How to test your website for security vulnerabilities?

To test your website for security vulnerabilities, combine several methods: run an automated vulnerability scanner against a staging copy of the site, check your TLS and HTTP security header configuration, audit your plugins and code dependencies against known vulnerability databases, analyse your custom code for unsafe patterns, and manually review the areas scanners miss, such as access control and business logic. No single tool finds everything, but together these layers catch the vast majority of common problems.

This article walks you through a practical testing process you can run yourself, from free online checks that take a few minutes to developer tools that fit into a build pipeline. It focuses on testing websites you own or are authorised to test, and on finding and fixing weaknesses before attackers do.

Before You Start: Permission and Safety

Only test websites and servers you own or have explicit written permission to test. Scanning someone else's site without authorisation can be illegal and will often get your IP address blocked.

Even on your own site, keep these precautions in mind:

• Test on staging where possible: Active scanners submit forms, follow links, and send unusual input. On a live site, that can create junk records, trigger emails, or slow the server down.
• Take a backup first: If a test does cause damage, you can restore quickly.
• Tell your host: Some hosting providers treat heavy scanning as an attack. Check their policy or let support know in advance.
• Watch for side effects: Scanners can lock accounts, fill up logs, or trip your own firewall. That is useful information, but plan for it.

Understanding the Types of Security Testing

Different testing methods look at your website from different angles:

• Vulnerability scanning (DAST): Dynamic Application Security Testing tools probe the running website from the outside, just as an attacker would, looking for known issues and misconfigurations.
• Configuration checks: Tools that grade your TLS setup, security headers, DNS, and exposed services.
• Software composition analysis: Checking your plugins, themes, and libraries against databases of known vulnerabilities.
• Static analysis (SAST): Scanning source code for unsafe patterns, such as unescaped output or SQL built from user input.
• Manual testing: A human reviewing logic, permissions, and workflows that tools cannot understand.
• Penetration testing: A structured, goal-driven assessment, usually by a specialist, that combines all of the above.

The sections below cover each of these in the order most site owners find useful.

Step 1: Run Quick External Checks

Start with free online tools that require nothing more than your domain name. They give you a fast overview of your public-facing configuration.

1. Qualys SSL Labs Server Test: Grades your TLS certificate, protocols, and cipher suites, and flags problems such as outdated protocol support or an incomplete certificate chain.
2. Security Headers (securityheaders.com): Reports which HTTP security headers you send and which are missing, such as Strict-Transport-Security, Content-Security-Policy, and X-Content-Type-Options.
3. Mozilla HTTP Observatory: Checks headers, cookies, redirects, and other browser security features, with explanations for each finding.
4. Sucuri SiteCheck: A remote malware and blocklist scanner that looks for visible infections, spam, and known blocklist entries.
5. Google Search Console: Under Security & Manual Actions > Security Issues, Google tells you if it has detected malware, hacked content, or social engineering on your site.

You can also check headers yourself from the command line:

curl -sI https://example.com

Look for HTTPS redirects, security headers, and anything that reveals too much, such as detailed Server or X-Powered-By version strings.

Step 2: Check Exposed Services and Ports

If you manage your own server, confirm that only the services you intend to expose are reachable from the internet. Nmap is the standard tool for this. Run it against your own server's IP address:

# Scan the most common ports and detect service versions
nmap -sV -T4 203.0.113.10

A typical web server should only show ports 80 and 443, plus SSH (often 22) if you use it. Anything else, such as a database port (3306 for MySQL, 5432 for PostgreSQL) or an admin panel, should usually be closed to the public or restricted by firewall rules.

For deeper TLS testing on your own server, testssl.sh provides a detailed report from the command line:

./testssl.sh https://example.com

Step 3: Scan WordPress With WPScan

If your site runs WordPress, WPScan is a dedicated scanner that identifies the WordPress version, themes, plugins, and known vulnerabilities associated with them. Vulnerability data requires a free API token from the WPScan website, which comes with a daily request limit.

# Install on macOS or Linux with Ruby available
gem install wpscan

# Scan for vulnerable plugins and themes on your own site
wpscan --url https://staging.example.com \
  --enumerate vp,vt \
  --api-token YOUR_API_TOKEN

The vp and vt options enumerate vulnerable plugins and themes. WPScan is also available as a Docker image if you prefer not to install Ruby.

From inside WordPress, security plugins such as Wordfence, Solid Security, and Patchstack can alert you when an installed plugin or theme has a known vulnerability, which gives you continuous coverage between manual scans.

You can also verify that core and plugin files have not been tampered with:

wp core verify-checksums
wp plugin verify-checksums --all

Step 4: Run a Web Application Scanner

General-purpose DAST scanners crawl your website and test for common vulnerability classes such as cross-site scripting, missing security headers, insecure cookies, and information disclosure.

OWASP ZAP

ZAP (Zed Attack Proxy) is a free, open-source scanner maintained by the ZAP project and widely used by developers and security professionals. The baseline scan is a good starting point because it is passive: it crawls the site and reports issues without sending attack payloads.

docker run --rm -t ghcr.io/zaproxy/zaproxy:stable \
  zap-baseline.py -t https://staging.example.com

Once you are comfortable with the results, ZAP's full scan runs active tests. Only run it against staging, since it submits forms and sends unusual input:

docker run --rm -t ghcr.io/zaproxy/zaproxy:stable \
  zap-full-scan.py -t https://staging.example.com

ZAP also has a desktop application with a graphical interface, which is useful for exploring results and manually testing individual requests.

Nikto

Nikto is a command-line scanner that checks for dangerous files, outdated server software, and common misconfigurations:

nikto -h https://staging.example.com

It is noisy and not stealthy by design, which makes it a good fit for testing your own staging environment.

