Virus Name: VHP
Aliases: VHP-348, VHP-353, VHP-367, VHP-435, VHP-757, VHP-776
V Status: Research
Discovered: July 1989
Symptoms: .COM growth; system hangs
Eff Length: 348 - 435 Bytes
Type Code: PNC - Parasitic Non-Resident .COM Infector
Detection Method: ViruScan, AVTK, F-Prot, NAV, Sweep, IBMAV,
NAVDX, VAlert, PCScan, ChAV,
NShld, LProt, Sweep/N, Innoc, NProt, AVTK/N,
Removal Instructions: F-Prot, or delete infected files
The VHP virus is actually a small group or "family" of viruses that
was discovered in Bulgaria in early 1990. There are currently four
identified variants to the VHP virus, with the VHP-435 variant
being the one with the most potential for spreading. These viruses
were originally based on the Vienna virus. The progression of the
variants shows each variant to be a slightly better replicator.
The VHP Viruses are:
VHP-348: This variant does not replicate due to bugs in the virus
code. If it did replicate, it would infect .COM files.
The virus's effective length is 348 bytes.
VHP-353: VHP-348 fixed so that it will infected COMMAND.COM,
increasing its size by 353 bytes. It does not infect other
.COM files. This variant is still buggy, and it will
occasionally hang systems when attempting to find a .COM
file to infect.
VHP-367: VHP-353 which will now infect .COM files besides
COMMAND.COM. Infected files increase in size by 367
bytes. Very rarely, this virus will reinfect an infected
.COM file. VHP-353 does not always infect a .COM file
when an infected program is executed, it will sometimes
not infect any .COM file, though it has in effect
immunized the file from infection. This effect is
probably a bug in this variant.
VHP-435: Isolated in July, 1989, this variant is 435 bytes in
length and is not destructive, all it does is spread.
VHP-435 will attempt to infect one file each time an
infected program is executed. COMMAND.COM and .EXE files
are not infected. After infecting all of the .COM files
on the current drive and directory, it will attempt to
infect drive C:. VHP-435 is the VHP-367 virus with some
modifications to make it less likely to be noticed.
VHP-757: Received in November, 1991, VHP-757 is a 757 byte
variant of the VHP group of Bulgarian Vienna variants. It
infects one .COM program, but not COMMAND.COM, each time
an infected program is executed. Infected files increase
in size by 757 bytes with the virus being located at the
end of the infected file. Replicated samples are typically
not very infectious, and rarely will they infect other
VHP-776: Received in November, 1991, VHP-776 is a 776 byte
variant of the VHP group. It is similar in behaviour to
the VHP-757 variant, though it will not infect the first
two .COM files in a directory.
See: Sicilian Mob Vienna VHP2