If I turn on OS X "Screen Sharing" (i.e., VNC access), my console log gets regular messages like the following:
screensharingd: Authentication: FAILED :: User Name: N/A :: Viewer Address: <random IP redacted> :: Type: VNC DES
These occur every few minutes, with varying, more or less random, IP addresses... Turning off screen sharing stops the attacks for a few minutes, but they usually restart within a little of while if restarting (which I do need!).
I am not particularly worried about the actual attack succeeding but should I be worried about excess network traffic and just filling up the log files with un-necessary crap? I would strongly prefer not to have to use any third-party software if possible.
My machine is behind a cable modem and Apple Time Capsule which does all the NAT stuff and forwards appropriate ports to this machine.
For what it's worth, under Mavericks /etc/hosts.deny doesn't seem to have any effect, but I understand that I could possibly use
(I've got a similar question about ssh attacks...)