How about a 1 green tick over icon when all is good
2 yellow exclamaition mark over icon when maintenance needed
3 white question mark over icon when something is questionable
4 Red cross over icon when suspected malware found
or just make the standard icon steady for all good and flashing on and off for a problem, I quite like this idea flashing icon would catch your eye.
This could help define meaning for more people. Kind regards