To fast on the trigger..
I don't want to start up the thread about AV on or not on the filers (I run it on my filer), but we got hit with a nasty variant of this. Not sure why Trend didn't block it, but basically a bunch of my CIF folders were set to read only/hidden.. Not fun. There are some other reasons that need to be mitigated that I wont go into, but this is the virus.
http://about-threats.trendmicro.com/Malware.aspx?id=47409&name=WORM_VOBF...
To unhide the share, we were mapped to the share location, and ran this.. It unhides the shares lick-ity split.
From an XP box..
Cmd
"usebackq delims=#" %i in (`dir *. /ah /s /b`) do attrib -s -h "%i"
Just share because I care..