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Ingress Nginx

CrowdSec

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A lua plugin bouncer for Ingress Nginx Controller.

How does it work ?​

This bouncer leverages OpenResty lua's API, used the ingress nginx controller as a plugin.

Supported features:

  • Live mode (query the local API for each request)
  • Stream mode (pull the local API for new/old decisions every X seconds)
  • Ban remediation (can ban an IP address by redirecting him or returning a custom HTML page)
  • CAPTCHA remediation (can return a captcha)
  • Works with IPv4/IPv6
  • Support IP ranges (can apply a remediation on an IP range)

At the back, this bouncer uses crowdsec lua lib.

Installation​

Before installation

The Ingress nginx controller should be installed using the official helm chart

Using Helm​

First you need to create new ingress-nginx chart values file (crowdsec-ingress-bouncer.yaml) to upgrade the ingress controller with the crowdsec plugin.

controller:
  extraVolumes:
  - name: crowdsec-bouncer-plugin
    emptyDir: {}
  extraInitContainers:
  - name: init-clone-crowdsec-bouncer
    image: crowdsecurity/lua-bouncer-plugin
    imagePullPolicy: IfNotPresent
    env:
      - name: API_URL
        value: "http://crowdsec-service.crowdsec.svc.cluster.local:8080" # crowdsec lapi service-name
      - name: API_KEY
        value: "<API KEY>" # generated with `cscli bouncers add -n <bouncer_name>
      - name: BOUNCER_CONFIG
        value: "/crowdsec/crowdsec-bouncer.conf"
      - name: CAPTCHA_PROVIDER
        value: "recaptcha" # valid providers are recaptcha, hcaptcha, turnstile
      - name: SECRET_KEY
        value: "<your-captcha-secret-key>" # If you want captcha support otherwise remove this ENV VAR
      - name: SITE_KEY
        value: "<your-captcha-site-key>" # If you want captcha support otherwise remove this ENV VAR
      - name: BAN_TEMPLATE_PATH
        value: /etc/nginx/lua/plugins/crowdsec/templates/ban.html
      - name: CAPTCHA_TEMPLATE_PATH
        value: /etc/nginx/lua/plugins/crowdsec/templates/captcha.html
    command: ['sh', '-c', "sh /docker_start.sh; mkdir -p /lua_plugins/crowdsec/; cp -R /crowdsec/* /lua_plugins/crowdsec/"]
    volumeMounts:
    - name: crowdsec-bouncer-plugin
      mountPath: /lua_plugins
  extraVolumeMounts:
  - name: crowdsec-bouncer-plugin
    mountPath: /etc/nginx/lua/plugins/crowdsec
    subPath: crowdsec
  config:
    plugins: "crowdsec"
    lua-shared-dicts: "crowdsec_cache: 50m"
    server-snippet : |
      lua_ssl_trusted_certificate "/etc/ssl/certs/ca-certificates.crt"; # If you want captcha support otherwise remove this line
      resolver local=on ipv6=off;

This values upgrade your ingress deployment to add crowdsec lua lib as a plugin and run with the ingress controller. It used this docker image to copy the crowdsec lua library.

Once you have this patch we can upgrade the ingress-nginx chart.

helm -n ingress-nginx upgrade -f ingress-nginx-values.yaml -f crowdsec-ingress-bouncer.yaml ingress-nginx ingress-nginx

And then check if the ingress controller is running well.

kubectl -n ingress-nginx get pods
info

In stream mode, the bouncer will launch an internal timer to pull the local API at the first request made to the ingress controller.

Ingress controller Configuration​

The bouncer uses lua_shared_dict to share cache between all workers.

If you want to increase the cache size you need to change this value :

controller:
  config:
    lua-shared-dicts: "crowdsec_cache: 50m"

⚠️ Do not rename the crowdsec_cache shared dict, else the bouncer will not work anymore.

When using captcha remediation​

To make HTTP request in the bouncer, we need to set a resolver in the configuration. We choose local=on directive since we query google.com for the captcha verification, but you can replace it with a valid one.

