IDOR

IDOR / broken access control lets you access another user’s flag by changing an ID parameter.

A defensive web CTF where you patch the vulnerable source and the grader attacks your build: Secure the Login is fixed with parameterized queries, and Render & Plunder is sealed by binding SSTI input as render context plus adding an object-level authorization check to kill the IDOR.

A GraphQL vault chains a crackable HS256 JWT secret (the challenge name) for tier escalation with broken object-level authorization — the unreleased album is hidden from album(id) but leaks through the label→artists→albums path.