Security Check

Free Subdomain Takeover Risk Check

Detect dangling CNAME records that expose your subdomains to takeover. VP Shield checks your DNS against known vulnerable service fingerprints used in real attacks.

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What's Checked

  • CNAME record enumeration and resolution
  • Dangling CNAME detection
  • Known vulnerable service fingerprint matching
  • Risk severity classification
  • Affected subdomain listing
  • Remediation steps for each finding
  • Coverage of 50+ cloud and SaaS platforms
  • One-click re-scan after remediation

Common Questions

What is a subdomain takeover?
A subdomain takeover occurs when a DNS record points to a cloud resource that no longer exists. An attacker who can register or claim that resource can serve content from your subdomain. Browsers and users trust it as your domain, enabling phishing, cookie theft, and CSP bypass.
Which services are most commonly affected?
GitHub Pages, Heroku, AWS S3, Azure App Service, Shopify, Zendesk, Ghost, and Fastly are among the most commonly exploited. Any platform-as-a-service that uses customer-specific hostnames is potentially vulnerable if your CNAME points to a deleted resource.
How do I fix a subdomain takeover risk?
If the subdomain is no longer needed, delete the CNAME record from your DNS. If the service is still needed, recreate the resource at the same service with the same hostname, or migrate to a different approach. Do not just delete the cloud resource without also removing the DNS record.

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VP Shield checks DNS, TLS, email authentication, security headers, and subdomain takeover risk for any domain. Free, no login, two minutes.

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