crowdsec/docker

Quick reference

• Documentation and help: https://docs.crowdsec.net/
• Crowdsec concepts: https://docs.crowdsec.net/docs/concepts
• Where to file issues: https://github.com/crowdsecurity/crowdsec

What is Crowdsec

Crowdsec - An open-source, lightweight agent to detect and respond to bad behaviors. It also automatically benefits from our global community-wide IP reputation database.

How to use this image

Image flavors

All the following images are available on Docker Hub for the architectures 386, amd64, arm/v6, arm/v7, arm64.

Alpine

• crowdsecurity/crowdsec:{version}

Latest stable release recommended for production usage. Also available on GitHub (ghcr.io).

• crowdsecurity/crowdsec:dev

For development and testing, from the master branch.

since v1.4.2:

• crowdsecurity/crowdsec:slim

Reduced size by 60%, it does not include the notifier plugins nor the GeoIP database. If you need these details on decisions, run cscli hub upgrade inside the container to download the GeoIP database at runtime.

Debian (since v1.3.3)

• crowdsecurity/crowdsec:{version}-debian
• crowdsecurity/crowdsec:latest-debian

The debian version includes support for systemd and journalctl.

Custom

You can build your custom images with Dockerfile and Dockerfile-debian.

For example, if you need a Debian version without plugin notifiers:

$ docker build -f Dockerfile.debian --target slim .

The supported values for target are: full, geoip, plugins, slim.

Note: for crowdsec versions < 1.5.0, the syntax is

$ docker build -f Dockerfile.debian --build-arg=BUILD_ENV=slim .

Required configuration

Journalctl (only for debian image)

To use journalctl as a log stream, with or without the DSN environment variable, you need to mount the journal log from the host to the container itself. This can be done by adding the following volume mount to the docker command:

-v /var/log/journal:/run/log/journal

Logs ingestion and processing

Collections are a good place to start: https://docs.crowdsec.net/docs/collections/intro

Find collections, scenarios, parsers and postoverflows in the hub: https://hub.crowdsec.net

• Specify collections | scenarios | parsers | postoverflows to install via the environment variables (by default crowdsecurity/linux is installed)
• Mount volumes to specify which log files should be ingested by crowdsec

Acquisition (one file per datasource - recommended)

The files in /etc/crowdsec/acquis.d/ map the logs to the provided parsers. Find out more here: https://docs.crowdsec.net/docs/concepts/#acquisition

The directory might contain for example

ssh.yaml:

filenames:
 - /logs/auth.log
 - /logs/syslog
labels:
  type: syslog

apache.yaml:

filename: /logs/apache2/*.log
labels:
  type: apache2

labels.type: use syslog if the logs come from syslog, otherwise check the collection's documentation for the relevant type.

You can bind the directory from the host or have it in a Docker volume, the former is easier to update as you add more applications.

Note: In versions < 1.5, the acquisition directory is not configured by default. You can add it by mounting the /etc/crowdsec/config.yaml.local file:

crowdsec_service:
  acquisition_dir: /etc/crowdsec/acquis.d

Acquisition (single file - deprecated)

Before 1.5.0, it was recommended to put your acquisition configuration in /etc/crowdsec/acquis.yaml. You can still do it if you prefer but it's more effective to have one file per datasource.

filenames:
 - /logs/auth.log
 - /logs/syslog
labels:
  type: syslog
---
filename: /logs/apache2/*.log
labels:
  type: apache2

Recommended configuration

Volumes

We strongly suggest persisting the Crowdsec configuration and database in named volumes, or bind-mount them from the host, to avoid losing credentials and decision data in case of container destruction and recreation, version update, etc.

• Credentials and configuration: /etc/crowdsec
• Acquisition: /etc/crowdsec/acquis.d and/or /etc/crowdsec.acquis.yaml (yes, they can be nested in /etc/crowdsec)
• Database when using SQLite (default): /var/lib/crowdsec/data

Start a Crowdsec instance

docker run -d \
    -v crowdsec_config:/etc/crowdsec \
    -v local_path_to_crowdsec_config/acquis.d:/etc/crowdsec/acquis.d \
    -v local_path_to_crowdsec_config/acquis.yaml:/etc/crowdsec/acquis.yaml \
    -v crowdsec_data:/var/lib/crowdsec/data \
    -v /var/log/auth.log:/logs/auth.log:ro \
    -v /var/log/syslog.log:/logs/syslog.log:ro \
    -v /var/log/apache:/logs/apache:ro \
    -e COLLECTIONS="crowdsecurity/apache2 crowdsecurity/sshd" \
    -p 8080:8080 -p 6060:6060 \
    --name crowdsec crowdsecurity/crowdsec

