10 Free Tools to Check Your Website Security

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The 10 free tools to check your website security are useful when combined: Google Safe Browsing, VirusTotal, urlscan.io, Sucuri, and Quttera look for reputation, redirects, browser-visible threats, and remote malware signals, while SSL Labs, MDN HTTP Observatory, SecurityHeaders, WPScan, and Internet.nl examine TLS, headers, WordPress exposure, and broader standards.

A free website-security checker is a diagnostic snapshot, not a complete security audit. MDN explains that even an excellent Observatory grade cannot cover every security consideration, while active or intrusive testing can create load or violate terms without authorization. Use public checks for triage, obtain permission for deeper scans, and never treat one clean result as proof that a site is safe.

#	Preview	Product	Price
1		Web Application Security: Exploitation and Countermeasures for Modern Web Applications	$34.49	Buy on Amazon
2		The Web Application Hacker's Handbook: Finding and Exploiting Security Flaws	$25.27	Buy on Amazon
3		Grokking Web Application Security	$41.22	Buy on Amazon
4		Hacking APIs: Breaking Web Application Programming Interfaces	$42.55	Buy on Amazon

Key takeaways

• No single free scanner proves that a website is secure; the ten tools below inspect different layers, including reputation, malware indicators, TLS, HTTP headers, WordPress components, DNS, email, and routing.
• MDN HTTP Observatory is the current name for Mozilla’s former HTTP Observatory service; the broader Mozilla Observatory was sunset in October 2024.
• Google Safe Browsing, VirusTotal, urlscan.io, Sucuri SiteCheck, and Quttera are the most useful starting points when a URL may be malicious, redirected, defaced, or blacklisted.
• SSL Labs, MDN HTTP Observatory, SecurityHeaders, and Internet.nl review configuration and standards rather than server-side code, hidden backdoors, or business-logic vulnerabilities.
• WordPress administrators should add WPScan, review every flagged core, plugin, and theme version against official guidance, and scan only websites they are authorized to test.
• Public URL analysis can expose submitted links, page content, screenshots, cookies, redirects, or related metadata, so never submit URLs containing passwords, reset tokens, private documents, or customer data.

What are the 10 free tools to check your website security?

The ten tools are not interchangeable. The first five focus mainly on public reputation, malware signals, redirects, and browser-visible behavior; the next four focus on transport, HTTP controls, and broader standards; WPScan is specifically for WordPress.

What does each website security checker actually test?

1. MDN HTTP Observatory

MDN HTTP Observatory is best for reviewing browser-facing HTTP security controls. The service returns a score and grade and provides recommendations involving controls such as Content Security Policy, HTTP Strict Transport Security, and cookie-related protections. Read the MDN tests and scoring documentation to understand what a particular result measures.

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Use the current name, MDN HTTP Observatory, rather than calling the service the old Mozilla Observatory. MDN announced the move on July 2, 2024, and the former broader Mozilla Observatory—including its TLS and SSH components—was sunset in October 2024. The MDN HTTP Observatory launch announcement explains the transition.

An excellent Observatory grade is not proof that an application is secure. MDN explicitly explains that many security considerations are outside the tool’s scope, and the most appropriate configuration depends partly on the site’s architecture. The result is therefore a useful hardening checklist, not a vulnerability assessment, malware scan, or guarantee.

2. SecurityHeaders

SecurityHeaders provides a fast, understandable review of a site’s HTTP response headers. The service identifies controls including Content-Security-Policy, Strict-Transport-Security, Permissions-Policy, Referrer-Policy, X-Content-Type-Options, and X-Frame-Options, then explains which controls are present or missing. Its official overview of SecurityHeaders describes the service as a free assessment of modern website-security features.

SecurityHeaders is particularly useful when a developer or administrator wants to see the practical effect of a header change without reading raw response headers. The service’s FAQ says that its scanner presents a modern Chrome user agent and identifies itself with a static SecurityHeaders string. Header recommendations still require compatibility testing: a stricter policy can affect scripts, frames, images, or embedded third-party services.

A strong SecurityHeaders grade does not assess server-side code, authentication, dependencies, exposed ports or services, malware, or business-logic flaws. MDN HTTP Observatory and SecurityHeaders overlap substantially, so treat their results as complementary header reviews rather than two independent confirmations of overall security.

3. Qualys SSL Labs SSL Server Test

Qualys SSL Labs SSL Server Test is the specialist choice for examining a public server’s TLS configuration and certificate deployment. The SSL Server Test provides more detail than a browser padlock by examining supported protocols, certificate chains, key exchange, cipher configuration, and how certificates are deployed.

