While conducting a penetration test of a web application, the penetration tester enters the following URI: Which of the following attacks is the tester attempting?

XML injection involves manipulating XML input to exploit vulnerabilities in XML parsers, which is not what the `../etc/passwd` URI is designed to do.

SQL injection attempts to interfere with database queries through input fields, not by manipulating file paths in a URI to access system files.

The URI `.../etc/passwd` uses `../` sequences to navigate up the directory tree to access files or directories that are not intended to be publicly accessible, specifically targeting the `/etc/passwd` file, which is a common Linux system file containing user information. This technique is characteristic of a Directory Traversal (or Path Traversal) attack.

Buffer overflow attacks involve writing more data than a buffer can hold to overwrite adjacent memory, typically leading to crashes or arbitrary code execution, and are not initiated through a simple URI path manipulation like this.