Why Automated Scanners Miss Most IDOR Flaws in Modern APIs

Security researchers warn that simple IDOR testing, such as swapping sequential integer IDs, misses most real business-logic access-control bugs. Modern APIs increasingly use UUIDs, opaque tokens, and nested GraphQL queries, which standard scanners are not built to exploit. The article describes several overlooked patterns, including GraphQL aliases that can bypass authorization checks, mismatches between UUIDs at the gateway and integer keys internally, and storage references that can yield access to another tenant's files. It also highlights batch endpoints that verify ownership of only one account ID rather than every object in the request. The authors conclude that IDOR is an architectural access-control problem, and recommend mapping how objects move across services and scrutinizing batch operations manually.