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[>_] ROOM · Cybersecurity
File Upload Vulnerabilities
Master file upload vulnerabilities. Learn to bypass client-side validation, extension filters, and magic bytes to achieve Remote Code Execution (RCE) via web shells.
Room tasks
1What is a File Upload Vulnerability & Its Impact
2Bypassing Client-Side Validation
3Extension & MIME Type Bypass Techniques
4Uploading Web Shells for Remote Code Execution
5Magic Bytes & Content Sniffing Bypass
6File Upload RCE Lab Guide
Frequently Asked Questions
What is a file upload vulnerability?
It occurs when a web application accepts uploaded files without properly validating type, content, or destination. Attackers can upload scripts or web shells and run code on the server.
How do attackers bypass file upload filters?
Common tricks include changing the extension, spoofing the MIME type, adding magic bytes to the file header, or using double extensions. Weak client-side validation is also easy to skip with a proxy.
How do you secure file uploads?
Validate file type server-side, rename files, store them outside the web root, disable script execution there, and limit size. This free Codelivly room shows both the attacks and the fixes.