This is a simple Denial Of Service (DOS) attack, which exploits the WINS nameservice on port 137/UDP. You can take out WINS service by sending random shit to 137/UDP NETBIOS Name Service.
DoS.WINSKiller [Kaspersky]FDoS-Winskill [McAfee]security risk or a "backdoor" program [F-Prot]
winskill.exe