CSS Certificate Spider

scanner CSS Certificate Spider

CSS Security certificate validation spider

About this crawler

CSS Certificate Spider is a web crawler identified by the regular-expression pattern CSS Certificate Spider in the User-Agent request header. It is categorised as scanner. Use the regex above to detect, log, allow, or block CSS Certificate Spider traffic in your web server, CDN edge rules, or robots.txt.

Block-rate · top 25k sites

0.065%
latest snapshot
2026-06-04
matched key: Jigsaw CSS Validator
2026-05-012026-06-040.11%

Technical details

Name
CSS Certificate Spider
Pattern
CSS Certificate Spider
Tags
scanner
Reference
http://www.css-security.com/certificatespider/
Added
2026/05/09
Instances
1 known sample(s)

Sample User-Agent strings

CSS Certificate Spider (http://www.css-security.com/certificatespider/)

Block this crawler

robots.txt — disallow CSS Certificate Spider:

User-agent: CSS Certificate Spider Disallow: /

Apache .htaccess — return 403:

RewriteEngine On RewriteCond %{HTTP_USER_AGENT} CSS Certificate Spider [NC] RewriteRule .* - [F,L]

Nginx — return 403 inside a server block:

if ($http_user_agent ~* "CSS Certificate Spider") { return 403; }
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