Open udp netbios ports.

[Entelin]

I have a client I am trying to convince to install a firewall, (eather
iptables or preferably cisco PIX). They have practicly every service
under the sun open, the only reason their tcp netbios ports are closed
is because cox filters them. The only reason I am having to convince
them of anything is because they have another linux tech working for
them and he is somehow convinced that they are completely secure "at the
deamon level" wrote a big email to my client saying they dident need to
install a firewall, or even close totaly unused ports on their box!
(they even had echo and chargen open before I at least convinced them to
close those ie: forged packet between echo and chargen = storm).
nevermind the two root exploits their sendmail is at risk for. and the
password sniffing of their login,telnet etc.. god..

ANYWAY sorry for that rant. back on topic I was wondering if I could do
anything with these udp ports in absence of the filtered tcp netbios
ports. ? as in gain any kind of access or DoS.

137/udp    open        netbios-ns              
138/udp    open        netbios-dgm             
139/udp    open        netbios-ssn             

Thanks :)