1784 Virus

Virus Name: 1784 Aliases: V Status: Rare Discovery: November, 1993 Symptoms : .COM & .EXE growth; decrease in total system & available free memory Origin: Unknown Eff Length: 1,784 Bytes Type Code: PRhAK - Parasitic Resident .COM & .EXE Infector Detection Method: F-Prot, ViruScan, IBMAV, Sweep, AVTK, NAV, NAVDX, VAlert, PCScan, ChAV, NShld, Sweep/N, AVTK/N, NProt, Innoc, IBMAV/N, NAV/N, LProt Removal Instructions: Delete infected files General Comments: The 1784 virus was received in November, 1993. Its origin or point of isolation is unknown. This virus is a memory resident infector of .COM and .EXE programs, including COMMAND.COM. When the first 1784 infected program is executed, the 1784 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 2,304 bytes. Interrupt 21 will be hooked by the virus in memory. Also at this time, the virus will infect COMMAND.COM if it was not previously infected. Once the 1784 virus is memory resident, it will infect .COM and .EXE programs when they are executed or opened, but not when they are copied. Infected programs will have a file length increase of 1,784 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. No text strings are visible within the viral code. It is unknown what 1784 does besides replicate.