A Guide To Subdomain Takeovers

### Executive summary This article is a practical guide on subdomain takeover vulnerabilities: it explains discovery methods (scraping, brute forcing, fingerprinting), notable tools (Sublist3r, SubFinder, Altdns, Massdns, EyeWitness), exploitation vectors and impacts (cookie scoping, CORS, OAuth callback whitelists, CSP bypasses, clickjacking, intercepted emails), automation workflows, and responsible reporting practices for safely demonstrating and disclosing findings.