AntiCMOS is a typical boot sector virus infecting master boot sectors
on hard disks and boot sectors on diskettes.
The virus infects a hard disk only if the user tries to boot from an
infected diskette. If the hard disk is infected the virus infects
practically all diskettes that are used in the computer.
AntiCMOS.A has an activation routine that tries to modify the setup
information in the CMOS memory. AntiCMOS.B tries to play a tune.
Due a bug in the code, neither of these routines will probably
ever get to be executed.
AntiCMOS virus was first found from Hong Kong in January 1994.
It's now common all over the world.
The AntiCMOS.B variant contains a text string 'I am Li Xibin'.
[Analysis: Mikko Hypponen, F-Secure]