Unlocking Admin Privileges: How I Exploited an IDOR Vulnerability

Unlocking Admin Privileges: How I Exploited an IDOR Vulnerability

Hello, I’m Sahil More, an independent security researcher. I’m excited to share my latest findings with you through this blog. As this is my inaugural post, I’m eager to dive into the insights and discoveries I’ve made. I hope you find the information valuable and engaging.

One of the most intriguing vulnerabilities I’ve encountered as a security professional is Insecure Direct Object Reference (IDOR). This seemingly innocent flaw can allow attackers to access or modify resources they aren’t supposed to, like sensitive data or even admin accounts.

In this post, I’ll share a real-world IDOR vulnerability I discovered and exploited, demonstrating how something so simple can grant unrestricted access to the most privileged areas of an application.

Before diving into the specific scenario, let’s talk about IDOR. It occurs when a web application allows direct access to objects (like database records, account information, or other resources) using user-controlled input. If access to these objects isn’t properly restricted or validated, attackers can tamper with the input to gain unauthorized access.

IDOR vulnerabilities are shockingly common, especially in applications where developers trust user-supplied data and fail to validate it server-side. This can lead to massive security breaches, enabling attackers to manipulate requests and escalate privileges.

The Real-World Exploit: From User to Admin
Now, let’s get into the fun part: how I leveraged an IDOR vulnerability to jump from a normal user to an admin account in just a few steps.

Step 1: Logging in and Analyzing Requests
During a security assessment, I logged into the web application as a standard user and began inspecting traffic using Burp Suite, my go-to tool for capturing and manipulating HTTP requests. I wanted to see how the application managed user data and permissions.

I noticed something interesting: each time I accessed my profile, the server would send my username in the request parameters. It also sent a cookie flag called ckright=0, which seemed to represent my user’s privilege level (in this case, a regular user).

Step 2: The First Attempt – Changing the Username
My initial test was simple: I captured a request to view my profile and changed the username parameter in the request to that of an admin account. As expected, the server threw an error, saying I didn’t have permission to view that user’s details.

So far, so good—it seemed like the application was enforcing access control based on the username parameter.

Step 3: The Breakthrough – Modifying the Cookie Flag
However, one thing caught my eye: the ckright=0 cookie value. This flag likely indicated my privilege level, and I wondered what would happen if I changed it.
Using Burp Suite, I intercepted another request, this time modifying the ckright cookie from 0 to 1, which seemed like a value an admin account would have.

When I sent the modified request, the response shocked me. Instead of receiving another permission error, I was redirected to the admin dashboard—without ever providing admin credentials.

I had just gained admin access by simply changing a cookie flag in my browser.

What went wrong?

No Server-Side Validation: The server didn’t validate whether the ckright value was legitimate or tied to my actual account.

Client-Side Trust: The application trusted values from cookies, which can be easily manipulated by anyone with access to the browser.

The Impact of IDOR

IDOR vulnerabilities, while seemingly small, can lead to devastating consequences:

Full Admin Access: I was able to view and modify admin-level data, including sensitive user information.

Privilege Escalation: By exploiting this vulnerability, any attacker could escalate their privileges and gain control over the application’s core features.