Dangling DNS Records Can Outlive the Services They Point To
A hostname can remain part of an organisation’s public identity long after the application behind it has disappeared. The DNS record still resolves, certificates may have existed for years, links remain in old messages, and browser cookies may still be scoped broadly enough to include the name. Yet the external service named by that record may have been deleted and returned to a provider’s pool of available resources. That mismatch creates the conditions for subdomain takeover. The core problem is not DNS compromise. The authoritative zone can be operating exactly as configured. The failure sits between two control planes: DNS still delegates traffic toward an external platform, while the platform no longer associates the referenced resource with the domain owner.