How to Scan a Website for Vulnerabilities

1. Confirm you are authorised to scan the website

Only scan a website, domain or internet-facing asset that you own, administer or have explicit permission to assess. Security testing can generate unusual traffic and may interact with systems in ways that normal browsing does not.

For a business-owned website, document the domain and any related assets that are in scope before you start. If a third-party provider hosts or manages the service, check any relevant acceptable-use or testing requirements as well.

2. Start with the external attack surface

External vulnerability scanning begins with what the internet can observe. That can include HTTPS and TLS configuration, browser-facing security headers, public DNS records, email-authentication records, reachable services and other exposed configuration.

This outside-in view is useful because it does not depend on the website dashboard looking correct. It shows how the service actually responds to a remote request at the time of the scan.

• Confirm HTTPS and certificate behaviour.
• Review common security headers and browser-facing controls.
• Inspect public DNS and domain configuration.
• Review SPF, DKIM and DMARC where the domain is used for email.
• Identify externally reachable services that warrant investigation.

3. Use automation to find areas that deserve review

An automated website vulnerability scan can cover repeatable checks quickly and consistently. That makes it useful for discovering configuration gaps, changes in external exposure and known classes of observable weakness.

Automation is not the same as proof of exploitability. A finding can be a clear configuration issue, an indicator that needs validation, or a low-risk observation whose significance depends on the website and business context.

4. Prioritise findings by risk and exposure

Review severity together with what the affected system does, whether it handles sensitive information, how exposed it is, and whether the finding can be independently confirmed. A public customer-facing service usually deserves different treatment from a low-impact informational endpoint.

Where a result points to a security header or public configuration issue, compare it with the intended application behaviour before changing production settings. Some controls need testing to avoid breaking legitimate website functionality.

5. Escalate when automated scanning is not enough

Automated external scanning cannot see every weakness inside application logic, source code, authenticated workflows, internal networks or business processes. For higher-risk applications, sensitive data, compliance requirements or findings that need validation, a scoped manual penetration test may be appropriate.

A penetration test uses human judgement and controlled exploitation within an agreed scope. Automated scanning supports that decision-making, but it does not replace a penetration test where one is required.

6. Re-scan after meaningful changes

A website is not static. Hosting migrations, plugin updates, DNS edits, certificates, integrations and new services can change the external attack surface. Re-scan after significant changes and consider scheduled monitoring if you need ongoing visibility rather than a single snapshot.