Groz-999 Virus

Virus Name: Groz-999 Aliases: V Status: Rare Discovered: November, 1993 Symptoms: .COM & .EXE growth; decrease in total system & available free memory Origin: Unknown Eff Length: 999 - 1,096 Bytes Type Code: PRhAK - Parasitic Resident .COM &.EXE Infector Detection Method: F-Prot, AVTK, Sweep, ViruScan, NAV, NAVDX, VAlert, IBMAV, ChAV, Sweep/N, NShld, AVTK/N, NAV/N, IBMAV/N, Innoc 4.0+ Removal Instructions: Delete infected files General Comments: The Groz-999 virus was received in November, 1993. Its origin or point of isolation is unknown. Groz-999 is a memory resident infector of .COM and .EXE programs, including COMMAND.COM. When the first Groz-999 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. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 4,096 bytes. Interrupts 24 and 81 will be hooked by the virus in memory. Once memory resident, the Groz-999 virus will infect .COM and .EXE programs when they are executed. Infected programs increase in size by 999 to 1,096 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. One text string is encrypted within the viral code: "AIDSTEST" It is unknown what Groz-999 does besides replicate.