Website Security Audit Tools: Free and Paid Options

Security audit tools automate the detection of vulnerabilities that would take a human auditor hours or days to find manually. They scan your website for misconfigurations, outdated software, known vulnerabilities, and common attack vectors, producing reports that prioritise what needs fixing. No single tool catches everything, so a robust security audit uses several tools in combination — typically a mix of free scanning tools for surface-level checks and paid platforms for deeper analysis.

The tools below range from completely free browser-based scanners to enterprise-grade vulnerability management platforms. We have organised them by primary function so you can build a toolkit that matches your site's complexity and your budget. Whether you are running a WordPress blog or a custom web application handling financial transactions, there is a tool here for your needs.

SSL Labs

Qualys SSL Labs Server Test is the industry standard for evaluating your SSL/TLS configuration. It is free, requires no registration, and produces a detailed report in about 60 seconds. Enter your domain and SSL Labs tests your certificate validity, protocol support, key exchange, cipher strength, and known vulnerabilities like BEAST, POODLE, and Heartbleed.

The output is an overall grade from A+ to F along with a detailed breakdown of every aspect of your TLS configuration. An A+ rating requires a valid certificate, TLS 1.2 and 1.3 support with older protocols disabled, strong cipher suites only, HSTS enabled with a long max-age, and no known vulnerabilities.

Most sites we audit score a B or C on their first test. Common issues include supporting TLS 1.0 or 1.1 for backward compatibility, weak cipher suites included in the configuration, missing HSTS header, and short certificate chains. Each issue in the report links to documentation explaining the risk and the fix.

Run SSL Labs after any server configuration change, certificate renewal, or hosting migration. SSL misconfigurations can happen silently — your site appears to work fine over HTTPS, but the underlying implementation may have weaknesses that attackers can exploit. Bookmark the test URL for your domain and check it monthly as part of your security monitoring routine.

Security Headers

SecurityHeaders.com, created by security researcher Scott Helme, scans the HTTP response headers your site returns and grades your security header implementation from F to A+. The scan is instant, free, and requires only your URL.

The tool checks for Content-Security-Policy, X-Content-Type-Options, X-Frame-Options, Referrer-Policy, Permissions-Policy, and Strict-Transport-Security. Each header gets a pass or fail with an explanation of what it does and how to implement it.

Security headers are one of the most impactful security improvements because they are entirely server-side configuration — no code changes required. Yet the vast majority of websites fail to implement them. In our experience auditing hundreds of sites, over 70 percent score a D or lower on their first SecurityHeaders.com test.

The fix for most header issues is adding a few lines to your server configuration file (nginx.conf, .htaccess, or Cloudflare page rules). The SecurityHeaders.com documentation provides implementation examples for every major web server and CDN. Start with the easiest headers — X-Content-Type-Options and X-Frame-Options can be added in minutes — and work up to Content-Security-Policy, which requires more careful configuration to avoid breaking legitimate functionality.

Sucuri SiteCheck

Sucuri SiteCheck is a free remote scanner that checks your website for known malware, blacklisting status, injected spam, defacement, and other indicators of compromise. It also checks whether your site is listed on major blacklists including Google Safe Browsing, Norton Safe Web, Phishtank, Opera, and Yandex.

The scanner works by loading your site's public-facing pages and analysing the HTML, JavaScript, and iframes for known malicious patterns. It detects hidden spam links, malware download scripts, cryptocurrency mining code, phishing kit indicators, and SEO spam injections that redirect search engine visitors to malicious sites.

SiteCheck has limitations because it only analyses what is publicly visible. It cannot detect backdoors in your server files, compromised database records, or malware that only activates for specific user agents or IP addresses. Think of it as a health check that catches obvious infections but may miss sophisticated compromises.

Despite these limitations, SiteCheck is valuable as a quick first-pass scan and as a regular monitoring check. Run it weekly or set up Sucuri's monitoring service to scan automatically. If SiteCheck finds anything, investigate immediately — the issues it detects are typically active infections that are already affecting your visitors and your search rankings.

WPScan

WPScan is a specialised security scanner for WordPress websites. It maintains a comprehensive database of known WordPress core, plugin, and theme vulnerabilities — currently over 50,000 entries — and checks your site against it. If you run WordPress, WPScan should be part of every security audit.

The tool identifies your WordPress version, detects installed plugins and themes (including inactive ones that may still have vulnerable files), checks for default and weak credentials, tests for directory listing on sensitive paths like /wp-content/uploads/, and enumerates user accounts that could be targeted in brute-force attacks.

WPScan is available as a command-line tool (free and open source) and as a cloud-based service through WPScan.com. The command-line version is more powerful and flexible. The cloud version is easier to use and includes scheduled scanning. Both use the same vulnerability database, which requires a free API token that provides 25 API requests per day — sufficient for most small to mid-sized WordPress sites.

The most common findings in WPScan audits are outdated plugins with known vulnerabilities. WordPress sites typically have 15 to 30 plugins installed, and keeping all of them updated is a maintenance task that many site owners neglect. A single vulnerable plugin is often all an attacker needs to gain initial access. WPScan's vulnerability database includes links to advisories, CVE references, and remediation steps for every finding.

OWASP ZAP

OWASP ZAP (Zed Attack Proxy) is a free, open-source web application security scanner maintained by the Open Worldwide Application Security Project. It is one of the most widely used security testing tools in the world and is suitable for testing everything from simple websites to complex web applications.

