I don't know if it was the OSX update or a simultaneous Norton update that brought this on. But every Firewall dialog asking to block or allow connections are followed by a pop-up from SymUIAgent to enter my system password or cancel.
I think it is highly annoying. I found a post from August 2012 from a user with identical problem. No response to his post and no help to be found.
How do I make it stop?