Virus Name: Rosario
V Status: New
Discovery: May, 1996
Symptoms: .COM file growth; decrease in available free memory
Eff Length: 1,221 Bytes
Type Code: PRhC - Parasitic Resident .COM Infector
Detection Method: ChAV, F-Prot, AVTK, IBMAV, ViruScan, NAV, NAVDX, PCScan,
Innoc, AVTK/N, IBMAV/N, NShld, NAV/N
Removal Instructions: Delete infected files
The Rosario or Rosario.1221 virus was received in May, 1996, and
appears to be from Argentina. It is a fast infector of .COM
files, but not COMMAND.COM.
When the first Rosario 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 4,112 bytes. Interrupt 21
will be hooked by the virus in memory.
Once the Rosario virus is memory resident, it will infect .COM
files other than COMMAND.COM when they are executed or opened,
but not when copied. Infected files will have a file length
increase of 1,221 bytes with the virus being located at the
beginning of the file. The program's date and time in the DOS
disk directory listing will not be altered. The following text
strings are encrypted within the viral code:
"Felicitciones su maquina esta infectada por el virus
LEPROSO creado por"
"J.P.G., hoy es mi cumpleanos y lo voy a festejar
formateando su rigido!!!"
"Bye...(Vamos Null que con Diego somos campeones)"
"CopyRight (C) 1993 hasta 2000, J.P.G., Rosario, Argentina"
This virus, under some circumstance, may format the system hard