Use SSL Labs when visitors report HTTPS warnings, a certificate appears incomplete, older clients cannot connect, or an administrator wants to review protocol and cipher choices. The result can explain whether the problem is related to the certificate itself, the chain delivered by the server, or the server’s TLS settings.

TLS is only one security layer. A site can receive a strong SSL Labs result while still containing an exploitable plugin, insecure application logic, exposed credentials, a compromised administrator account, or malicious content. Pair the test with malware, reputation, CMS, and application checks.

4. Google Safe Browsing Site Status

Google Safe Browsing Site Status checks whether Google currently considers a URL dangerous. Enter the public domain or URL in the Google Safe Browsing Transparency Report to check Google’s current unsafe-site status. Google uses Safe Browsing to warn people about unsafe websites in Search and browsers.

This is one of the best first checks when a browser displays a red warning, search traffic suddenly falls, or visitors report phishing or malware alerts. A flagged result is a serious reputation signal, but it does not explain every compromised file or identify the full cleanup path.

A clean result is also limited. Google’s status can change, and a clean domain result is not a guarantee that every page, redirect, download, or future version of the site is safe. If compromise is suspected, inspect Google Search Console and server files as well as the public URL.

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5. VirusTotal URL analysis

VirusTotal URL analysis gathers multiple security-engine results and related historical context for a submitted URL. VirusTotal’s URL documentation describes URL objects containing fields such as categories, the last-analysis date, and per-engine analysis results. The report can reveal whether several vendors have identified the same URL or whether a single engine is reporting an unusual result.

Use VirusTotal as a second reputation view after Google Safe Browsing, especially when a URL redirects or vendors disagree. VirusTotal also documents a way to request a fresh URL analysis through its API; a previously stored report should not automatically be treated as a current scan.

Engine disagreement is normal enough to require interpretation. A detection can be a false positive, while an absence of detections does not prove that a page is safe. VirusTotal stores URL analyses and reports for later retrieval, so do not submit a confidential or private URL unless you understand the service’s visibility and handling model.

6. urlscan.io

urlscan.io behaves like a browser visiting a submitted URL and records what happens during the visit. According to the service’s about page, a scan can record contacted domains and IP addresses, requested resources, screenshots, DOM content, JavaScript observations, and cookies. That makes urlscan.io especially useful for investigating redirects, phishing pages, suspicious scripts, and unexpected third-party resources without opening the URL in your own browser.

The submission interface offers visibility choices called Public, Unlisted, and Private; the scanner interface notes that some controls are tied to commercial plans. Public scans can disclose the submitted URL and scan details. Treat a URL containing a password, reset token, signed download link, private document, customer identifier, or other secret as unsafe to submit.

urlscan.io shows browser-visible behavior, not everything happening on the server. The result is not a source-code review, a scan of authenticated areas, or a substitute for an authorized application assessment.

7. Sucuri SiteCheck

Sucuri SiteCheck is a free remote scanner for quickly checking public malware indicators, blacklist status, defacement symptoms, and certain website errors. Sucuri’s SiteCheck report describes the service as providing immediate insight into malware infections. An independent TechRadar review published September 20, 2022 also describes checks involving remote malware indicators, blacklisting, defacement, and website errors.

SiteCheck is a good triage tool when a site displays unexpected redirects, spam, defacement, browser warnings, or search blacklisting. Run it alongside Google Safe Browsing, VirusTotal, and Quttera rather than assuming that one clean report settles the question.

Remote scanners cannot see every server file, database record, account, or authenticated area. A clean SiteCheck result therefore does not rule out a hidden backdoor or a deeper compromise. If the evidence points to an infection, a server-side forensic review and backups verified as clean are more appropriate next steps than repeatedly submitting the homepage.

8. Quttera Website Malware Scanner

Quttera is useful as a second opinion when malware, suspicious scripts, redirects, or blacklist problems are suspected. Quttera describes its free scanner as supporting malware detection, blacklist monitoring, external and server-side scanning, and heuristic analysis on its website malware scanner page.

Quttera’s URL Scanner documentation describes recursive downloading and behavioral analysis intended to identify malicious scripts, exploits, shell code, and suspicious executable content embedded in otherwise legitimate web content. Those capabilities make Quttera useful for finding signals that a header or TLS checker will never see.

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Interpret the result as triage. Heuristic tools can produce false positives and can miss novel, concealed, authenticated, or server-only threats. Confirm serious findings by examining server files, database changes, accounts, logs, and deployment history with the hosting provider or a qualified security professional.

