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How to block Nmap Scripting Engine

Operated by Nmap. is a component of Nmap, a free and open source network discovery and security auditing tool. It scans networks and hosts to determine available serv… Security Scanner Scans websites for security vulnerabilities, threats, and configuration weaknesses

How it identifies itself

Mozilla/5.0 (compatible; Nmap Scripting Engine; https://nmap.org/book/nse.html)

robots.txt

What the agent asks to be told. It obeys this or it does not — nothing enforces it.

robots.txt
User-agent: Nmap
Disallow: /

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 ~* "(Nmap|Nmap Scripting Engine)") {
    return 403;
}

Apache

In .htaccess or the vhost.

Apache
BrowserMatchNoCase "Nmap" bad_bot
BrowserMatchNoCase "Nmap Scripting Engine" 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 "Nmap") or (http.user_agent contains "Nmap Scripting Engine")

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 (['Nmap', 'Nmap Scripting Engine'] as $needle) {
        if (stripos($agent, $needle) !== false) {
            status_header(403);
            exit('Blocked: Nmap Scripting Engine');
        }
    }
});

robots.txt is a request. The rules below it are the wall.

Nmap Scripting Engine publishes a token, so the directive above will work for as long as it keeps honouring it — and nothing except its own good manners makes it. 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.

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