on the moral prespective, it would be intruding on peoples systems, but most likely they would have to execute an attachment through email or other forms, otherwise a hole in the OS could be exploited creating a hacking issue. Now, what would be the problem, its only helping people, and its not `violating security and privacy` because it wont be recording or reporting anything. Also, maybe it could spread through p2p networks etc. taking on attributes of other files. Would you be pissed off if a `virus` got rid of a virus on your computer? if you would you should patch your system and not open attachments you are not sure about. wouldnt it have been nice if somebody destroyed melissa in its process so it didnt become such a pandemic? also, if it were to spread not through email but by tcp/ip remote connections, could it be equipped with a remote scanner to scan for the virus before it infects the system? maybe utilize nmap to scan for vulns, then have programmed responses and ways to get in through those vulns, then you would be reverse engineering of copyrighted content (maybe) and copyright infringement (maybe).