CrowdSec

CrowdSec#

CrowdSec is a malicious activity detection tool. It looks for known patterns, like malicious login attempts, inside the applications logs and blocks the attacker IP address.

You can install only one CrowdSec instance for each node.

Configuration#

Once installed, CrowdSec is already fully functional and protect many NS8 applications.

From the web interface you can configure:

  • mail notification by adding one address per line inside Email notifications field: notifications will work only if Email notifications has been configured

  • IP and network which will never be blocked

  • dynamic and static ban time

As default, CrowdSec will send some telemetry to remote CrowdSec-owned servers. The servers use such data to compose a community blocklist which is sent back to your installation. If you do not want to share such data and disable the community blocklist, you can do it by disabling the Enable central API option under the Advanced section.

You can also connect your instance to CrowdSec console by filling the Enroll key optional field.

CrowdSec sends a daily notification email listing newly blocked IPs to the configured recipients. If the default threshold of 100 new blocked IPs is reached before the daily report, the notification is sent immediately. The Notification threshold field, under the Advanced section, controls this value and can be set between 1 and 10000.

Community blocklist vs Community blocklist (Lite)#

CrowdSec provides a community blocklist that is shared among all users. To activate this feature, you need to:

  • Enable the Central API option.

  • Enroll your CrowdSec instance in the console.

To access the full community blocklist (beyond the Lite version), you must share at least some ban decisions with the Central API every 24 hours. If your server has few or no bans, it will be considered as a blocking state, preventing access to the complete blocklist.

Command-line interface#

The cscli command is a powerful command-line interface to access advanced Crowdsec functions. To run cscli, you have to enter the application environment first. Type in a root shell the following command

runagent -m crowdsec1 bash

Then the cscli command becomes available. For instance, print the help message with

cscli --help
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