The Path Traversal attack technique forces access to files, directories, and commands that potentially reside outside the web document root directory. An attacker may manipulate a URL in such a way that the web site will execute or reveal the contents of arbitrary files anywhere on the web server. Any device that exposes an HTTP-based interface is potentially vulnerable to Path Traversal.
Most web sites restrict user access to a specific portion of the file-system, typically called the “web document root” or “CGI root” directory. These directories contain the files intended for user access and the executables necessary to drive web application functionality. To access files or execute commands anywhere on the file-system, Path Traversal attacks will utilize the ability of special-characters sequences.