Virus Name: 1403
V Status: Rare
Discovery: October, 1993
Symptoms: .COM & .EXE growth;
Decrease in total system & available free memory
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,
Removal Instructions: Delete infected files
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.