I received warnings from Virgin by post about a Netbios vulnerability. So I took action.
I followed the advice from virgin and turned up the firewall setting on my Super Hub to medium. Great, except that my kids cannot now use Steam - much gnashing of teeth!
I tried the alternative of starting to create port blocking rules but it seems an enormous industry to me - I think I have to create rules for every device (3 laptops, 3 android phones, a nas drive, various tablets and gameboys) and, even then, that does not address the issue of friends coming round who link up to our network.
Any advice / help that gets me happy kids who can use steam and still be secure regarding netbios is much appreciated.
I'd check the NAS drive hasn't got any WAN sharing settings enabled as that is a common culprit.
Disclaimer - I don't work for Virgin Media. I'm just another VM user trying to help out so my answers may be wrong If my answer solves your problem please mark it as helpful as it may help others My setup: Vivid 200 Optical fibre with Superhub 2 in modem mode connected to a Netgear R7000 router. Telewest/VM user since 2001.