Monika-686 Virus

Virus Name: Monika-686 Aliases: Monika V Status: Rare Discovered: August, 1993 Symptoms: .COM file growth; file date/time changes decrease in total system & available free memory Origin: Unknown Eff Length: 686 Bytes Type Code: PRhCK - Parasitic Resident .COM Infector Detection Method: ViruScan, AVTK, Sweep, F-Prot, IBMAV, NAV, NAVDX, VAlert, ChAV, NShld, Sweep/N, NProt, AVTK/N, IBMAV/N, Innoc, NAV/N Removal Instructions: Delete infected files General Comments: The Monika-686 virus was received in August, 1993. Its origin or point of isolation is unknown. Monika-686 is a memory resident infector of .COM programs, including COMMAND.COM. It does not infect very small .COM files. When the first Monika-686 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 704 bytes. Interrupt 21 will be hooked by Monika-686 in memory. Also at this time, the virus will infect COMMAND.COM if it was not previously infected. Once the Monika-686 virus is memory resident, it will infect .COM programs when they are executed. Infected programs will have a file length increase of 686 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 have been updated to the current system date and time when infection occurred. No text strings are visible within the viral code in Monika-686 infected programs. It is unknown what Monika-686 does besides replicate.