ZAP works as an intercepting proxy — it sits between your browser and your web application, analysing every request and response. It can also spider your site automatically, discovering pages and parameters that other scanners miss. The active scan mode tests discovered pages and parameters for a wide range of vulnerabilities including SQL injection, cross-site scripting, server-side request forgery, remote code execution, path traversal, and security misconfigurations.

For beginners, ZAP's Automated Scan feature provides a one-click scan that spiders the target URL and runs a standard set of active and passive tests. The results are presented as alerts categorised by risk level (high, medium, low, informational) with detailed descriptions, evidence, and remediation advice for each finding.

For advanced users, ZAP offers scripting support, API access for CI/CD pipeline integration, authenticated scanning (to test behind login pages), fuzzing capabilities, and custom scan policies. You can configure it to test only specific vulnerability categories or to focus on particular areas of your application.

ZAP is a powerful tool but it requires caution. Active scans send potentially malicious payloads to your application, which could cause data corruption, trigger security alerts, or create unwanted records. Always run ZAP against a staging environment rather than your production site. If you must scan production, use passive scan mode only, which analyses traffic without sending attack payloads.

Qualys

Qualys is an enterprise-grade vulnerability management platform that offers both a free web application scanner and comprehensive paid solutions. The free Qualys FreeScan service provides up to three scans of a single URL and checks for OWASP Top 10 vulnerabilities, SSL/TLS issues, and common web server misconfigurations.

The paid Qualys Web Application Scanning (WAS) service is significantly more powerful. It provides continuous scanning, authenticated testing, API scanning, malware detection, and integration with vulnerability management workflows. Qualys WAS maintains a massive vulnerability signature database and updates it continuously as new vulnerabilities are discovered.

What sets Qualys apart from simpler scanning tools is its vulnerability management capabilities. It does not just find issues — it tracks them over time, verifies whether fixes have been applied, manages remediation workflows, and produces compliance reports. For organisations that need to demonstrate security compliance (PCI-DSS, SOC 2, ISO 27001), Qualys provides the documentation and audit trail that auditors require.

Qualys pricing is not publicly listed and varies based on the number of web applications, scanning frequency, and additional modules selected. Expect enterprise-level pricing starting at several thousand dollars per year. It is most cost-effective for organisations managing multiple web applications that need continuous vulnerability monitoring and compliance reporting.

Mozilla Observatory

Mozilla Observatory is a free web security scanner developed by Mozilla that evaluates your site's security configuration and assigns a score from 0 to 100 along with a letter grade. It focuses primarily on security headers and best practices for secure web deployment.

The scanner tests for Content-Security-Policy, cookies (Secure and HttpOnly flags), Cross-Origin Resource Sharing configuration, Referrer-Policy, Strict-Transport-Security, Subresource Integrity, X-Content-Type-Options, X-Frame-Options, and X-XSS-Protection. For each test, it provides a pass or fail result with a description of the security benefit and implementation guidance.

Mozilla Observatory also integrates third-party scan results from SSL Labs, Security Headers, and the Immuniweb Security Test, giving you a consolidated view of multiple scanning tools in a single interface. This makes it an efficient starting point for any security audit because you get multiple perspectives without visiting multiple sites.

The scoring is intentionally strict. Most sites score below 30 out of 100 on their first scan. A perfect score requires implementing every recommended security header with optimal configuration, which is aspirational for many sites. Do not be discouraged by a low initial score — focus on the highest-impact items first (HTTPS, HSTS, CSP) and improve iteratively.

Intruder

Intruder is a cloud-based vulnerability scanner designed for businesses that need continuous security monitoring without the complexity of enterprise tools like Qualys. It scans your websites, web applications, and internet-facing infrastructure for over 10,000 known vulnerabilities including OWASP Top 10, CMS-specific issues, SSL problems, and server misconfigurations.

Intruder differentiates itself through usability. The setup takes minutes — enter your target URLs, authenticate if needed, and start scanning. Results are presented in a clean dashboard that prioritises findings by severity and provides clear remediation steps. There is no need to interpret raw scanner output or understand security jargon. Each finding includes a plain-language explanation of the risk and step-by-step fix instructions.

The platform offers three main scan types. Network scan checks your external attack surface including open ports, outdated services, and known CVEs. Web application scan tests your site for OWASP Top 10 vulnerabilities, injection flaws, authentication weaknesses, and misconfigurations. Cloud connector scan integrates with AWS, Azure, and Google Cloud to check your cloud configuration for security issues.

Intruder runs continuous background scans and alerts you when new vulnerabilities are discovered, either in your infrastructure or when new CVEs are published that affect your technology stack. This proactive approach means you hear about vulnerabilities before attackers find them rather than during your next scheduled audit.

Pricing starts at approximately 172 USD per month for the Essential plan (monthly scans) and goes up to the Premium plan at approximately 287 USD per month (continuous scanning, emerging threat alerts, and compliance reporting). A 14-day free trial is available. For businesses that cannot justify an in-house security team but need regular vulnerability assessment, Intruder hits the right balance of capability, usability, and cost.

The ideal security audit toolkit combines several of these tools. Start with the free options — SSL Labs, Security Headers, Mozilla Observatory, and Sucuri SiteCheck — for a baseline assessment. Add WPScan if you run WordPress. Use OWASP ZAP for deeper application testing. Consider Intruder or Qualys for ongoing monitoring. If you want a professional team to run these tools and interpret the results, explore our security audit services.