DirBuster is described as 'Download DirBuster for free. DirBuster is a multi threaded java application designed to brute force directories and files names on web/application servers'. There are three alternatives to DirBuster for a variety of platforms, including Linux, Mac, Windows, Android and BSD. The best alternative is Dirstalk, which is both free and Open Source. Other great apps like DirBuster are Gobuster (Free, Open Source) and DIRB (Free, Open Source).