To make secure HTTP request in the bouncer, we need to specify a trusted certificate (lua_ssl_trusted_certificate). You can also change this with a valid one :

  - /etc/ssl/certs/ca-certificates.crt (Debian/Ubuntu/Gentoo)
  - /etc/pki/tls/certs/ca-bundle.crt (Fedora/RHEL 6)
  - /etc/ssl/ca-bundle.pem (OpenSUSE)
  - /etc/pki/tls/cacert.pem (OpenELEC)
  - /etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem (CentOS/RHEL 7)
  - /etc/ssl/cert.pem (OpenBSD, Alpine)

References​

API_KEY​

API_KEY=<API_KEY>

CrowdSec Local API key.

Generated with sudo cscli bouncers add command.

API_URL​

API_URL=http://<ip>:<port>

CrowdSec local API URL.

BOUNCING_ON_TYPE​

BOUNCING_ON_TYPE=all|ban|captcha

Type of remediation we want to bounce. If you choose ban only and receive a decision with captcha as remediation, the bouncer will skip the decision.

FALLBACK_REMEDIATION​

FALLBACK_REMEDIATION=ban

The fallback remediation is applied if the bouncer receives a decision with an unknown remediation.

MODE​

MODE=stream|live

The bouncer mode:

  • stream: The bouncer will pull new/old decisions from the local API every X seconds (UPDATE_FREQUENCY parameter).

Note: The timer that pull the local API will be triggered after the first request.

  • live: The bouncer will query the local API for each requests (if IP is not in cache) and will store the IP in cache for X seconds (CACHE_EXPIRATION parameter).

REQUEST_TIMEOUT​

REQUEST_TIMEOUT=1000

Timeout in milliseconds for the HTTP requests done by the bouncer to query CrowdSec local API or captcha provider (for the captcha verification).

EXCLUDE_LOCATION​

EXCLUDE_LOCATION=/<path1>,/<path2>

The locations to exclude while bouncing. It is a list of location, separated by commas.

⚠️ It is not recommended to put EXCLUDE_LOCATION=/.

CACHE_EXPIRATION​

This option is only for the live mode.

CACHE_EXPIRATION=1

The cache expiration, in second, for IPs that the bouncer store in cache in live mode.

UPDATE_FREQUENCY​

This option is only for the stream mode.

UPDATE_FREQUENCY=10

The frequency of update, in second, to pull new/old IPs from the CrowdSec local API.

REDIRECT_LOCATION​

This option is only for the ban remediation.

REDIRECT_LOCATION=/<path>

The location to redirect the user when there is a ban.

If it is not set, the bouncer will return the page defined in the BAN_TEMPLATE_PATH with the RET_CODE (403 by default).

BAN_TEMPLATE_PATH​

This option is only for the ban remediation.

BAN_TEMPLATE_PATH=<path_to_html_template>

The path to a HTML page to return to IPs that trigger ban remediation.

By default, the HTML template is located in /etc/nginx/lua/plugins/crowdsec/templates/ban.html.

RET_CODE​

This option is only for the ban remediation.

RET_CODE=403

The HTTP code to return for IPs that trigger a ban remediation. If nothing specified, it will return a 403.

CAPTCHA_PROVIDER​

This option is only for the captcha remediation.

CAPTCHA_PROVIDER=<recaptcha | hcaptcha | turnstile>

SECRET_KEY​

This option is only for the captcha remediation.

SECRET_KEY=<captcha_secret_key>

The captcha secret key.

SITE_KEY​

This option is only for the captcha remediation.

SITE_KEY=<captcha_site_key>

The captcha site key.

CAPTCHA_TEMPLATE_PATH​

This option is only for the captcha remediation.

CAPTCHA_TEMPLATE_PATH=<path_to_html_template>

The path to a captcha HTML template.

The bouncer will try to replace {{captcha_site_key}} in the template with SITE_KEY parameter.

By default, the HTML template is located in /etc/nginx/lua/plugins/crowdsec/templates/captcha.html.

CAPTCHA_EXPIRATION​

This option is only for the captcha remediation.

CAPTCHA_EXPIRATION=3600

The time for which the captcha will be validated. After this duration, if the decision is still present in CrowdSec local API, the IPs address will get a captcha again.

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