Koko Virus

Virus Name: Koko Aliases: Koko.1783 V Status: New Discovered: October, 1994 Symptoms: .COM & .EXE growth; decrease in total system & available free memory Origin: Unknown Eff Length: 1,783 - 2,052 Bytes Type Code: PRhAK - Parasitic Resident .COM & .EXE Infector Detection Method: ViruScan, AVTK, Sweep, IBMAV, NAV, NAVDX, PCScan, F-Prot, PCScan, ChAV, NShld, NProt, Sweep/N, AVTK/N, NAV/N, IBMAV/N, Innoc 4.0+, LProt Removal Instructions: Delete infected files General Comments: The Koko or Koko.1783 virus was received in October, 1994. Its origin or point of isolation is unknown. Koko is a memory resident infector of .COM and .EXE files, including COMMAND.COM. When the first Koko infected program is executed, this virus will become 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 2,048 bytes. Interrupts 03 and 21 will be hooked by the virus in memory. Once the Koko virus is memory resident, it will infect .COM and .EXE programs when they are executed. Infected .COM files increase in size by 1,783 to 1,795 bytes while .EXE files increase in size by 2,042 to 2,052 bytes. In both cases, the virus will be 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 in all Koko infected files: "KoKo (1)" It is unknown what Koko does besides replicate.