9. WPScan

WPScan is the specialized choice for checking a WordPress site’s core, plugins, themes, and WordPress-specific exposure. The WPScan online scanner provides a free, instant report, while the broader platform maintains a continuously updated WordPress vulnerability database covering WordPress core, plugins, and themes.

WPScan’s documentation describes capabilities that can identify WordPress versions, plugins, themes, vulnerable components, exposed files, username enumeration, and other WordPress-specific issues. Review every flagged component against the official WordPress release information or the relevant plugin or theme vendor’s guidance. Do not assume that an old component is safe merely because the homepage loads normally.

WPScan has no useful role on a non-WordPress site. WordPress scanning also does not replace secure configuration, patch management, backups, least privilege, code review, or a full penetration test. WPScan’s online scanner asks users to confirm that they have permission to scan the site; obtain authorization before using any scanner that makes repeated requests or enumerates components.

10. Internet.nl

Internet.nl tests a broad set of modern Internet standards across web, email, DNS, routing, and connection behavior. Its main testing service and website-test documentation cover IPv6, DNSSEC, HTTPS, HTTP security headers, security.txt, DMARC, DKIM, SPF, STARTTLS, DANE, and RPKI across its website, email, and connection tests.

Use Internet.nl when the goal is broader standards conformance rather than just malware detection or application vulnerability discovery. The tool can expose gaps in domain, email, routing, and secure-transport practices that a malware scanner will not notice. Some tests may be especially relevant to European or standards-focused environments, but the underlying controls are broadly useful.

Internet.nl is not a malware scanner, source-code review, or application-vulnerability scanner. A good standards result should be combined with threat-reputation checks and, where authorized, deeper application testing.

Which tools should you use for a specific security concern?

Choose the first tool according to the question you need answered, then add a tool from a different layer. The following sequence avoids treating overlapping header grades or repeated reputation results as a complete audit.

How should you run the checks?

1. Record the exact target first. Note the domain or URL, the scan date, whether the URL redirects, and the exact finding or warning. Scanner results are time-sensitive, and a report for one URL may not describe another path on the same domain.
2. Start with reputation and browser behavior when danger is suspected. Use Google Safe Browsing, VirusTotal, urlscan.io, Sucuri SiteCheck, and Quttera. Do not visit a suspicious page in your normal browser merely because one service reports it as clean.
3. Review configuration separately. Use SSL Labs for TLS and certificate deployment, MDN HTTP Observatory and SecurityHeaders for HTTP controls, and Internet.nl for broader web, email, DNS, IPv6, and routing standards.
4. Add CMS-specific checks. If the website runs WordPress, run WPScan only with authorization and review every flagged core, plugin, and theme version against official release or vendor guidance.
5. Classify findings before changing production. A missing header may require compatibility testing; a TLS issue may require a certificate or server configuration change; a vulnerable WordPress component may require an update or removal; a malware signal may require containment and forensic work.
6. Remediate through the right party. Use the hosting provider for server and certificate issues, the CMS or component vendor for WordPress vulnerabilities, and a qualified security professional or incident-response provider when compromise is suspected.
7. Re-scan after the change. Run the relevant checks again, record the new date and URL, and compare the exact finding. A new clean result confirms only that the tool no longer sees that particular signal.

Can you scan a website without permission?

Do not actively or intrusively scan a website unless you have authorization from the operator. Repeated requests, component enumeration, or other active tests can create load, trigger defensive systems, violate terms, or cross legal and contractual boundaries. The WPScan online scanner specifically asks users to confirm that they have permission to scan the target.

Checking a public URL in a reputation service is different from testing an application. An authorized assessment may include deeper manual work, but the OWASP Web Security Testing Guide and its latest project documentation should be treated as testing guidance, not as permission to test someone else’s site.

Can public scanners expose the URL or page data?

Yes, public scanning can expose submitted URLs and scan artifacts, so private or tokenized URLs should not be submitted to public services. urlscan.io can record screenshots, DOM content, JavaScript observations, cookies, contacted domains, IP addresses, and requested resources. Its interface distinguishes Public, Unlisted, and Private visibility, with some controls tied to commercial plans.

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VirusTotal also stores URL analyses and reports for later retrieval. Remove passwords, reset tokens, signed download links, private documents, customer data, and other secrets from a URL before submitting it. When a private page must be assessed, use an authorized internal tool or security professional that can handle the data under the appropriate confidentiality terms.

What should you do after a scanner finds a problem?

Use the finding to choose a remediation path, not to buy another generic scan or assume that a single grade identifies the root cause. The correct next step depends on the layer that produced the result.

