Opt-Out: Guide for Fediverse Administrators

Overview

The Cyber Circle Creator is a tool designed to leverage public APIs to gather information from Fediverse instances. This guide outlines how administrators of Fediverse instances can prevent the Cyber Circle Creator from accessing or fetching data from their instances.

The Functionality

One of the core functions within the Cyber Circle Creator is apiRequestWithHeaders. This asynchronous JavaScript function is responsible for making HTTP requests to the Fediverse instances, including a custom User-Agent header named cyber-circle-creator. It attempts to fetch data from specified URLs and handles errors with fallback mechanisms.

Relevant Code Snippet

async function apiRequestWithHeaders(url, options = null) {
    console.log(`Fetching :: ${url}`);

    const defaultUserAgent = { 'User-Agent': 'cyber-circle-creator' };
    
    // Merge headers
    options = options || {};
    options.headers = { ...(options.headers || {}), ...defaultUserAgent };

    if (options.body) {
        options.body = JSON.stringify(options.body);
    }

    try {
        const response = await fetch(url, options);
        
        if (response.ok) {
            return { response: { headers: response.headers, body: await response.json(), error: undefined }};
        }

        throw new Error(`Error fetching ${url}: ${response.status} ${response.statusText}`);
    } catch (error) {
        console.error(`Error fetching with User-Agent "cyber-circle":`, error);
        
        try {
            const fallbackResponse = await fetch(url, { ...(options ?? {}), headers: undefined });
            
            if (fallbackResponse.ok) {
                return { response: { headers: fallbackResponse.headers, body: await fallbackResponse.json(), error: undefined }};
            }
            
            throw new Error(`Error fetching ${url}: ${fallbackResponse.status} ${fallbackResponse.statusText}`);
        } catch (fallbackError) {
            console.error(`Fallback fetching without User-Agent failed:`, fallbackError);
            return {
                response: undefined,
                error: `Error fetching ${url}: ${fallbackError}`
            };
        }
    }
}

How to Block Cyber Circle Creator

Administrators who wish to restrict or prevent the Cyber Circle Creator tool from accessing their instance's data can follow these strategies:

User-Agent Blocking

Configure Web Server Rules: Most web servers allow configuration to block requests based on the User-Agent string. You can set up rules to block requests where User-Agent is cyber-circle-creator.
Web Application Firewalls (WAF): Utilize a WAF to detect and block requests containing this specific User-Agent.

Blocking User-Agent in Apache

To block a specific User-Agent, such as cyber-circle-creator, you can use the mod_rewrite module in the Apache configuration.

Enable the mod_rewrite module (if not already enabled):

sudo a2enmod rewrite

Add the following directives to your Apache configuration file (usually in /etc/apache2/sites-available/your-site.conf) or .htaccess file:

RewriteEngine On  
RewriteCond %{HTTP_USER_AGENT} cyber-circle-creator [NC]  
RewriteRule .* - [F,L]

This configuration checks for requests with the User-Agent cyber-circle-creator and returns a 403 Forbidden response.

Restart Apache to apply changes:

sudo systemctl restart apache2

Blocking User-Agent in Nginx

To block a User-Agent in Nginx, you can use the if directive within the server block of your Nginx configuration.

Edit the Nginx configuration file (usually located at /etc/nginx/sites-available/your-site or /etc/nginx/nginx.conf):

if ($http_user_agent ~* "cyber-circle-creator") {  
return 403;  
}

This will block any requests with the User-Agent cyber-circle-creator by returning a 403 Forbidden response.

Test the Nginx configuration for syntax errors:

sudo nginx -t

Reload Nginx to apply changes:

sudo systemctl reload nginx

Blocking User-Agent in HAProxy

For HAProxy, you can use ACLs to block requests based on the User-Agent string.

Edit the HAProxy configuration file (usually located at /etc/haproxy/haproxy.cfg):

frontend http_in  
bind *:80  
acl bad_user_agent hdr_sub(User-Agent) -i cyber-circle-creator  
http-request deny if bad_user_agent

This configuration will deny any HTTP requests with a User-Agent containing cyber-circle-creator.

Restart HAProxy to apply changes:

sudo systemctl restart haproxy

Public API Restrictions

The tool fetches data using public APIs defined in Fediverse node software. Some potential methods to restrict access include:

Rate Limiting: Implement rate limiting on the APIs to reduce the efficiency of the tool in gathering large amounts of data.
Access Control: Configure the instance to restrict API access to authenticated users or specific IP addresses.
API Configuration: Refer to the specific documentation for the Fediverse software running on your instance. There might be built-in options to customize which public data API endpoints are available or to add additional layers of authentication.

Important Note on Request Origin

The API requests made by the Cyber Circle Creator are not sent directly from a centralized server like ccc.cyber.to. Instead, they are initiated by the users who visit the webpage using the tool. This means that simply blocking the server will not prevent the requests, as they originate from the users' browsers. Therefore, focusing on tactics like User-Agent blocking and API configuration will be more effective.

Further Information

For detailed instructions about configuring these settings and further possibilities for securing your instance, consult the documentation related to your specific Fediverse software (e.g., Mastodon, Misskey, Pleroma). Administrator guides generally include essential best practices for enhancing privacy and security on an instance-wide level.