Perhaps I'm being overly cynical, but I'm struggling to see how this qualifies as an IDOR in the strict sense. While using UUIDs might reduce guessability, the real issue here is weak authentication, not insecure direct object references.

OWASP defines an IDOR as "an access control vulnerability that occurs when an application uses user-supplied input to access objects directly… without verifying the user is authorized for the target object" (OWASP Top 10 2021 – A01: Broken Access Control). But in this case, access to highly privileged internal functionality was granted simply by logging in with default credentials, no authorization bypass was needed because authentication was effectively absent.

This aligns more closely with CWE-1390: "Use of Default Credentials" and CWE-306: "Missing Authentication for Critical Function." The attacker was able to log in as a privileged user due to trivial credentials, and the lack of multi-factor authentication (MFA) further compounded the issue. Had MFA been implemented, or default credentials disabled, the ID enumeration would have been irrelevant. That makes it clear the real vulnerability lies in the authentication mechanism and not in how object references were structured.