Responsible Disclosure: Browser DevTools and Direct File Access in SlidesGPT
Published: April 1, 2025
Introduction
Two months ago, a technical vulnerability was discovered and responsibly disclosed to the SlidesGPT team regarding how their presentation files are served to users. This post aims to discuss this disclosure transparently, now that the team has had adequate time to address the issue.
Understanding the Issue
SlidesGPT is an AI-powered presentation creation tool that helps users quickly generate slide decks. The service originally stored generated presentations in a Google Cloud Storage bucket with public access, making the files directly accessible through browser developer tools without requiring account creation or payment.
This unintentional setup created a situation where:
- Users could generate presentations using the service
- Inspect their browser’s network requests
- Identify and directly access the storage URLs for the generated files
- Download complete presentations without completing the intended signup or payment flow
Responsible Disclosure Timeline
- ~February 2025: The issue was identified and responsibly disclosed to the SlidesGPT team
- February-March 2025: The team acknowledged the report and began working on a solution
- April 2025: After the remediation period, this public disclosure is being made
Technical Explanation
The issue stemmed from a common implementation pattern where:
- Generated files were stored in cloud storage
- Direct links to these files were returned to the browser
- The frontend was responsible for enforcing access controls rather than backend authentication
This is a known vulnerability pattern sometimes referred to as “client-side authorization” where security checks happen in the browser rather than on the server.
Educational Takeaways for Developers
If you’re building web applications that serve user-generated content, consider these best practices:
- Implement server-side authentication for all protected resources
- Use signed URLs with expiration times for temporary access to cloud storage
- Audit network requests in your applications to understand what information is exposed
- Create proper access control layers between storage and public-facing interfaces
Resolution
The SlidesGPT team has now had sufficient time to implement proper access controls. As responsible members of the tech community, we should:
- Appreciate their work in addressing the vulnerability
- Understand that such issues are common in web development
- Learn from this case study to improve our own applications
Conclusion
This case highlights the importance of understanding web architecture and implementing proper access controls. By discussing these issues openly after responsible disclosure periods, we can collectively improve security practices across the industry.
Note: This post is intended for educational purposes only. Always respect terms of service for all web applications and services you use.