MZV Virus

Virus Name: MZV Aliases: MZV.333 V Status: New Discovery: January, 1996 Symptoms: .COM file growth; decrease in available free memory Origin: Unknown Eff Length: 333 Bytes Type Code: PRhCK - Parasitic Resident .COM Infector Detection Method: ChAV, F-Prot, AVTK, IBMAV, ViruScan, NAV, NAVDX, Innoc, AVTK/N, IBMAV/N, NShld, NAV/N Removal Instructions: Delete infected files General Comments: The MZV or MZV.333 virus was received in January, 1996. Its origin or point of isolation is unknown. MZV is a memory resident infector of .COM files, including COMMAND.COM. When the first MZV 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 1,024 bytes. Interrupt 21 will be hooked by the virus in memory. Once the MZV virus is memory resident, it will infect .COM files, including COMMAND.COM, when they are executed. Infected files will have a file length increase of 333 bytes with the virus being located at the end of the file. The program's date and time in the DOS disk directory listing will not be altered. The following text string is visible within the viral code: "MZV 2 !!!"