Skip to main content

Broken Access Control: Understanding IDOR for Beginners (2026 Guide)

Introduction

After learning vulnerabilities like SQL Injection and XSS, the next important concept in web security is Broken Access Control, specifically IDOR (Insecure Direct Object Reference).

According to the OWASP Top 10, Broken Access Control is one of the most critical security risks in modern web applications.

What is IDOR?

IDOR (Insecure Direct Object Reference) happens when a web application uses user-supplied input to directly access objects without proper authorization checks.

In simple terms, the application allows access to data by changing an ID without verifying whether the user has permission.

Simple Real-World Example

Your profile URL might look like:

https://example.com/my-account?id=1005

If you change it to:

https://example.com/my-account?id=1006

and you can view another user’s private data, then the application is vulnerable to IDOR.

Why IDOR is Dangerous

Data Exposure

Attackers can access sensitive information such as emails, phone numbers, and addresses.

Unauthorized Actions

Attackers may modify or delete other users’ data without permission.

Account Takeover

If sensitive actions like password reset or email change are exposed, attackers can take full control of accounts.

IDOR Testing Method

1. Identify Parameters

Look for:

  • id=123

  • /user/45

  • /api/orders/10

2. Intercept Request

Use tools like Burp Suite to capture HTTP requests.

3. Modify ID

Change values such as:

user_id=100 → user_id=101

4. Observe Response

  • 403 or 401 means secure

  • Access to other user data means vulnerability

How to Prevent IDOR

Proper Authorization Checks

Always verify whether the logged-in user has permission to access requested data.

Use UUID Instead of Sequential IDs

Instead of predictable IDs:

1, 2, 3

Use:

550e8400-e29b-41d4-a716-446655440000

Avoid Direct Object References

Use internal mapping instead of exposing database IDs directly.

Conclusion

IDOR is one of the most common and high-impact vulnerabilities in modern web applications.

Mastering IDOR will significantly improve your skills in bug bounty hunting, penetration testing, and web security.

SEO Keywords

  • IDOR vulnerability explained

  • broken access control tutorial

  • insecure direct object reference

  • how IDOR works in web security

  • bug bounty IDOR examples

  • OWASP access control

Final Note

Always practice ethical hacking only on authorized systems and learning platforms.

Labels:

Comments

Post a Comment

Popular posts from this blog

File Inclusion Vulnerabilities: Understanding LFI and RFI for Beginners (2026 Guide)

Introduction In this part of the cybersecurity series, we will explore a critical web vulnerability known as File Inclusion . File Inclusion occurs when a web application allows users to control which files are loaded or executed on the server without proper validation. This vulnerability can lead to sensitive data exposure or even full server compromise. What is File Inclusion? File Inclusion is a vulnerability where an application includes files based on user input without proper validation or restrictions. There are two main types of File Inclusion vulnerabilities: Local File Inclusion (LFI) Remote File Inclusion (RFI) 1. Local File Inclusion (LFI) LFI allows an attacker to access and sometimes execute files that are stored on the local server. How LFI Works Consider a website that loads pages using a parameter: https://example.com/view.php?page=contact.php If the application is vulnerable, an attacker can manipulate the parameter: https://example.com/view.php?page=../../../../etc/p...
Post a Comment
Read more

Ethical Hacking & Penetration Testing Roadmap (2026)

A Complete Beginner-to-Professional Guide Why Learn Ethical Hacking? In today’s digital environment, organizations constantly face cyber threats. Ethical hackers play a key role in identifying vulnerabilities before attackers can exploit them. This field offers: High demand career opportunities Continuous learning Multiple income streams (job, bug bounty, freelancing) Quick Overview of the Roadmap This roadmap is divided into 7 practical stages: Fundamentals Web Security Hands-on Practice Tools Mastery Real-World Testing Reporting Skills Specialization Stage 1: Fundamentals (Build Your Base) Before touching any hacking tools, you must understand the basics. Networking IP Addressing TCP/UDP DNS & HTTP/HTTPS Operating Systems Linux (essential) Windows basics Programming Python (automation) JavaScript (web understanding) Stage 2: Web Security (Core Skills) Focus on the most common vulnerabilities: SQL Injection Cross-Site Scripting (XSS) Broken Access Control (IDOR) File Inclusion SSR...
Post a Comment
Read more

WHOIS Lookup (2026): Uncovering Domain Ownership & Server Details

  Welcome to another segment of our Information Gathering series! In our previous post, we explored WhatWeb to identify a website's internal technology stack. However, to understand who is behind a website, when it was registered, or which company manages its infrastructure, we need a technique called WHOIS Lookup . WHOIS is a fundamental footprinting method used by penetration testers to gather domain-level intelligence. What is WHOIS? WHOIS (pronounced as the phrase "who is") is a query and response protocol used for querying databases that store the registered users or assignees of an Internet resource, such as a domain name or an IP address block. Essentially, it acts as a public directory providing details about domain ownership, registration dates, expiry dates, and authoritative name servers. Why is it Important for Ethical Hackers? For a security researcher, a WHOIS lookup is vital for several reasons: Ownership Identity: Identifies the person or organization ...
Post a Comment
Read more