IDOR Exploit: A Tale of Account Takeover

Muhammad Danial
2 min readMay 31, 2024


In today’s interconnected digital landscape, security vulnerabilities pose significant risks. One such vulnerability is the Insecure Direct Object Reference (IDOR), which can lead to severe consequences such as account takeovers. This article explores an IDOR exploit through a detailed case study, highlighting its impact and prevention strategies.

Background Information: IDOR is an access control vulnerability when an application exposes a reference to an internal object, such as a file, directory, or database key, without proper access controls. This flaw allows attackers to manipulate references to access unauthorized data.

The Case Study: A recent security assessment revealed a critical IDOR vulnerability in a web application. During the evaluation, it was discovered that user profile URLs were predictable and accessible by incrementing user IDs. Here’s how the issue was exploited:

  1. Discovery: An ethical hacker noticed that the URL displayed the profile information for user 123. By changing the URL to, the hacker could view another user's profile.
  2. Exploitation: The hacker wrote a simple script to iterate through user IDs and collect sensitive information, including email addresses, phone numbers, and account settings.
  3. Impact: This vulnerability allowed unauthorized access to the personal data of thousands of users, leading to potential privacy violations and trust issues for the web application.

Analysis: The primary reason for this vulnerability was the lack of proper access controls on the user profiles. The application should have verified the logged-in user’s permissions before serving the profile data. The incident underscored the need for robust security measures to prevent unauthorized access.

Prevention: To prevent IDOR vulnerabilities, developers should:

  • Implement proper access controls and authorization checks.
  • Use non-predictable, random identifiers for references.
  • Regularly conduct security assessments and code reviews.

Conclusion: The IDOR vulnerability case study highlights the importance of securing direct object references to prevent unauthorized data access. Organizations can mitigate the risk of such exploits and protect user data by implementing stringent access controls and conducting regular security audits. In the ever-evolving field of cybersecurity, staying vigilant and proactive is crucial to safeguarding digital assets.