This module is a port of shinnai's script. You need a valid login, but even anonymous can do it as long as it has permission to call NLST.
To display the available options, load the module within the Metasploit console and run the commands 'show options' or 'show advanced':
Time is precious, so I don’t want to do something manually that I can automate. Leveraging the Metasploit Framework when automating any task keeps us from having to re-create the wheel as we can use the existing libraries and focus our efforts where it matters.
– Jim O’Gorman | President, Offensive Security