That is...very strange. I have no idea how you could get a message like that in your terminal, beyond the obvious that somebody was messing with you or you have some sort of a trojan/rootkit installed.
I don't see any picture though, did you forget to post the link to it?
By the way, I wouldn't say:
Symantec? That is for windows, not Linux, and I hate it
Symantec makes software for Windows, but it also reports on security vulnerabilities; which in the case of a portable application like Firefox, may well apply to all platforms the program runs on, not just Windows. For example, a recent buffer overflow found in Opera was present even in the Nintendo Wii version of the software, a product that is considerably far removed from it's PC counterparts.