Does anyone know the source of this Apple II DOS 3.3 virus that infected my disks back in the 1990's? I got it from a public domain disk collection that was given to me by a friend, called the Freeloader Library, which was sold commercially in the back of computer magazines in the 1970s-80s.
Video of this Apple II virus in action: https://www.youtube.com/watch?v=rSgqX8ua2F8
There is no identifying information that I can find in the DOS hex code in memory, so I have no clue where this came from.
Method of operation:
- Boot from the viral DOS 3.3
- Insert a disk with some other DOS. Catalog it. Viral DOS checks to see if it is present on this disk. If not, then it overwrites the DOS and installs itself, and does a normal catalog.
Method of attack:
- After typing CATALOG 8 times, it zeroes the current target disk drive and modifies the reset vector so that you cannot break out of the destructive writing. Have to power off (for II/II+) or Control-OpenApple-Reset (IIe/IIc/IIgs) to regain control.
(This is one piece of software that I have no intention of uploading to Apple II disk archives to be preserved for future generations to experience.)