Do you have the ZA suite installed, or just the firewall?
I wouldn't have thought that the free version of any firewall, for example, would create such a prompt.
Sality is not one to be trifled with, it's a polymorphic file infector. Hard to remove. Trashes stuff.
If ZA is genuinely prompting for an update, and you're certain it's a kosher source (does ZA have a user forum/could you google the prompt?) it should be good to update it.