Lab: File path traversal, validation of start of path

PRACTITIONER

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

The application transmits the full file path via a request parameter, and validates that the supplied path starts with the expected folder.

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:
/var/www/images/../../../etc/passwd
Observe that the response contains the contents of the /etc/passwd file.

Community solutions

zenshell

Intigriti

Michael Sommer

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