Commercial Scanners

Tools such as Burp Suite Professional, Invicti, Acunetix, and Detectify offer more advanced crawling, authenticated scanning, and reporting. They are worth considering for business-critical applications or when you need regular reports for clients or compliance.

Step 5: Audit Dependencies and Extensions

Most websites are built largely from third-party code. Known vulnerabilities in that code are among the most common ways sites get compromised.

For WordPress, list your plugins and themes with their versions, and compare them against a vulnerability database:

wp plugin list --fields=name,version,update
wp theme list --fields=name,version,update

For custom applications, use your package manager's built-in audit tools:

npm audit
composer audit
pip-audit

For continuous monitoring, enable GitHub Dependabot alerts or a similar service on your repository so you are notified when a new vulnerability affects a package you use.

Step 6: Analyse Your Custom Code

If you or your developer have written custom plugins, themes, or application code, static analysis can catch unsafe patterns before they reach production.

PHP_CodeSniffer With WordPress Coding Standards

The WordPress Coding Standards include security sniffs that flag unescaped output, missing nonce verification, and unsanitised input. Install them in your project:

composer require --dev wp-coding-standards/wpcs dealerdirect/phpcodesniffer-composer-installer
vendor/bin/phpcs --standard=WordPress wp-content/plugins/my-plugin

Pay particular attention to warnings from the WordPress.Security sniffs, such as EscapeOutput, NonceVerification, and ValidatedSanitizedInput.

Semgrep

Semgrep is a fast, multi-language static analysis tool with community rules for PHP, JavaScript, Python, and more:

semgrep scan --config auto

Static analysis produces false positives, so review each finding rather than treating the output as a verdict.

What Unsafe Code Looks Like

It helps to know what you are looking for. Here is a vulnerable query that builds SQL directly from user input:

<?php
// Unsafe: user input is placed directly in the query.
$id      = $_GET['id'];
$results = $wpdb->get_results( "SELECT * FROM {$wpdb->prefix}orders WHERE id = $id" );

And the safe version using $wpdb->prepare():

<?php
// Safe: input is cast and passed through a prepared statement.
global $wpdb;

$id      = isset( $_GET['id'] ) ? absint( $_GET['id'] ) : 0;
$results = $wpdb->get_results(
    $wpdb->prepare(
        "SELECT * FROM {$wpdb->prefix}orders WHERE id = %d",
        $id
    )
);

Similarly, any value printed into HTML should be escaped with functions such as esc_html(), esc_attr(), or esc_url(), depending on context.

Step 7: Test Manually for What Tools Miss

Automated tools are excellent at finding known issues and obvious misconfigurations, but they struggle with logic and permissions. Spend some time testing these areas by hand on staging.

Access Control

• Log in as a low-privilege user, such as a subscriber or customer, and try visiting admin URLs directly.
• Change an ID in a URL, such as an order or invoice number, and see whether you can view someone else's data.
• Check that REST API endpoints do not return private data to logged-out users. For WordPress, visit /wp-json/ and review which routes are exposed.

Input Handling

• Enter a harmless marker, such as <b>test</b>, into forms, search boxes, and profile fields, and check whether it renders as bold text anywhere. If it does, output is not being escaped.
• Try a single quote character in search fields and URL parameters. Database errors in the response suggest unsafe query handling. Classic payloads like ' OR 1=1 -- illustrate the idea, but the goal is simply to see whether input is handled safely, not to exploit anything.

Authentication and Sessions

• Confirm that login attempts are rate-limited.
• Check that password reset links expire and cannot be reused.
• Verify that logging out actually ends the session.
• Inspect cookies in your browser's developer tools to confirm they use the Secure and HttpOnly flags, and a suitable SameSite value.

File Uploads

• Check that upload forms reject unexpected file types.
• Confirm that PHP files cannot be executed from the uploads directory.

Sensitive Files

Try requesting files that should never be public, such as /wp-config.php.bak, /.env, /.git/config, or /backup.zip. Each should return a 403 or 404 response, not the file contents.

Step 8: Prioritise and Fix the Findings

Testing produces a list of findings. Not all of them are equally important. Prioritise them by:

1. Severity: How much damage could an attacker do? Remote code execution and SQL injection come before a missing optional header.
2. Exploitability: Is a public exploit available? Does it require authentication?
3. Exposure: Is the affected component public-facing, or only reachable by trusted admins?
4. Data at risk: Does it affect personal, payment, or business-critical data?

Fix critical and high findings first, retest to confirm each fix, and document what you changed. Accept that some low-severity findings may be acceptable risks, but record the decision.

Step 9: Make Testing a Routine

Security testing is not a one-off event. New vulnerabilities are discovered constantly, and every update or new feature can introduce new issues. A reasonable rhythm for most sites looks like this:

• Continuously: Vulnerability alerts from a security plugin or Dependabot.
• Monthly: External checks and a WPScan or dependency audit.
• Quarterly or after major changes: A full DAST scan on staging and a manual review of key workflows.
• Annually or for high-risk sites: A professional penetration test.

You can also add scanners to your CI/CD pipeline so that every deployment runs static analysis, dependency audits, and a ZAP baseline scan automatically.

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FAQ: Testing Your Website for Security Vulnerabilities

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Conclusion

Testing your website for security vulnerabilities works best as a layered process. Quick external checks reveal configuration issues, WPScan and dependency audits catch known flaws in third-party code, DAST scanners like OWASP ZAP probe the running site, static analysis finds unsafe patterns in custom code, and manual testing covers the access control and logic problems that tools cannot understand.

Start small with the free external checks, then build up to scheduled scans on staging and automated checks in your deployment pipeline. Fix findings in order of real-world risk, retest every fix, and keep going on a regular schedule. Finding your own weaknesses first is one of the most effective things you can do to keep attackers out.