The CD-ROM accompanying this book contains a few tasks that suggest you should investigate vulnerable test systems. Each task presents a test system and gives you data necessary to start investigation of the system.
Some tasks assume you know the source code of the system scripts; the other tasks don't. To make the process interesting, don't examine the source code if it isn't explicitly recommended in a particular task.
To solve a task, don't use vulnerabilities in scripts that are components of another task.
The goal of each task is to investigate the system, gain access to private data, find vulnerabilities, and exploit them. The goals are set in the tasks.