Doctor Qumak 2 Virus
Virus Name: Doctor Qumak 2
Aliases: Dr Qumak 2
V Status: Rare
Discovered: October, 1992
Symptoms: .COM file growth; decrease in total system & available free
memory; disk corruption; "Write protect error" messages
Origin: Krakow, Poland
Eff Length: 1,079 Bytes
Type Code: PRtCK - Parasitic Resident .COM Infector
Detection Method: AVTK, F-Prot, Sweep, ViruScan, IBMAV, ChAV,
NAV, NAVDX, VAlert, PCScan 5.02+,
Sweep/N, NShld, Innoc, AVTK/N, NAV/N, IBMAV/N
Removal Instructions: Delete infected files
The Doctor Qumak 2 virus was submitted in October, 1992. It is
originally from Krakow, Poland. Doctor Qumak 2 is a memory resident
infector of .COM programs, including COMMAND.COM. It is a
The first time a program infected with the Doctor Qumak 2 virus is
executed, this virus will install itself memory resident at the top
of system memory but below the 640K DOS boundary, moving interrupt
12's return. Total system and available free memory, as indicated
by the DOS CHKDSK program, will have decreased by 2,064 bytes.
Interrupts 12, 13, and 21 will be hooked by Doctor Qumak 2 in memory.
Once the Doctor Qumak 2 virus is memory resident, it will infect
.COM programs when they are executed or opened for any reason.
Infected programs will have a file length increase of 1,079 bytes
with the virus being located at the end of the file. The program's
date and time in the DOS disk directory listing will not be altered.
The Doctor Qumak 2 virus activates under two conditions, the first
condition being very destructive, slowly corrupting files on
infected systems. The virus keeps track of how many disk write
operations have occurred since it became memory resident. After
100 write operations have occurred, the virus will modify three
bytes in the next sector written to disk. After it has modified
50 sectors in this manner, it will display the following message:
"The famous cooperation strikes again: IT IS DOCTOR QUMAK II!
Watch out for the next virus from Kraków, Poland!"
This message is not visible within infected programs as it is
encrypted within the viral code.
The second condition under which Doctor Qumak 2 will activate is
during the months of April thru December of any year. During these
months, on Sundays after the 9th of the month, the virus will
simulate a "Write protect error" when the user attempts to write
to a diskette.