Virus Name: Vacsina
V Status: Common
Discovered: November, 1989
Symptoms: TSR; .COM, .EXE, .BIN, & .SYS growth; "beeps"
Eff Length: 1,206 bytes
Type Code: PRsA - Parasitic Resident .COM & .EXE Infector
Detection Method: ViruScan, F-Prot, AVTK, NAV, Sweep, IBMAV,
NAVDX, VAlert, PCScan, ChAV,
NShld, LProt, Sweep/N, Innoc, NProt, AVTK/N,
Removal Instructions: F-Prot, or delete infected files
The Vacsina virus is approximately 1200 bytes in length and can be
found in memory on infected systems. There are at least 48
variants of the Vacsina virus, also known as the TP virus family,
though not all of them have been isolated. Later versions of this
virus are included in this listing under the name "Yankee Doodle".
Generally, the Vacsina virus infects both .COM and .EXE files, as
well as .SYS and .BIN files. This virus, when infecting a .EXE
file, will first convert it into .COM format by changing the MZ or
ZM identifier in the first two bytes of the file to a JMP
instruction and then adding a small piece of relocator code, so
that the .EXE file can be infected as though it were originally a
One sign of a Vacsina infection is that programs which have been
infected may "beep" when executed. Infected programs will also
have their date/time in the disk directory changed to the date and
time they were infected.
Known variant(s) of Vacsina are:
TP04VIR: Infects .EXE files, changing them internally into .COM
files. Infected programs may beep when executed, and may
be identified by searching for the text string "VACSINA"
along with the second byte from the end of the file
containing a 04h. This version of Vacsina is a poor
replicator, and while it will always convert a EXE file
to .COM file format, adding 132 bytes, it does not always
infect executed files.
TP05VIR: Similar to TP04VIR, except that the second to the last
byte in the file is now a 05h. System hangs may also be
TP06VIR: Similar to TP05VIR, except the second to the last byte in
the file is now a 06h.
TP16VIR: Similar to TP06VIR, the second to the last byte in the
infected file is now 10h.
TP23VIR: Similar to TP16VIR, the second to the last byte in the
infected file is now 17h. The text "VACSINA" no longer
appears in the virus.
TP24VIR: Similar to TP23VIR, the second to the last byte in the
infected file is now 18h.
TP25VIR: Similar to TP24VIR, the second to the last byte in the
infected file is now 19h.
See: Penza Yankee Doodle