How to Perform a Website Security Audit: A Step-by-Step Guide

What Is a Website Security Audit?

A website security audit is a systematic review of your site's security posture — identifying vulnerabilities, misconfigurations, and weaknesses before attackers find them. It's not the same as a full penetration test (which involves active exploitation), but a thorough audit covers the most common attack surface.

This guide walks through how to perform a practical security audit on your own website.

Step 1: Reconnaissance — Know Your Attack Surface

Before you can audit security, you need to understand exactly what you're securing.

**Map all subdomains:** Use tools or services to enumerate your subdomains. Every forgotten subdomain (old staging environments, legacy apps, dev servers) is a potential entry point. Read our guide on [subdomain enumeration](/blog/what-is-subdomain-enumeration) for a full breakdown.

**Identify all technologies:** - What CMS are you running? (WordPress, Drupal, custom) - What frameworks? (React, Laravel, Django) - What third-party scripts are loaded? (analytics, chat widgets, payment processors) - What server software? (Apache, Nginx, IIS)

Browser developer tools, Wappalyzer, or automated scanners like [Yrzo AI](https://yrzoai.dev) can identify your tech stack quickly.

**List all input points:** Every place your application accepts user input is a potential vulnerability: - Contact forms - Search boxes - Login forms - File upload fields - URL parameters - API endpoints - Comment fields

Step 2: SSL/TLS Configuration

A valid SSL certificate is the bare minimum — but configuration matters too.

**Check:** - Certificate is valid and not expiring soon - HTTPS enforced site-wide (HTTP redirects to HTTPS) - No mixed content (HTTPS page loading HTTP resources) - Strong cipher suites — no SSLv3, TLS 1.0, or TLS 1.1 - HTTP Strict Transport Security (HSTS) header present

Test your SSL configuration at ssllabs.com/ssltest — aim for an A or A+ grade.

Step 3: HTTP Security Headers

Security headers are instructions your server sends to browsers that enable important protections. Many sites have none of these configured.

**Check for these headers in every response:**

`Content-Security-Policy` — Prevents cross-site scripting by defining which sources can load scripts, styles, and other resources.

`X-Frame-Options` — Prevents your site being embedded in iframes on other domains, blocking clickjacking attacks. Read more about [clickjacking](/blog/what-is-clickjacking-prevention).

`X-Content-Type-Options: nosniff` — Prevents browsers from MIME-type sniffing responses.

`Referrer-Policy` — Controls what referrer information is sent with requests.

`Permissions-Policy` — Restricts access to browser features (camera, microphone, geolocation).

Test your headers at securityheaders.com.

Step 4: Authentication Security

**Login page audit:** - Is there rate limiting? Try submitting the login form rapidly — you should be blocked after several failed attempts - Is MFA available and enforced for admin accounts? - Does the error message distinguish between "wrong username" and "wrong password"? It shouldn't — that leaks valid usernames - Is the password field autocomplete set appropriately? - Is there a CAPTCHA after failed attempts?

See our [full guide to securing login pages](/blog/how-to-secure-website-login-page).

**Session management:** - Session cookies should have `HttpOnly` and `Secure` flags - `SameSite=Strict` or `SameSite=Lax` to prevent CSRF - Sessions should expire after inactivity - Logout should fully invalidate the server-side session

Step 5: Input Validation Testing

Every input field needs testing for injection vulnerabilities.

**SQL Injection** — Try entering a single quote `'` in form fields, search boxes, and URL parameters. Error messages containing SQL syntax indicate vulnerability. Read [how to fix SQL injection properly](/blog/how-to-fix-sql-injection-properly).

**Cross-Site Scripting (XSS)** — Try entering `<script>alert(1)</script>` in input fields. If an alert pops, or the tag appears unescaped in the page source, you have an XSS vulnerability.

**Path Traversal** — In file download or include parameters, try `../../../etc/passwd` to test for directory traversal.

Don't stop at the UI — test your API endpoints directly using a tool like Burp Suite or Postman.

Step 6: Access Control Review

[Broken access control](/blog/what-is-broken-access-control) is the #1 OWASP vulnerability. Test it by:

- Creating two test accounts at the same privilege level - Performing actions as Account A that generate URLs or API requests referencing specific IDs - Replaying those requests while authenticated as Account B - Checking whether Account B can access Account A's data

Also test: - Whether admin paths (`/admin`, `/dashboard`, `/manage`) are accessible without authentication - Whether API endpoints enforce the same access controls as the UI

Step 7: Third-Party Dependencies

Your website's security is only as strong as its weakest dependency.

**Check:** - When was your CMS last updated? - Are all plugins and themes up to date? - What JavaScript libraries are loaded from CDNs? Are they pinned to specific versions? - Check loaded packages against known vulnerability databases (Snyk, npm audit, OWASP Dependency Check)

Supply chain attacks via compromised third-party scripts are a growing threat. Read our [supply chain attack guide](/blog/what-is-supply-chain-attack-website).

Step 8: Information Disclosure

Sites often leak more information than they should.

**Check for:** - Verbose error messages that reveal server software, database type, or file paths - Directory listing enabled — navigating to a folder URL shows its contents - Backup files accessible — `.bak`, `.old`, `backup.zip`, `database.sql` in web-accessible locations - `robots.txt` revealing sensitive paths (it's public — don't use it to hide things) - Source code comments containing credentials or internal URLs - Git repository exposed — try navigating to `/.git/config`

Step 9: Automated Scanning

Manual testing catches logic flaws and business-specific issues, but automated scanners efficiently cover common vulnerability patterns at scale.

[Yrzo AI](https://yrzoai.dev) runs automated security scans covering SQL injection, XSS, security headers, SSL configuration, subdomain enumeration, access control issues, and more — giving you a structured report of findings with remediation guidance.

Automated scanning complements manual testing — use both.

Step 10: Document and Remediate

Your audit is only useful if findings get fixed.

**For each finding, document:** - Vulnerability type and location - Severity (Critical / High / Medium / Low) - Evidence (screenshot, request/response) - Recommended remediation - Assigned owner and deadline

Prioritise by severity. Critical and High findings should be remediated within days, not weeks. Retest after fixes are applied to confirm they're resolved.

Key Takeaways

A website security audit doesn't require specialist knowledge to start — reconnaissance, SSL checks, header review, and input testing are all accessible with free tools and this guide. The most important thing is doing it regularly, not just once.

Start with an [automated security scan](https://yrzoai.dev) to baseline your current posture, then layer in manual testing for your specific application logic.