Lab: File path traversal, traversal sequences stripped with superfluous URL-decode

PRACTITIONER

This lab contains a path traversal vulnerability in the display of product images.

The application blocks input containing path traversal sequences. It then performs a URL-decode of the input before using it.

To solve the lab, retrieve the contents of the /etc/passwd file.

Solution

Use Burp Suite to intercept and modify a request that fetches a product image.
Modify the filename parameter, giving it the value:
..%252f..%252f..%252fetc/passwd
Observe that the response contains the contents of the /etc/passwd file.

Community solutions

Rana Khalil

Intigriti

z3nsh3ll

Michael Sommer

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