• For headers: review the specific recommendation in MDN HTTP Observatory or SecurityHeaders, make the change in the web server or application configuration, and test compatibility before deployment.
• For TLS: inspect the SSL Labs details for certificate-chain, protocol, key-exchange, and cipher problems, then work with the hosting or infrastructure administrator on the relevant certificate or server setting.
• For WordPress: review every flagged core, plugin, and theme version against official release or vendor guidance. Patch, replace, or remove vulnerable components, and verify that backups and administrator access are controlled.
• For malware or blacklisting: preserve the scan date, URL, redirect chain, and exact evidence. Check server files, databases, accounts, and logs with the host or a qualified responder; do not assume that a remote clean scan rules out a hidden backdoor.
• For preventive filtering: a website WAF can add a layer in front of the application, but a WAF does not prove that a scanner finding has been fixed. Cloudflare’s Free Plan information and its separate WAF setup guidance should be checked for current features and configuration requirements.

Site owners whose results show malware, blacklist warnings, redirects, or defacement may need website malware cleanup or managed website security rather than another public scan. Those paid services are separate from the free Sucuri SiteCheck result, and this article does not independently test or rank any cleanup provider.

For ongoing WordPress protection, Jetpack Protect and its support documentation describe WordPress malware and vulnerability scanning. A WordPress firewall such as Wordfence and the service’s malware-scanning documentation are alternatives to investigate. The article did not independently test either product, so neither mention should be read as a product recommendation or proof that it fixes a particular finding.

What these free tools cannot tell you

Free remote checkers generally cannot establish whether source code contains a logic flaw, whether an authenticated workflow can be bypassed, whether a database contains stolen data, whether an administrator account was compromised, or whether every server file is clean. MDN HTTP Observatory and SecurityHeaders focus on HTTP controls; SSL Labs focuses on TLS; Google Safe Browsing focuses on Google’s reputation signals; VirusTotal aggregates vendor intelligence; urlscan.io observes a browser-like load; Sucuri and Quttera inspect remotely visible malware indicators; WPScan focuses on WordPress; and Internet.nl evaluates broader standards.

That division of labor is the reason to combine results. A website with perfect headers can still be hacked. A website with strong TLS can still serve malware. A WordPress site with current components can still have a custom-code flaw or stolen credentials. A clean reputation report can become stale as soon as the page, redirect, account, or server changes.

For a deeper authorized review, use a recognized testing methodology such as the OWASP Web Security Testing Guide, or engage a qualified security professional. Automated free scans are valuable triage and hardening tools, but they are not a substitute for a complete security audit or penetration test.

Frequently Asked Questions

Does a clean website security scan prove that my website is safe?

No. A clean result from one free website-security checker only means that the checker did not detect a particular signal at that time. Combine reputation, browser-behavior, malware, TLS, header, CMS, and standards checks, and use authorized manual testing for deeper application risks.

Which free tool should I use if my website may be hacked?

Use Google Safe Browsing, VirusTotal, urlscan.io, Sucuri SiteCheck, and Quttera first when a URL may be malicious, redirected, defaced, or blacklisted. Do not enter credentials into the suspicious site simply because one scanner reports it as clean.

Are public URL scanners safe for private or tokenized links?

Do not submit private pages, passwords, reset links, signed URLs, private documents, or customer data to public scanners. urlscan.io can expose screenshots, DOM content, cookies, redirects, and related metadata, while VirusTotal stores URL analyses and reports for later retrieval.

Can I scan a website that I do not own?

Public reputation checks are not the same as authorized security testing. Obtain permission before using active scanners such as WPScan or any tool that makes repeated requests or enumerates components, because testing can create load, trigger defenses, or violate terms.

The Bottom Line

Use the ten free tools as a layered check: start with Google Safe Browsing, VirusTotal, urlscan.io, Sucuri, or Quttera for suspected threats; use SSL Labs, MDN HTTP Observatory, SecurityHeaders, and Internet.nl for configuration; and add WPScan for WordPress.

Record the date and exact finding, protect private URLs, obtain permission for active testing, remediate through the appropriate provider, and re-scan after changes. No clean result or high grade alone proves that a website is secure.

Quick Recap

SaleBestseller No. 1

Web Application Security: Exploitation and Countermeasures for Modern Web Applications

$34.49

SaleBestseller No. 2

The Web Application Hacker's Handbook: Finding and Exploiting Security Flaws

Comes with secure packaging; It can be a gift item; Easy to read text

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SaleBestseller No. 3

Grokking Web Application Security

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SaleBestseller No. 4

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