File path traversal, validation of start of path | Dec 12, 2022
Introduction
Welcome to my another writeup! In this Portswigger Labs lab, you’ll learn: File path traversal, validation of start of path! Without further ado, let’s dive in.
- Overall difficulty for me (From 1-10 stars): ★☆☆☆☆☆☆☆☆☆
Background
This lab contains a file 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.
Exploitation
Home page:
In the previous labs, we found that there is a file path trvaersal vulnerability in the display of product images:
Also, in the lab background, it said:
The application transmits the full file path via a request parameter, and validates that the supplied path starts with the expected folder.
To bypass that, we must go back to the / root file system:
/image?filename=/var/www/images/../../../etc/passwd
What we’ve learned:
- File path traversal, validation of start of path