Identification of Insecure Direct Object References (IDOR)

Insecure Direct Object References (IDOR) occur when an application provides direct access to objects based on user-supplied input. As a result, attackers can bypass authorization and access data and functionality that they shouldn't be able to access. Here's how a penetration tester identifies and evaluates the potential risks of IDOR vulnerabilities:

Steps for Identification

  1. Understanding Application Logic: The first step is to understand how the application processes and accesses objects. This includes understanding the request and response patterns, particularly how the application handles direct references to objects like files, database records, or other resources.
  2. Manipulate Direct Object References: Testers try to manipulate references (such as changing a parameter value in a URL or request) to access unauthorized data. For example, changing the id parameter in a URL from profile?id=123 to profile?id=124 to see if they can access another user's profile.
  3. Session Management Testing: Testers check if changing session-related information in cookies or request headers can lead to unauthorized access to other users' data.
  4. Authorization Testing: This involves testing whether the application properly enforces authorization checks when direct object references are accessed or manipulated.
  5. Automated Tools: While IDOR vulnerabilities often require manual testing to fully understand the context and potential impact, automated tools can sometimes help identify potential points of interest or unusual behavior when manipulating object references.

Common Examples of IDOR

  1. User Data Access: Changing a user ID in a URL or request to access or modify another user's data.
  2. File Access: Directly accessing files or other resources by changing a file name or path in a URL or request.
  3. Account Takeover: Manipulating parameters to access or take control of another user's account or data.

Implications of IDOR

  • Data Breach: Unauthorized access to sensitive data, leading to potential data breaches.
  • Privilege Escalation: Gaining access to functionalities or data intended for users with higher privileges.
  • Account Takeover: Taking control of another user's account, leading to further malicious activities.


  • Indirect Reference Maps: Use indirect references instead of direct references (e.g., instead of using the database ID, use a temporary, random, or hashed value that maps to the ID on the server side).
  • Access Control Checks: Ensure that each use of a direct object reference from a user includes an access control check to verify the user is authorized for the requested object.
  • Use of Frameworks: Utilize frameworks and libraries that abstract data access layers and enforce strict access controls.
  • Regular Testing and Audits: Conduct regular security testing and code audits to identify and fix IDOR vulnerabilities.

By identifying and addressing IDOR vulnerabilities, penetration testers play a crucial role in strengthening the security posture of applications, protecting them from unauthorized access and potential data breaches.