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Simulations/Insecure File Upload

Insecure File Upload

Intermediate

This file upload endpoint has weak validation. Bypass extension checks and Content-Type validation to upload a web shell, then configure proper defenses.

Progress:
1
Double Extension Bypass
2
Content-Type Spoofing
3
Apply Full Protection
Security:
app.io/upload

File Upload

Server Processing
Filenamephoto.jpg
Content-Typeimage/jpeg
Magic BytesFF D8 FF E0

Challenges

1
Double Extension Bypass
Upload a PHP shell disguised with a double extension (e.g., shell.php.jpg) that bypasses the extension check.
▼ hints
2
Content-Type Spoofing
Bypass the Content-Type check by spoofing the MIME type while uploading malicious content.
▼ hints
3
Apply Full Protection
Enable full security and verify that both bypass methods are blocked.
▼ hints
How to fix insecure file uploads
Validate content, rename files, and store outside webroot
▼

Frequently Asked Questions