Insecure Direct Object Reference (IDOR) vulnerability stands as a significant concern for web developers and security professionals alike. This vulnerability, though often overlooked, can have severe implications if exploited by malicious actors. In this blog post, we will delve into the intricacies of IDOR, explore various scenarios where it might occur, and provide a step-by-step guide to testing and identifying this vulnerability.

An Insecure Direct Object Reference (IDOR) vulnerability occurs when an application provides direct access to objects based on user-supplied input. Objects, in this context, can refer to database records, files, application pages, and more. The vulnerability arises when attackers are able to bypass authorization and access these resources directly, without the necessary permissions.

The IDOR vulnerability is particularly concerning because it can lead to unauthorized access to sensitive information, such as personal data, financial records, or confidential documents. It essentially breaks down the barriers that are supposed to protect data, allowing attackers to reach into areas they should not have access to.

The first step in crafting a payload for an IDOR vulnerability is to identify points where object references may occur. This involves mapping out all locations in the application where user input is used to reference objects directly.

For example, consider a scenario where user input is used to access a specific database row. If the application takes the value of a parameter (such as a customer number) and uses it directly in a query to the database, it may be vulnerable to IDOR.

Next, the value of the parameter used to reference objects should be modified, and it should be assessed whether it is possible to retrieve objects belonging to other users or otherwise bypass…