What a free checker actually does
Most free scanners run a handful of quick, harmless tests from the outside: is your SSL certificate valid, do you send a few recommended security headers, is your software version visibly out of date, is your site on a malware blacklist. They finish in seconds because they don't probe anything. They read what your site announces about itself and grade it. That's useful for catching an expired certificate. It is not a security assessment.
What it skips
- Open ports and services. A free checker looks at your website on port 443. An attacker looks at everything else: a database port left open, a remote desktop service, an old FTP server, a management interface. A full scan probes every port on every address you own.
- Known vulnerabilities in what's running. Free tools might notice you're on an old version. A real scanner tests for the specific weaknesses in that version, thousands of them, and tells you which ones apply to you.
- Weak encryption in practice. "Certificate valid" is not the same as "encryption strong." Old TLS versions and weak cipher suites pass a certificate check and fail a real scan.
- Web application flaws. SQL injection, cross-site scripting, broken authentication. These live in your forms, logins, and search boxes. A header check can't see them; a web application scan is built to find them.
- The things you forgot you had. A staging server, an old subdomain, a test environment still online. Free checkers scan the address you typed. A proper scan starts by finding every address that belongs to you.
- Anything on the inside. Free checkers only see the outside. Internal scanning and agent-based scanning look at the systems behind your firewall, where most damage actually happens.
What "bank-grade" means
When you accept card payments, the card brands require your internet-facing systems to be scanned every quarter by a PCI Approved Scanning Vendor, an ASV. There are only about 80 ASVs in the world, and each one's scanning engine is tested and re-approved by the PCI Security Standards Council every year. The scan has to find any vulnerability rated medium or higher, and one finding fails the whole scan. It is the strictest routine scanning standard in general use, because money is on the line.
That standard isn't only for merchants. The same engine that decides whether a bank's merchant passes can scan any website, server, or application. Clone Systems has been an ASV since 2007, runs more than 100 million vulnerability checks a day, and sells that scan online to anyone who wants to know what an attacker would find.
Side by side
| Free website checker | Clone Systems external scan | |
|---|---|---|
| Time to result | Seconds | Minutes to hours, depending on scope |
| What it looks at | The web page you typed in | Every port and service on every address you own |
| Certificate check | Yes | Yes, plus protocol and cipher strength |
| Known vulnerability testing | Version lookup at best | Thousands of specific checks, updated daily |
| Web application flaws | No | Yes, with authenticated web app scanning |
| Finds forgotten assets | No | Yes, discovery is part of the scan |
| Rescans after you fix things | Run it again yourself | Free, unlimited rescans |
| Explains what to fix | A grade | Findings with remediation steps, plus an optional AI assistant that explains each one in plain language |
| Accepted by banks and auditors | No | Yes, from a PCI Approved Scanning Vendor |
| Price | Free | From $595 a year for 10 IPs; PCI ASV scans from $185 |
When a free checker is enough
If you run a personal blog with no logins, no forms, and no payments, a free checker plus keeping your software updated is a reasonable place to stop.
When it isn't
If your site takes payments, has customer logins, stores anyone's data, or is something your business would suffer without, a free checker is a false sense of security. The next step doesn't need a security team or a sales call: external vulnerability scanning from Clone Systems starts at $595 a year for 10 IPs, you buy it online, and you can run the first scan today.
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Clone Systems is a PCI Security Standards Council Approved Scanning Vendor, listed since 2007.