Virus Name: Penza
V Status: Rare
Discovered: July, 1992
Symptoms: .COM & .EXE growth; message; decrease in total system and
available free memory; message
Eff Length: 700 Bytes
Type Code: PRhAK - Parasitic Resident .COM & .EXE Infector
Detection Method: F-Prot, Sweep, ViruScan, IBMAV, ChAV,
AVTK, NAV, NAVDX, VAlert, PCScan,
NShld, Sweep/N, Innoc, NProt, AVTK/N, NAV/N, IBMAV/N,
Removal Instructions: Delete infected files
The Penza virus was submitted in July, 1992. Its origin or point of
isolation is unknown. Penza is based on the Vacsina family of
viruses. It is a memory resident infector of .COM and .EXE programs,
The first time a program infected with the Penza virus is executed,
this virus will install itself memory resident at the top of system
memory but below the 640K DOS boundary. It does not move interrupt
12's return. Total system and available free memory, as indicated
by the DOS CHKDSK program, will have decreased by 2,288 bytes.
Interrupt 21 will be hooked by Penza in memory.
Once the Penza virus is memory resident, it will infect .COM and
.EXE programs, including COMMAND.COM, when they are executed.
Infected programs will have a file length increase of 700 bytes
with the virus being located at the end of the infected file. The
program's date and time in the DOS disk directory listing will
not be altered. No text messages are visible within infected
The Penza virus will occassionally display the following message
accompanied by a beep when programs are executed:
"Welcome to Penza!"
Penza doesn't appear to do anything besides display its message
Known variant(s) of Penza are:
Penza-1210: A 1,210 byte variant of the Penza virus, Penza-1210's
size in memory is 1,328 bytes, hooking interrupt 89.
Once resident, it infects .COM and .EXE programs when
they are executed, increasing their size by 1,210 to
1,225 bytes. 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. When this variant
is memory resident, will it occassionally display the
following message on the system monitor:
"Best wished from Penza!"
Origin: Unknown October, 1992.