Insecure Direct Object Reference (IDOR) represents a severe web application security vulnerability stemming from the exposure of internal object references without adequate access controls. Exploiting this flaw allows attackers to manipulate these exposed identifiers, such as database keys or file names, and gain unauthorized access to sensitive data or perform unauthorized actions. IDOR vulnerabilities have the potential to result in major security breaches, compromising the confidentiality, integrity, and availability of the application's data and functionality.
How it functions?
Insecure Direct Object Reference (IDOR) represents a critical security vulnerability commonly found in web applications. This vulnerability occurs when an application allows an authenticated user to access objects or resources directly without proper authorization. It arises due to the failure of the application to enforce proper access controls, resulting in unauthorized access to sensitive data or resources. IDOR occurs when user input is utilized to directly retrieve an object without validating the user's permissions. To mitigate the risk of IDOR vulnerabilities, developers must implement robust authorization checks to ensure that users have the necessary permissions before accessing sensitive objects or data.
Types of IDOR attacks.
- IDOR attacks come in two main forms: Body Manipulation and URL Tampering.
- In Body Manipulation, attackers modify form fields to access information from other users.
- URL Tampering involves tweaking parameters in the HTTP request to modify the URL and gain unauthorized access, with HTTP verbs GET and POST being particularly vulnerable.
How to identify IDOR vulnerabilities.
IDOR (Insecure Direct Object References) vulnerabilities are relatively straightforward to exploit but can be challenging for developers to detect. Unlike many other common security issues, automated tools such as code analysis and scanning may not effectively identify IDOR bugs. As a result, manual security testing may be necessary to pinpoint and address these vulnerabilities.
Some ways to identify vulnerabilities include:
• Performing basic tests using the built-in developer tools in a web browser
• Using a tool like Burp Suite or the Open Web Application Security Project Zed Attack Proxy (OWASP ZAP) to increase the effectiveness of manual testing
• Participating in a vulnerability disclosure program
• Hiring an external penetration testing firm to review critical web applications
How to prevent from IDOR Vulnerability.
- Implement robust access controls and validation mechanisms to prevent IDOR vulnerabilities and protect sensitive resources.
- Use complex identifiers and avoid exposing them in URLs and POST bodies.
- Pass identifiers in the session to prevent tampering in multi-step flows.
- Verify user's permission every time an access attempt is made.
- Replace enumerable numeric identifiers with more complex, random identifiers as a defence-in-depth measure.
- Use an Indirect Reference Map to avoid IDOR vulnerabilities by replacing actual references with alternate IDs that map to the original values
- Instead of using direct references in the URL, use indirect references and refer to the indirect reference map to look for the actual reference
- Validate user access by enforcing data layer access controls and performing syntactic validation on incoming inputs
- Apply criteria such as minimum or maximum length, bounds for numeric values, acceptable characters, and data type to ensure secure data handling