(June 1, 2015 at 6:57 am)Alex K Wrote:(February 6, 2015 at 7:57 am)Aractus Wrote: A few years ago it was Norton (I think) antivirus that attacked a core Windows file on normal regular XP machines that had just had a Microsoft security update, and crippled millions of systems so they couldn't run. AVAST! modifies the bootscreen (unless you tell it not to), which is far more dangerous than modifying icons in a .dll file.
In computer science class, I wrote a program that replaced the windows 3.1 boot screen on the school computer with a funny meme of the vice principal, with two days delay, by patching the win.com. True story.
I did something similar with an early school Macintosh Lab using Apple Talk. It wasn't really a virus though, as at that time viruses weren't even really a thing, and very little trickiness was required. I mean, in some cases direct access to every computer in the network only requiring the ability to navigate.
Oh yeah, and all home computers at that time AFAIK had a Rom-->Ram OS dump, so you could actually rewrite parts of the operating system. My friend Nino and I had Coco IIs, and he ended up getting every game wiped that he was currently better than me at. Ahhh the good ol' days.