The best way to download Mutillidae is through https://sourceforge.net/. An older version of the web application also exists on the Metasploitable 2 virtual machine (VM). If you're wondering what Metasploitable is, it is another virtual machine, filled with vulnerabilities for security professionals to test.

It's always better to get the latest version from SourceForge, at https://sourceforge.net/projects/mutillidae/:

To download it, all you need to do is click on the Download button, and you'll be ready for installation in both Windows and Linux. The latest version (at the time of writing this book) is 2.6; by the time you're reading, there will probably be a newer version, with more exciting functionalities. It's good to know that the owner of this application is always working on enhancing its features.