How to block Arachnid Shield API
Operated by Canadian Centre for Child Protection. Fetches a media file upon request of the domain owner and scans it for CSAM.
nginx
In the server block, then reload.
nginx
# In the server block. 403 rather than 444: a closed connection tells the
# operator nothing, and an agent that gets a status code can log it.
if ($http_user_agent ~* "(Arachnid Shield)") {
return 403;
}
Apache
In .htaccess or the vhost.
Apache
BrowserMatchNoCase "Arachnid Shield" bad_bot
<RequireAll>
Require all granted
Require not env bad_bot
</RequireAll>
Cloudflare
Security → WAF → Custom rules.
Cloudflare
# Security → WAF → Custom rules, action: Block (http.user_agent contains "Arachnid Shield")
WordPress
A child theme's functions.php, or a small plugin.
WordPress
// functions.php of a child theme, or a small plugin. Runs before WordPress
// builds the page, so a blocked agent costs one PHP process and no queries.
add_action('init', function () {
$agent = $_SERVER['HTTP_USER_AGENT'] ?? '';
foreach (['Arachnid Shield'] as $needle) {
if (stripos($agent, $needle) !== false) {
status_header(403);
exit('Blocked: Arachnid Shield API');
}
}
});
A rule on the user agent is a rule on a string it chose
The server rules match on a header the requester sets, which stops the agent that says who it is and not the one that copies somebody else's name. Botscope verifies identity against DNS and published address ranges, records which check decided each request, and shows you the ones that lied.