nw-captcha

An example of PHP code for integrating Nemesida WAF with reCAPTCHA functionality (unblocking from IP addresses identified by Nemesida WAF as sources of DDoS, brute-force and flood attacks). nw-captcha along with configured Nginx is also available as a Docker-image.

Get reCAPTCHA keys

In the control panel Google reCAPTCHA get the site and secret keys for reCAPTCHA v2 and make changes in the file settings.php.

Initiate the SQLite file:

Create an SQLite file, initiate its structure. Navigate to the directory where the file will be stored (for example, /opt/nw-captcha/) and create it:

mkdir -p /opt/nw-captcha/
sqlite3 /opt/nw-captcha/nw.db

Create the required table:

  create table client
  (
      url         text,
      token       text,
      uuid        text,
      waf_id      text
  );

  create unique index client_uuid_uindex
      on client (uuid);

Description of parameters:

• url - URL of the server with the Nemesida WAF dynamic module installed (e.g. SCHEMA://HOST[:PORT]);
• token - the value of the nwaf_ban_captcha_token parameter;
• uuid is a unique instance ID Nemesida WAF;
• waf_id - the ID of the group license keys.

Add records to the database for each server with Nemesida WAF.

Example:

INSERT INTO client(url, token, uuid, waf_id) VALUES ("https://example.ru","token","uuid","waf_id");

The UUID and WAF ID are available in the Nginx service's error.log log.

Example:

# cat /var/log/nginx/error.log | grep 'WAF ID'

2022/01/01 00:00:00 [info] ...: Nemesida WAF: UUID: XXX; WAF ID: XXX. ...

Update the DB_PATH parameter in settings.php.

Activation

On a server with Nemesida WAF installed, in the settings nwaf.conf, set the parameter nwaf_ban_captcha_token, which defines the secret string for unlocking the IP address.

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Docker image

Docker container deploying

To deploy a container with nw-captcha, follow these steps:

1. Upload an image containing nw-captcha along with the configured Nginx:
   

# docker pull nemesida/nw-captcha

2. Create a directory:

# mkdir -p /opt/nwaf/nw-captcha

3. In the configuration files directory, create a file first-launch:

# touch /opt/nwaf/nw-captcha/first-launch

4. Launch the container with nw-captcha using the commands:

# iptables -t filter -N DOCKER
# docker run --rm -d -v /opt/nwaf/nw-captcha:/nw-captcha -p 80:80 nemesida/nw-captcha

where:

• --rm - deleting the container after completion of work;
• -d - running the container in the background;
• /opt/nwaf/nw-captcha:/nw-captcha - mounting a directory with configuration files inside the container;
• -p 80:80 - port forwarding 80 of the container to the external port 80.

To view the container ID (the CONTAINER ID column), you can use the command:

# docker ps -a

You can stop the container with the command:

# docker stop /container ID/

5. Allow read access for everyone for the nw-captcha directory:

# chmod -R 0555 /opt/nwaf/nw-captcha

6. Install SQLite3 and make configuration changes.

7. To launch the container, run the following commands:

# iptables -t filter -N DOCKER
# docker run --rm -d -v /opt/nwaf/nw-captcha:/nw-captcha -p 80:80 nemesida/nw-captcha

where:

• --rm - deleting the container after completion of work;
• -d - running the container in the background;
• /opt/nwaf/nw-captcha:/nw-captcha - mounting a directory with configuration files inside the container;
• -p 80:80 - port forwarding 80 of the container to the external port 80.

Docker image updating

1. Before updating the image nw-captcha, check whether the container is running. To do this, you need to view the container ID (the CONTAINER ID column) using the command:
   

# docker ps -a

2. If the container is running, stop it using the command:

# docker stop /container ID/

3. When the container is stopped, delete the image:

# rm docker image nemesida/nw-captcha

4. Upload an image containing nw-captcha:

# docker pull nemesida/nw-captcha

5. Launch the container with the image nw-captcha using the command:

# iptables -t filter -N DOCKER
# docker run --rm -d -v /opt/nwaf/nw-captcha/:/nw-captcha nemesida/nw-captcha