Insecure Direct Object References (IDOR)
Insecure Direct Object References occur when an application exposes internal object identifiers in URLs or parameters without proper authorization checks, allowing attackers to access other users' data.
Insecure Direct Object References (IDOR) is an access control vulnerability that arises when an application uses user-supplied input to directly reference internal objects, such as database records, files, or API resources, without verifying that the requesting user is authorized to access the specified object. This is a subset of the broader Broken Access Control category and typically manifests in REST APIs, file download endpoints, and any functionality where resource identifiers like user IDs, order numbers, or document IDs are passed as parameters.
Why It Matters
IDOR vulnerabilities are deceptively simple yet devastatingly impactful. They are among the most commonly reported issues in bug bounty programs because they require no sophisticated tooling to exploit, just incrementing an ID in a URL can expose another user’s private data. In healthcare applications, an IDOR could expose patient medical records in violation of HIPAA. In financial platforms, it could grant access to other users’ account balances, transaction histories, or tax documents. The simplicity of exploitation means that IDOR flaws are often discovered and abused by unsophisticated attackers, script kiddies, or even curious users.
Consider an API endpoint GET /api/invoices/10432 that returns invoice details. If the server does not verify that the authenticated user owns invoice 10432, an attacker can iterate through invoice IDs and download every invoice in the system, a mass data exposure event.
How Revaizor Handles This
Revaizor’s AI pentesting platform excels at detecting IDOR vulnerabilities because its agents understand application context and user relationships. The platform creates multiple test accounts with different privilege levels and systematically attempts cross-account resource access across every API endpoint. Rather than simply fuzzing IDs, Revaizor’s agents map the authorization model and identify where access controls are missing or improperly enforced, including IDOR variants that rely on GUIDs, encoded values, or indirect references.
Related Terms
Cross-Site Scripting (XSS)
Cross-Site Scripting is a client-side code injection vulnerability that allows attackers to inject malicious scripts into web pages viewed by other users, enabling session hijacking and data theft.
Privilege Escalation
Privilege Escalation is the exploitation of a vulnerability or misconfiguration that allows an attacker to gain elevated access rights beyond what was originally granted, moving from low-privilege to high-privilege accounts.
SQL Injection
SQL Injection is a code injection technique that exploits vulnerabilities in an application's database layer by inserting malicious SQL statements into input fields or query parameters.
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