Summary

  • A subdomain takeover occurs when a subdomain is pointing to a third-party service that is either unclaimed or deleted.
  • This creates a vulnerability where an attacker could claim the subdomain and host malicious content.
  • The attacker could then use this to their advantage for phishing, impersonation, or hosting dangerous malware and distributing it via the Domain Name System (DNS).
  • As examples, Ehtesham ul Haq discovered that Target had abandoned its sportsbook subdomain, which still pointed to Vercel, allowing ul Haq to claim the subdomain and point it at a phishing site.
  • Similarly, Shopify’s puncture subdomain, also pointing to Vercel, was abandoned, and attackers were able to hijack it.
  • These examples highlight the importance of ensuring that subdomains are properly managed and thatutherland is regularly carried out to ensure that third-party services are still in use.

By Ehtesham Ul Haq

Original Article