... or docker-compose

Check this full-stack example using docker-compose: https://github.com/crowdsecurity/example-docker-compose

How to extend this image

Full configuration

The container is built with a specific docker configuration. If you need to change it and the docker variables (see below) are not enough, you can mount /etc/crowdsec/config.yaml.local from the host. The file should contain only the options from config.yaml that you want to change, as documented in Overriding values.

It is not recommended anymore to bind-mount the full config.yaml file and you should not need to do it.

Notifications

If you want to use the notification system, you have to use the full image (not slim) and mount at least a custom profiles.yaml and a notification configuration to /etc/crowdsec/notifications

docker run -d \
    -v ./profiles.yaml:/etc/crowdsec/profiles.yaml \
    -v ./http_notification.yaml:/etc/crowdsec/notifications/http_notification.yaml \
    -p 8080:8080 -p 6060:6060 \
    --name crowdsec crowdsecurity/crowdsec

Deployment use cases

Crowdsec is composed of an agent that parses logs and creates alerts, and a local API (LAPI) that transforms these alerts into decisions. Both functions are provided by the same executables, so the agent and the LAPI can run in the same or separate containers. In complex configurations, it makes sense to have agents on each machine that runs the protected applications, and a LAPI that gathers all signals from agents and communicates with the central API.

Register a new agent with LAPI

Without TLS authentication:

docker exec -it crowdsec_lapi_container_name cscli machines add agent_user_name --password agent_password

With TLS authentication:

Agents are automatically registered and don't need a username or password. The agents' names are derived from the IP address from which they connect.

Run an agent connected to LAPI

Add the following environment variables to the docker run command:

• DISABLE_LOCAL_API=true
• AGENT_USERNAME="agent_user_name" - agent_user_name previously registered with LAPI
• AGENT_PASSWORD="agent_password" - agent_password previously registered with LAPI
• LOCAL_API_URL="http://LAPI_host:LAPI_port"

Next steps

Bouncers

Crowdsec being a detection component, the remediation is implemented using bouncers. Each bouncer protects a specific component. Find out more:

https://hub.crowdsec.net/browse/#bouncers

https://docs.crowdsec.net/docs/user_guides/bouncers_configuration/

Automatic Bouncer Registration

Without TLS authentication:

You can register bouncers with the crowdsec container at startup, using environment variables or Docker secrets. You cannot use this process to update an existing bouncer without first deleting it.

To use environment variables, they should be in the format BOUNCER_KEY_<name>=<key>. e.g. BOUNCER_KEY_nginx=mysecretkey12345.

To use Docker secrets, the secret should be named bouncer_key_<name> with a content of <key>. e.g. bouncer_key_nginx with content mysecretkey12345.

A bouncer key can be any string but we recommend an alphanumeric value for consistency with the keys generated by crowdsec and to avoid problems with escaping special characters.

With TLS authentication:

Bouncers are automatically registered and don't need an API key. The bouncers' names are derived from the IP address from which they connect.

Console

We provide a web-based interface to get more from Crowdsec: https://docs.crowdsec.net/docs/console

Subscribe here: https://app.crowdsec.net

Caveats

Using binds rather than named volumes (complete explanation here) results in more complexity as you'll have to bind the relevant files one by one whereas with named volumes you can mount full configuration and data folders. On the other hand, named volumes are less straightforward to navigate.

Reference

Environment Variables

Note for persistent configurations (i.e. bind mount or volumes): when a variable is set, its value may be written to the appropriate file (usually config.yaml) each time the container is run.

