Scheme	Description
http	http://	Can be used to retrieve indices via simple HTTP GET requests.
https	https://	Convenience alias for the HTTP backend.
gcs	gs://	For indices stored as Google Cloud Storage objects. Supports application default credentials.

falcoctl index add

New indexes are configured to be used by the falcoctl tool by adding them through the index add command. There are no limits to the number of indexes that can be added to the falcoctl tool. When adding a new index the tool adds a new entry in a file called indexes.yaml and downloads the index file in ~/.config/falcoctl. The same folder is used to store the indexes.yaml file, too. The following command adds a new index named falcosecurity:

$ falcoctl index add falcosecurity https://falcosecurity.github.io/falcoctl/index.yaml

The following command adds the same index falcosecurity, but explicitly sets the storage backend to https:

$ falcoctl index add falcosecurity https://falcosecurity.github.io/falcoctl/index.yaml https

falcoctl index list

Using the index list command you can check the configured indexes in your local system:

$ falcoctl index list
NAME            URL                                                     ADDED                   UPDATED            
$ falcosecurity   https://falcosecurity.github.io/falcoctl/index.yaml     2022-10-25 15:01:25     2022-10-25 15:01:25

falcoctl index update

The index update allows to update a previously configured index file by syncing the local one with the remote one:

$ falcoctl index update falcosecurity

falcoctl index remove

When we want to remove an index file that we configured previously, the index remove command is the one we need:

$ falcoctl index remove falcosecurity

The above command will remove the falcosecurity index from the local system.

Falcoctl artifact

The falcoctl tool provides different commands to interact with Falco artifacts. It makes easy to seach, install and get info for the artifacts provided by a given index file. For these commands to properly work we need to configure at least an index file in our system as shown in the previus section.

Falcoctl artifact search

The artifact search command allows to search for artifacts provided by the index files configured in falcoctl. The command supports searches by name or by keywords and displays all the artifacts that match the search. Assuming that we have already configured the index provided by the falcosecurity organization, the following command shows all the artifacts that work with Kubernetes:

$ falcoctl artifact search kubernetes
INDEX           ARTIFACT        TYPE            REGISTRY        REPOSITORY                            
falcosecurity   k8saudit        plugin          ghcr.io         falcosecurity/plugins/plugin/k8saudit 
falcosecurity   k8saudit-rules  rulesfile       ghcr.io         falcosecurity/plugins/ruleset/k8saudit

Falcoctl artifact info

As per the name, artifact info prints some info for a given artifact:

$ falcoctl artifact info k8saudit
REF                                             TAGS                                          
ghcr.io/falcosecurity/plugins/plugin/k8saudit   0.1.0 0.2.0 0.2.1 0.3.0 0.4.0-rc1 0.4.0 latest

It shows the OCI reference and tags for the artifact of interest. Thot info is usually used with other commands.

Falcoctl artifact install

The above commands help us to find all the necessary info for a given artifact. The artifact install command installs an artifact. It pulls the artifact from remote repository, and saves it in a given directory. The following command installs the k8saudit plugin in the default path:

$ falcoctl artifact install k8saudit
 INFO  Reading all configured index files from "/home/aldo/.config/falcoctl/indexes.yaml"
 INFO  Preparing to pull "ghcr.io/falcosecurity/plugins/plugin/k8saudit:latest"
 INFO  Remote registry "ghcr.io" implements docker registry API V2                                                                                                                                              
 INFO  Pulling 44136fa355b3: ############################################# 100% 
 INFO  Pulling ded0b5419f40: ############################################# 100% 
 INFO  Pulling 107d1230f3f0: ############################################# 100% 
 INFO  Artifact successfully installed in "/usr/share/falco/plugins"

By default, if we give the name of an artifact it will search for the artifact in the configured index files and downlaod the latest version. The commands accepts also the OCI reference of an artifact. In this case, it will ignore the local index files. The command has two flags:

• --plugins-dir: directory where to install plugins. Defaults to /usr/share/falco/plugins;
• --rulesfiles-dir: directory where to install rules. Defaults to /etc/falco.

If the repositories of the artifacts your are trying to install are not public then you need to authenticate to the remote registry.

Falcoctl artifact follow

The above commands allow us to keep up-to-date one or more given artifacts. The artifact follow command checks for updates on a periodic basis and then downloads and installs the latest version, as specified by the passed tags. It pulls the artifact from remote repository, and saves it in a given directory. The following command installs the github-rules rulesfile in the default path:

 $ falcoctl artifact follow github-rules
 WARN  falcosecurity already exists with the same configuration, skipping
 INFO  Reading all configured index files from "/root/.config/falcoctl/indexes.yaml"
INFO: Creating follower for "github-rules", with check every 6h0m0s
 INFO  Starting follower for "ghcr.io/falcosecurity/plugins/ruleset/github:latest"
 INFO   (ghcr.io/falcosecurity/plugins/ruleset/github:latest) found new version under tag "latest"
 INFO   (ghcr.io/falcosecurity/plugins/ruleset/github:latest) artifact with tag "latest" correctly installed

By default, if we give the name of an artifact it will search for the artifact in the configured index files and downlaod the latest version. The commands accepts also the OCI reference of an artifact. In this case, it will ignore the local index files. The command can specify the directory where to install the rulesfile artifacts through the --rulesfiles-dir flag (defaults to /etc/falco).

If the repositories of the artifacts your are trying to install are not public then you need to authenticate to the remote registry.

Please note that only rulesfile artifact can be followed.

Falcoctl registry

The registry commands interact with OCI registries allowing the user to authenticate, pull and push artifacts. We have tested the falcoctl tool with the ghcr.io registry, but it should work with all the registries that support the OCI artifacts.

