Free Website Vulnerability Scanner: Check Your Security Headers, SSL, and More

What Is a Website Vulnerability Scanner?

A website vulnerability scanner is a tool that inspects your public-facing web application for security misconfigurations, missing protections, and known weaknesses. Unlike a penetration test, it does not attempt to exploit anything: it reads your server's response headers, checks your SSL certificate, examines your cookie flags, and compares your setup against established security standards.

Most websites have at least one misconfiguration attackers can use. The Protego scanner surfaces them in seconds. Scan your website now for free

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What the Protego Scanner Checks

The scanner runs a comprehensive audit across seven security layers every time you hit Scan: Security Headers (9 checks) Missing headers are the most common finding on the web. The scanner checks for Content-Security-Policy, Strict-Transport-Security (HSTS), X-Frame-Options, X-Content-Type-Options, Referrer-Policy, Permissions-Policy, Cross-Origin-Opener-Policy, Cross-Origin-Resource-Policy, and more. SSL/TLS Certificate Validates the certificate is trusted, not expired, and running a modern protocol. Deprecated TLS 1.0 and 1.1 are flagged. HTTP to HTTPS Redirect Checks whether your site forces visitors off plain HTTP. If it does not, session cookies can be intercepted before HTTPS kicks in. Cookie Security Flags Every cookie your server sets is audited for the Secure, HttpOnly, and SameSite attributes. Missing flags are a common root cause for session hijacking and CSRF attacks. CORS Configuration An overly permissive Access-Control-Allow-Origin (especially * combined with Allow-Credentials: true) is a critical misconfiguration. The scanner detects it and explains the risk. WAF and CDN Detection Tells you whether a Web Application Firewall (Cloudflare, AWS, Fastly, Akamai) sits in front of your origin. If none is detected, you get a recommendation. DNS Email Security Checks SPF, DMARC, and CAA records so you know whether your domain can be spoofed in phishing emails.

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How It Works: 3 Steps

1. Enter your domain at protego.me/tools/vulnerability-scanner. Bare domains like example.com work fine: no need to type the full URL.
2. Click Scan Now. The tool connects to your server, fetches the HTTP response headers, validates the SSL certificate, probes for redirect behavior, and analyzes cookie and CORS settings. Standard scan takes around 10 seconds.
3. Read your security grade. Every finding is rated Critical, High, Medium, or Low. Each one includes a plain-English explanation and ready-to-paste fix code for Nginx, Apache, Next.js, and Cloudflare.

No account required. No rate limits for normal use. The tool is free and always will be.

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Deep Scan Mode: 16 Additional Checks

Enable Deep Scan to go further. It extends the standard audit with active probing:

• Sensitive path exposure: Attempts to access around 25 commonly exposed paths (admin panels, .env files, backup archives, debug endpoints).
• Vulnerable JavaScript libraries: Parses your page HTML, identifies frontend libraries and their versions, and matches them against known CVEs.
• TLS 1.0/1.1 probe: Actively tests whether your server accepts deprecated protocol versions even if the response says TLS 1.2.
• Supply chain audit: Identifies third-party scripts loaded by your page and flags untrusted or unexpected sources.
• Mixed content detection: Finds HTTP resources loaded on HTTPS pages that browsers will silently block for users.
• HTTP method audit: Tests for dangerous methods like PUT, DELETE, and TRACE that should be disabled on production servers.
• robots.txt analysis: Checks whether your robots.txt inadvertently reveals sensitive paths to crawlers.
• Credential and secret scan: Looks for patterns in HTTP responses that suggest exposed API keys or tokens.

Deep Scan takes around 50 seconds. The extra time is worth it before any major deployment or audit.

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Who Should Use This Tool

Developers and DevOps engineers who want a quick pre-deployment security check. Run it after every major configuration change to catch header regressions before they hit production. Security teams who need a lightweight, non-invasive way to get a baseline on external-facing assets without spinning up a full DAST platform. SaaS founders and product managers who want to know their site's security posture without relying entirely on a third party or waiting for a compliance audit. Compliance-conscious teams running PCI-DSS, SOC 2, or ISO 27001 programs where documented regular scans are a control requirement. The shareable report link makes it easy to attach evidence to tickets.

Anyone responsible for a public website can benefit from a 15-second scan. Most sites fail at least one check.

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Why Use the Protego Scanner

There are several security header scanners out there. Here is what makes this one worth bookmarking: Actionable fix code, not just grades. When a header is missing, you get ready-to-paste code for your specific platform: Nginx, Apache, Next.js, or Cloudflare. No googling required. Fix All with AI. Copy all actionable findings into a single AI prompt you can paste into Claude, ChatGPT, or Cursor to get a guided remediation plan for your specific stack. Shareable reports. After a scan, generate a shareable link that encodes the full report: no account, no login, just a URL you can drop into a Slack thread or a GitHub issue. SSL certificate monitoring. Enter your email after a scan and Protego will alert you 30, 14, and 7 days before your certificate expires: free, no subscription. Deep Scan for real attacker perspective. Most free scanners stop at headers. Deep Scan probes for the misconfigurations attackers actively look for: exposed admin paths, outdated JS libraries with CVEs, and supply chain risks.

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Frequently Asked Questions

Is the vulnerability scanner completely free?

Yes. Both Standard and Deep Scan modes are free with no account required. There are no hidden limits for normal use.

Does the scanner test for XSS or SQL injection?

No. The scanner is a configuration auditor, not an exploit tool. It checks for missing security controls (headers, SSL, cookie flags) that make attacks like XSS possible: but it does not inject payloads or test application logic. For application-layer testing, you need a dedicated DAST tool or a manual penetration test.

How accurate are the findings?

HTTP headers are deterministic: a missing header is a missing header. SSL certificate validity is verified against the CA chain. The scanner does not produce false positives on these checks. Deep Scan path probing relies on HTTP status codes and is less precise for unusual server configurations, but findings are always explained with enough context to verify manually.

Can I scan a competitor's website?

The scanner should only be used on websites you own or have explicit written permission to test. Unauthorized scanning may violate the Computer Fraud and Abuse Act, the UK Computer Misuse Act, and similar laws in other jurisdictions.

How often should I scan my site?

For production websites, scan at minimum after every significant deployment and once a month as a baseline check. If your site handles payment data or personal information, weekly scans are a reasonable baseline.

What does a Content-Security-Policy do?

A CSP header tells the browser which sources are allowed to load scripts, styles, images, and other resources. Without one, an attacker who finds an XSS vulnerability can inject arbitrary scripts. A well-configured CSP turns a critical vulnerability into a much harder-to-exploit one.

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Share Your Results and Let Us Know What You Think

After running a scan, use the Share Report button to get a link you can post to Reddit, share with your team, or attach to a GitHub issue or ticket.

We read every piece of feedback. If the scanner misses something, flags a false positive, or you want to see a check we have not built yet, use the rating widget on the tool page or reach out through the contact page. This tool improves because people tell us what they need. Run your free vulnerability scan