Object References are identifiers used by applications to locate and manage data or resources. They are crucial for accessing specific data within a system but can also present security risks if not handled properly. These references can be in the form of database keys, file paths, URLs, or any other method used to identify and retrieve data.

• Direct Object References: These are direct identifiers used to access resources, such as a specific file or database record. For example, a URL like `https://example.com/file/123` might directly reference a file with ID `123`.
• Indirect Object References: These involve using intermediate identifiers that map to the actual object. For instance, a user might be given a token that references a file in a database, rather than the file’s direct ID.
• Predictable References: References that are sequential or easily guessable can be exploited by attackers to access unauthorized data. For example, incrementing a numeric ID to access different records.

• Insecure Direct Object References (IDOR): When applications use predictable or insecure direct references without proper authorization checks, it can lead to vulnerabilities where attackers gain unauthorized access to resources.
• Access Control: Proper access control is essential to ensure that object references cannot be used to bypass security mechanisms. This includes validating that the user requesting access has the necessary permissions for the object they are trying to access.

• Access Control Checks: Always implement robust access control mechanisms to validate that users have the appropriate permissions to access or modify the objects referenced.
• Obfuscation: Use non-predictable and obfuscated identifiers to make it more difficult for attackers to guess or manipulate object references.
• Input Validation: Sanitize and validate inputs to prevent unauthorized manipulation of object references through user inputs or URL parameters.

• https://owasp.org/www-community/attacks/Insecure_Direct_Object_References
• https://en.wikipedia.org/wiki/Object_references
• https://www.csoonline.com/article/3252904/what-is-insecure-direct-object-references-idor.html