NetBIOS stands for Network Basic Input Output System. It Allows computer communication over a LAN and allows them to share files and printers.
NetBIOS names are used to identify network devices over TCP/IP (Windows). It must be unique on a network, limited to 16 characters where 15 characters are used for the device name and the 16th character is reserved for identifying the type of service running or name record type.
Attackers use the NetBIOS enumeration to obtain:
List of computers that belong to a domain
List of shares on the individual hosts on the network
Policies and passwords
Nbtstat: utility used to find protocol statistics, NetBIOS name table and name cache details
Superscan: GUI tool used to enumerate windows machine
Net view: command line tool to identify shared resources on a network