Definition
Insecure Direct Object Reference (IDOR) is a vulnerability where an attacker can access resources by altering a reference, like a URL or parameter, without proper authorization checks. This flaw arises when an application fails to verify if a user has permission to access a specific resource.How It Works
- 1The application uses an identifier, such as a number or name, to refer to an object directly in the URL or API parameter.
- 2An attacker modifies this identifier to access another object.
- 3The application does not verify if the user is authorized to access the new object, leading to unauthorized data exposure.
Key Characteristics
- Direct access to objects through unvalidated references.
- Absence of access control checks.
- Can involve URLs, cookies, or hidden form fields.
Comparison
| Concept | Description |
|---|---|
| IDOR | Direct object access without validation |
| Broken Authentication | Mishandling of user identity verification |
| Cross-Site Scripting (XSS) | Injection of malicious scripts into web pages |
Real-World Example
The 2019 First American Financial data leak (CVE-2019-14234) exposed 885 million real estate documents because IDOR allowed sequential document access through URL manipulation.Detection & Prevention
- Detection: Use tools like Burp Suite, OWASP ZAP, or nuclei to test for IDOR vulnerabilities by automating parameter tampering and observing unauthorized access.
- Prevention: Implement proper access controls by verifying user permissions before granting access to any resource.
Common Misconceptions
- Myth: IDOR is only a web application issue. Fact: It can occur in any system exposing object references.
- Myth: Secure URLs alone prevent IDOR. Fact: URL encryption does not replace access control checks.