1403 Virus

Virus Name: 1403 Aliases: V Status: Rare Discovery: October, 1993 Symptoms: .COM & .EXE growth; Decrease in total system & available free memory Origin: Unknown Eff Length: 1,403 - 1,417 Bytes Type Code: PRhAK - Parasitic Resident .COM & .EXE Infector Detection Method: ViruScan, IBMAV, F-Prot, AVTK, Sweep, NAV, NAVDX, VAlert, PCScan, ChAV, LProt, NShld, Sweep/N, NProt, AVTK/N, IBMAV/N, NAV/N, Innoc Removal Instructions: Delete infected files General Comments: The 1403 virus was submitted in October, 1993. Its origin or point of isolation is unknown. 1403 is a memory resident infector of .COM and .EXE programs, including COMMAND.COM. When the first 1403 infected program is executed, the 1403 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 3,296 bytes. Interrupts 08, 12, 13, and 21 will be hooked by the virus in memory. Once the 1403 virus is memory resident, it will infect .COM and .EXE programs when they are executed. Infected .COM programs will have a file length increase of 1,403 bytes. .EXE programs will increase in size by 1,403 to 1,417 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. No text strings are visible within the viral code. It is unknown what 1403 does besides replicate.