The Monkey virus was first discovered in Edmonton, Canada, in the year 1991. Monkey is one of the most common boot sector viruses. As the name indicates, Monkey is a distant relative of Stoned. Its technical properties make it quite a remarkable virus, however. The virus infects the Master Boot Records of hard disks and the DOS boot records of diskettes, just like Stoned.
Monkey spreads only through diskettes.
Monkey does not let the original partition table remain in its proper place in the Master Boot Record, as Stoned does. Instead it moves the whole Master Boot Record to the hard disk's third sector, and replaces it with its own code. When the computer is booted from the hard disk, the virus is executed first, and the hard disk can thereafter be used normally. The virus is not, therefore, easily noticeable, unless the computer is booted from a diskette. The fact that Monkey encrypts the Master Boot Record besides relocating it on the disk makes the virus still more difficult to remove.