Boot viruses
Boot viruses are some of the most successful viruses. They are simple to
write, and they take control of the computer at a low level.
What they infect: Boot viruses insert instructions into the boot sectors of
floppy disks, or the boot sector or master boot record
(partition sector) of a
hard disk.
How they infect: When the computer boots from an infected floppy disk, the
virus infects the hard disk and loads its code into
memory. The floppy disk does
not have to be bootable for the virus to spread. The virus remains memory
resident and infects
any floppy disks that are accessed. Typically, the trigger
for a boot virus is the system date or time. For example, the Michelangelo
virus
is a boot virus that deletes the hard disk of its host on March 6
(Michelangelo's birthday).
Damage: A bootable USB key, floppy disk or hard disk with an infected boot sector won't infect
any files unless the virus is also multipartite. A true
boot virus can't spread
to a server or over the network.
Examples: (to come)
(back)