Thank’s to some great effort put into the smb libraries by the folks over at nmap-dev, porting mbenum to Nmap wasn’t as hard as I’ve imagined. A first version has been committed to subversion a while ago but I forgot to publish this blog post at the time. Feel free to try it out! If you haven’t used mbenum before it’s a tool that allows you to get a good picture of a network by querying a single system.
Mbenum or the Nmap script smb-mbenum relies on being able to query the master browser for a particular domain or workgroup. You can find the master browser by sending a netbios query for the __MSBROWSE__ name. The Nmap script broadcast-netbios-master-browser can be used to identify the master browser for your broadcast domain by sending a netbios query to the broadcast address.