How I Hacked My College - Part 3

This is the final part of the series and probably the most impactful one achieving Remote Code Execution (RCE).

More than finding vulnerabilities, this journey was about changing how cybersecurity was viewed within the college environment. In many educational institutions, security is often ignored until a serious incident occurs. My goal throughout this assessment was to demonstrate why proactive security matters before real attackers exploit these weaknesses.

I also want everyone reading this to understand how important data security really is. Whether it is a college, company, or third-party service provider, your personal information is often handled by multiple systems behind the scenes. If those systems are not secured properly, the consequences can be severe.

Remote Code Execution - Smart, But Not Enough

Remote Code Execution (RCE) is considered one of the most critical vulnerabilities in cybersecurity because it allows an attacker to execute commands directly on a target server without physical access.

During my testing, I started analyzing file upload functionalities across the college applications. One particular feature allowed users to upload profile pictures.

Naturally, the first thing I wanted to understand was how the upload mechanism validated files.

I initially uploaded a normal image to observe the request flow, file path behavior, and server responses. Once I understood how the functionality worked, I attempted to upload a server-side script file for testing purposes.

The application immediately returned a 403 Forbidden response, confirming that direct script uploads were blocked.

At that point, the objective shifted from exploitation to bypassing the upload validation mechanisms.

Understanding File Upload Filters

Modern applications generally use multiple layers of validation to prevent malicious uploads. The most common protections include:

• Blacklist-based filtering
• Whitelist validation
• Content-Type validation
• File size or content length validation

During testing, I identified that the application relied heavily on extension-based whitelisting.

Instead of uploading a file with a direct executable extension, I modified the filename structure to bypass the validation logic. Due to improper server-side handling, the application accepted the file upload successfully.

That single bypass allowed execution of server-side code and ultimately led to Remote Code Execution on the target system.

Once execution was confirmed, I established controlled access to the server environment to demonstrate the severity of the issue and document the impact for remediation.

The Bigger Lesson

What looked secure at first glance failed because validation was implemented only partially. Security mechanisms that rely solely on client-side checks or weak extension filtering are rarely sufficient against determined attackers.

This assessment reinforced an important lesson: Security is not about adding filters - it is about implementing validation correctly at every layer.

This concludes the complete “How I Hacked My College” series.

Disclaimer: All testing activities were performed with proper authorization as part of a controlled security assessment. No sensitive information, credentials, or exploitable technical details have been disclosed in this article.

LinkedIn: https://www.linkedin.com/in/ashketchumwashere/

Instagram: https://www.instagram.com/ashketchumwashere/

X: https://x.com/ashketchum_16

Hope this helps you somewhere in your journey.

Thanks for Reading !!

./Keep_Hacking