This chapter describes how to create a virus or, more precisely, a worm that reproduces itself only using vulnerabilities in Web systems.
The CD-ROM that accompanies this book doesn't contain the source code of the worm. In the book, only a few fragments of the source code are given. They just demonstrate some of its functions. All these fragments contain bugs that make this code useless. A capable variant of this virus doesn't exist and has never existed. The code of this worm cannot be considered harmful because the worm cannot leave the computer. What's more, in any computer the worm can reproduce itself only a few times. The worm cannot do any damage to the system. In other words, I only demonstrate the theoretical possibility of creating such a worm; I don't create it as a capable program. All the code presented in this book is just the worm's unconnected fragments. Therefore, the code of the worm is of theoretical interest only.