Introduction

As part of my dedicated journey into Cybersecurity, I have committed to documenting my progress and sharing my findings from various hands-on labs. Today, I am diving into the Race Conditions challenge on TryHackMe. For me, this isn't just about capturing a flag; it's about understanding the underlying logic of web vulnerabilities and refining my methodology as an aspiring Security Professional.

What I Learned: Understanding Race Conditions

Before jumping into the lab, I spent time researching the core concept. A Race Condition occurs when a system's behavior depends on the sequence or timing of uncontrollable events.

In web applications, this often happens when multiple requests are processed simultaneously, allowing an attacker to interfere with the database before the first operation is fully completed. Understanding this 'window of opportunity' is key to identifying this flaw.

Methodology & Tools

To tackle this challenge, I utilized a structured approach and the following tools:

  • Platform: TryHackMe (Web App Security Lab)
  • Tools: Burp Suite, firefox, Firefox Multi-Account Containers.
  • Target: http://MACHINE_IP:5000

Video Demonstration (Proof of Concept)

I believe in 'learning by doing.' I have recorded my entire exploitation process to visualize how the vulnerability is triggered and how the application responds under stress.

In this video, you will see me capturing the request, configuring the attack in Burp Suite, and successfully bypassing the intended logic.

Key Takeaways & Mitigation

Detecting race conditions from the business owner's perspective can be challenging. If a few users redeemed the same gift card multiple times, it would most likely go unnoticed unless the logs are actively checked for certain behaviours. Considering that race conditions can be used to exploit even more subtle vulnerabilities, it is clear that we need the help of penetration testers and bug bounty hunters to try to discover such vulnerabilities and report their findings.

Penetration testers must understand how the system behaves under normal conditions when enforced controls are enforced. The controls can be: use once, vote once, rate once, limit to balance, and limit to one every 5 minutes, among others. The next step would be to try to circumvent this limit by exploiting race conditions. Figuring out the different system's states can help us make educated guesses about time windows where a race condition can be exploited. Tools such as Burp Suite Repeater can be a great starting point.

list a few mitigation techniques

  • Synchronization Mechanisms: Modern programming languages provide synchronization mechanisms like locks. Only one thread can acquire the lock at a time, preventing others from accessing the shared resource until it's released.
  • Atomic Operations: Atomic operations refer to indivisible execution units, a set of instructions grouped together and executed without interruption. This approach guarantees that an operation can finish without being interrupted by another thread.
  • Database Transactions: Transactions group multiple database operations into one unit. Consequently, all operations within the transaction either succeed as a group or fail as a group. This approach ensures data consistency and prevents race conditions from multiple processes modifying the database concurrently.

This lab taught me that security is as much about logic and timing as it is about code syntax.

Closing & Networking

This documentation is a testament to my consistent growth in the field of Cybersecurity. I am actively learning, practicing, and preparing myself for professional challenges in Penetration Testing and Security Analysis.

I would love to connect with fellow enthusiasts and professionals! LinkedIn: [Panglima Izzal Haq] GitHub: [panglimaizza]