Variable	Default	Description
CONFIG_FILE	/etc/crowdsec/config.yaml	Configuration file location
DISABLE_AGENT	false	Disable the agent, run a LAPI-only container
DISABLE_LOCAL_API	false	Disable LAPI, run an agent-only container
DISABLE_ONLINE_API	false	Disable online API registration for signal sharing
TEST_MODE	false	Don't run the service, only test the configuration: -e TEST_MODE=true
TZ		Set the timezone to ensure the logs have a local timestamp.
LOCAL_API_URL	http://0.0.0.0:8080	The LAPI URL, you need to change this when DISABLE_LOCAL_API is true: -e LOCAL_API_URL="http://lapi-address:8080"
PLUGIN_DIR	/usr/local/lib/crowdsec/plugins/	Directory for plugins: -e PLUGIN_DIR="<path>"
METRICS_PORT	6060	Port to expose Prometheus metrics
LAPI		(useless with DISABLE_LOCAL_API)
USE_WAL	false	Enable Write-Ahead Logging with SQLite
CUSTOM_HOSTNAME	localhost	Name for the local agent (running in the container with LAPI)
CAPI_WHITELISTS_PATH		Path for capi_whitelists.yaml
Agent		(these don't work with DISABLE_AGENT)
TYPE		Labels.type for file in time-machine: -e TYPE="<type>"
DSN		Process a single source in time-machine: -e DSN="file:///var/log/toto.log" or -e DSN="cloudwatch:///your/group/path:stream_name?profile=dev&backlog=16h" or -e DSN="journalctl://filters=_SYSTEMD_UNIT=ssh.service"
Bouncers
BOUNCER_KEY_<name>		Register a bouncer with the name <name> and a key equal to the value of the environment variable.
Console
ENROLL_KEY		Enroll key retrieved from the console to enroll the instance.
ENROLL_INSTANCE_NAME		To set an instance name and see it on the console
ENROLL_TAGS		Tags of the enrolled instance, for search and filter
Password Auth
AGENT_USERNAME		Agent username (to register if is LAPI or to use if it's an agent): -e AGENT_USERNAME="machine_id"
AGENT_PASSWORD		Agent password (to register if is LAPI or to use if it's an agent): -e AGENT_PASSWORD="machine_password"
TLS Encryption
USE_TLS	false	Enable TLS encryption (either as a LAPI or agent)
CACERT_FILE		CA certificate bundle (for self-signed certificates)
INSECURE_SKIP_VERIFY		Skip LAPI certificate validation
LAPI_CERT_FILE		LAPI TLS Certificate path
LAPI_KEY_FILE		LAPI TLS Key path
TLS Authentication		(these require USE_TLS=true)
CLIENT_CERT_FILE		Client TLS Certificate path (enable TLS authentication)
CLIENT_KEY_FILE		Client TLS Key path
AGENTS_ALLOWED_OU	agent-ou	OU values allowed for agents, separated by comma
BOUNCERS_ALLOWED_OU	bouncer-ou	OU values allowed for bouncers, separated by comma
Hub management
NO_HUB_UPGRADE	false	Skip hub update / upgrade when the container starts
COLLECTIONS		Collections to install, separated by space: -e COLLECTIONS="crowdsecurity/linux crowdsecurity/apache2"
PARSERS		Parsers to install, separated by space
SCENARIOS		Scenarios to install, separated by space
POSTOVERFLOWS		Postoverflows to install, separated by space
CONTEXTS		Context files to install, separated by space
APPSEC_CONFIGS		Appsec configs files to install, separated by space
APPSEC_RULES		Appsec rules files to install, separated by space
DISABLE_COLLECTIONS		Collections to remove, separated by space: -e DISABLE_COLLECTIONS="crowdsecurity/linux crowdsecurity/nginx"
DISABLE_PARSERS		Parsers to remove, separated by space
DISABLE_SCENARIOS		Scenarios to remove, separated by space
DISABLE_POSTOVERFLOWS		Postoverflows to remove, separated by space
DISABLE_CONTEXTS		Context files to remove, separated by space
DISABLE_APPSEC_CONFIGS		Appsec configs files to remove, separated by space
DISABLE_APPSEC_RULES		Appsec rules files to remove, separated by space
Log verbosity
LEVEL_INFO	false	Force INFO level for the container log
LEVEL_DEBUG	false	Force DEBUG level for the container log
LEVEL_TRACE	false	Force TRACE level (VERY verbose) for the container log
Developer options
CI_TESTING	false	Used during functional tests
DEBUG	false	Trace the entrypoint

File Locations

• /usr/local/bin/crowdsec - Crowdsec binary

• /usr/local/bin/cscli - Crowdsec CLI binary to interact with crowdsec

Find Us

• GitHub

Contributing

Please read contributing for details on our code of conduct, and the process for submitting pull requests to us.

License

This project is licensed under the MIT License - see the LICENSE file for details.