Directory traversal

- [Narrator] Another common web application security flaw … is the directory traversal attack. … This attack allows an attacker … to manipulate the file system structure on a web server. … Let's first talk about two important characteristics … of Unix file systems. … When using a Unix file system, … a single period references the current directory. … Using two periods references the directory one level up … in the hierarchy. … A directory traversal attack … uses these navigation references … to try to move up and down the directory structure … searching for unsecured files. … They work when an application allows a user … to request files stored elsewhere in the file system. … We're going to try one of these attacks … in the WebGoat environment. … First, here's a look at the file structure … to help you understand what's happening in the demo. … The ThreadSafetyProblem file is the one … that we're actually supposed to get … with the web application. … The tomcat-users file is the one …