Virus Name: Qpis
V Status: New
Discovery: January, 1996
Symptoms: .COM & .EXE growth; decrease in available free memory;
unexpected errors on DOS DIR commands
Eff Length: 2,931 - 2,947 Bytes
Type Code: PRhAK - Parasitic Resident .COM & .EXE Infector
Detection Method: F-Prot, AVTK, IBMAV, NAV, NAVDX, ChAV,
Innoc, AVTK/N, IBMAV/N, NAV/N, NShld 2.33+
Removal Instructions: Delete infected files
The Qpis virus was received in January, 1996. Its origin or point
of isolation is unknown. Qpis is a memory resident infector of
.COM and .EXE files, including COMMAND.COM. It only infects files
located in the drive root directory.
When the first Qpis infected program is executed, this virus will
install itself memory resident at the top of system memory but
below the 640K DOS boundary, not moving interrupt 12's return.
Available free memory, as indicated by the DOS CHKDSK program from
DOS 5.0, will have decreased by 4,098 bytes. Interrupts 13 and 21
will be hooked by the virus in memory.
Once the Qpis virus is memory resident, it will infect .COM and
.EXE files located in the root directory, including COMMAND.COM,
when they are executed or opened, but not when copied. Infected
.COM files will have a file length increase of 2,931 bytes while
.EXE files will increase in size by 2,937 to 2,947 bytes. In both
cases, the virus will be located at the end of the file. The
program's date and time in the DOS disk directory listing will not
be altered. The following text strings are visible within the
This virus will interfer with the functioning of the DOS DIR
command, resulting in possible errors such as "Parameter format
not correct" and "Too many parameters"