Rosario Virus

Virus Name: Rosario Aliases: Rosario.1221 V Status: New Discovery: May, 1996 Symptoms: .COM file growth; decrease in available free memory Origin: Argentina 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 General Comments: 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: "Diego)es.NOB MOC.DNAMMOCE:\NOB_93.JPG" "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 disk.