Virus Name: MusicBug
Aliases: Music Boot, Music Bug
V Status: Common
Discovered: December, 1990
Symptoms: Decrease in total system and available free memory; clicking;
music randomly played on system speaker; lost clusters
Eff Length: N/A
Type Code: BRtX - Resident Boot Sector & Master Boot Sector Infector
Detection Method: ViruScan, F-Prot, NAV, AVTK, Sweep,
IBMAV, NAVDX, VAlert, PCScan, ChAV
Removal Instructions: See below
The MusicBug virus is a memory resident boot sector and master boot
sector (partition table) infector discovered in December, 1990. It
originated in Taiwan.
When a system is booted from a diskette infected with the MusicBug
virus, the virus will install itself memory resident at the top of
system memory but below the 640K DOS boundary. The interrupt 12
return will be moved, so 640K systems will now report 638K of
installed system memory. Clicking may be heard for a short time
from the system speaker before the boot proceeds, but more likely a
section of a tune will be played. The boot will then proceed.
Once MusicBug is memory resident, it will periodically play another
portion of the same tune when disk accesses occur. It is thus
When MusicBug is memory resident, any disk accessed (including the
system hard disk) will become infected with the virus. In the case
of hard disks, MusicBug infects the hard disk master boot sector and
Infected disks will have 4K in lost clusters which will contain the
virus's code as well as a copy of the disk's original boot sector.
The following text strings can also be found in these lost clusters:
"MusicBug v1.06. MacroSoft Corp."
"Made in Taiwan"
Diskettes infected with the MusicBug virus can be disinfected after
powering off the system and booting from a write protected system
diskette, then using the DOS SYS command. The lost clusters can
then be removed by using the CHKDSK command with the /F parameter.
Hard disks, however, cannot be disinfected in the same way. While
the DOS SYS command will remove the virus from the hard disk's boot
sector, and the lost clusters can be recovered, the hard disk will
remain an unbootable, non-system disk until a low-level format is