Article demonstrates a CORS bypass technique by exploiting improper Origin header validation that uses simple string matching. An attacker can craft a malicious origin like "redact.com.attacker.com" to bypass validation checking if the origin contains the legitimate domain, allowing credential-based requests to steal user account data.
Advanced CORS exploitation techniques demonstrating two real-world cases: chaining XSS vulnerabilities with CORS misconfigurations to leak sensitive data, and bypassing CORS origin validation using special characters in domain names (particularly in Safari) to exploit wildcard subdomain whitelisting. The second technique leverages browser inconsistencies in domain validation to craft malicious origins like 'zzzz.ubnt.com=.evil.com' that pass CORS checks while resolving to attacker-controlled domains.