Falcoctl registry auth

The registry auth command authenticates a user to a given OCI registry.

Falcoctl registry auth basic

The registry auth basic command authenticates a user to a given OCI registry using HTTP Basic Authentication. Run the command in advance for any private registries.

Falcoctl registry auth oauth

The registry auth oauth command retrieves access and refresh tokens for OAuth2.0 client credentials flow authentication. Run the command in advance for any private registries.

Falcoctl registry auth gcp

The registry auth gcp command retrieves access tokens using Application Default Credentials. In particular, it supports access token retrieval using Google Compute Engine metadata server and Workload Identity, useful to authenticate your deployed Falco workloads. Run the command in advance for Artifact Registry authentication.

Two typical use cases:

1. You are manipulating some rules or plugins and use falcoctl to pull or push to an Artifact Registry:
   1. run gcloud auth application-default login to generate a JSON credential file that will be used by applications.
   2. run falcoctl registry auth gcp europe-docker.pkg.dev for instance to use Application Default Credentials to connect to any repository hosted at europe-docker.pkg.dev.
2. You have a Falco instance with Falcoctl as a side car, running in a GKE cluster with Workload Identity enabled:
   1. Workload Identity is correctly set up for the Falco instance (see the documentation).
   2. Add an environment variable like FALCOCTL_REGISTRY_AUTH_GCP=europe-docker.pkg.dev to enable GCP authentication for the europe-docker.pkg.dev registry.
   3. The Falcoctl instance will get access tokens from the metadata server and use them to authenticate to the registry and download your rules.

Falcoctl registry push

It pushes local files and references the artifact uniquely. The following command shows how to push a local file to a remote registry:

$ falcoctl registry push --type=plugin ghcr.io/falcosecurity/plugins/plugin/cloudtrail:0.3.0 clouddrail-0.3.0-linux-x86_64.tar.gz --platform linux/amd64

The type denotes the artifact type in this case plugins. The ghcr.io/falcosecurity/plugins/plugin/cloudtrail:0.3.0 is the unique reference that points to the artifact. Currently, falcoctl supports only two types of artifacts: plugin and rulesfile. Based on artifact type the commands accepts different flags:

• --add-floating-tags: add the floating tags for the major and minor versions
• --annotation-source: set annotation source for the artifact;
• --depends-on: set an artifact dependency (can be specified multiple times). Example: --depends-on my-plugin:1.2.3
• --tag: additional artifact tag. Can be repeated multiple time
• --type: type of artifact to be pushed. Allowed values: rulesfile, plugin, asset

Falcoctl registry pull

Pulling artifacts involves specifying the reference. The type of artifact is not required since the tool will implicitly extract it from the OCI artifact:

$ falcoctl registry pull ghcr.io/falcosecurity/plugins/plugin/cloudtrail:0.3.0

Falcoctl Environment Variables

The arguments of falcoctl can passed as arguments through:

• command line options
• environment variables
• configuration file

The falcoctl arguments can be passed through these different modalities are prioritized in the following order: command line options, environment variables, and finally the configuration file. This means that if an argument is passed through multiple modalities, the value set in the command line options will take precedence over the value set in environment variables, which will in turn take precedence over the value set in the configuration file.

This is the list of the environment variable that falcoctl will use:

Name	Content
FALCOCTL_REGISTRY_AUTH_BASIC	registry,username,password;registry1,username1,password1
FALCOCTL_REGISTRY_AUTH_OAUTH	registry,client-id,client-secret,token-url;registry1
FALCOCTL_REGISTRY_AUTH_GCP	registry;registry1
FALCOCTL_INDEXES	index-name,https://falcosecurity.github.io/falcoctl/index.yaml
FALCOCTL_ARTIFACT_FOLLOW_EVERY	6h0m0s
FALCOCTL_ARTIFACT_FOLLOW_CRON	cron-formatted-string
FALCOCTL_ARTIFACT_FOLLOW_REFS	ref1;ref2
FALCOCTL_ARTIFACT_FOLLOW_FALCOVERSIONS	falco-version-url
FALCOCTL_ARTIFACT_FOLLOW_RULESFILEDIR	rules-directory-path
FALCOCTL_ARTIFACT_FOLLOW_PLUGINSDIR	plugins-directory-path
FALCOCTL_ARTIFACT_FOLLOW_TMPDIR	tmp-directory-path
FALCOCTL_ARTIFACT_INSTALL_REFS	ref1;ref2
FALCOCTL_ARTIFACT_INSTALL_RULESFILESDIR	rules-directory-path
FALCOCTL_ARTIFACT_INSTALL_PLUGINSDIR	plugins-directory-path
FALCOCTL_ARTIFACT_NOVERIFY

Please note that when passing multiple arguments via an environment variable, they must be separated by a semicolon. Moreover, multiple fields of the same argument must be separated by a comma.

Here is an example of falcoctl usage with environment variables:

$ export FALCOCTL_REGISTRY_AUTH_OAUTH="localhost:6000,000000,999999,http://localhost:9096/token"
$ falcoctl registry oauth 

Container image signature verification

Official container images for Falcoctl, starting from version 0.5.0, are signed with cosign v2. To verify the signature run:

$ FALCOCTL_VERSION=x.y.z # e.g. 0.5.0
$ cosign verify docker.io/falcosecurity/falcoctl:$FALCOCTL_VERSION --certificate-oidc-issuer=https://token.actions.githubusercontent.com --certificate-identity-regexp=https://github.com/falcosecurity/falcoctl/ --certificate-github-workflow-ref=refs/tags/v$FALCOCTL_VERSION