Estimated Savings: CYVOCATE’s report helped prevent potential certification fraud & platform abuse exceeding $300,000+ by securing the integrity of user progress and assessments.

Introduction

One of the most common mistakes we encounter is trusting the client-side to enforce business logic.

In this engagement, we identified that the application trusted sensitive API responses for test progression. By modifying the response, we were able to bypass assessment requirements, effectively granting ourselves unauthorized progression and access to gated features.

Discovery Process

Step 1: Intercepting the API Response

During login, the application called:

GET /api/auth/me
{
  "isPythonTestCompleted": false,
  ...
}

This flag directly controlled whether the user had completed the required Python Test.

Step 2: Response Manipulation

Using Burp Suite, we intercepted and modified the response:

"isPythonTestCompleted": true

The application UI immediately reflected the test as completed, unlocking gated learning modules and progression steps.

Step 3: Impact Demonstration

• Bypassed Python test without actual completion.
• Gained unauthorized access to restricted features.
• Compromised the platform’s integrity, credibility, and trust.

Proof of Concept