Night Virus

Virus Name: Night Aliases: Night.2048 V Status: New Discovered: July, 1995 Symptoms: .COM & .EXE growth; file date/time seconds = "62"; decrease in available free memory Origin: Unknown Eff Length: 2,048 - 2,062 Bytes Type Code: PRhA - Parasitic Resident .COM & .EXE Infector Detection Method: F-Prot, AVTK, VAlert, ViruScan, Sweep, IBMAV, NAV, NAVDX, ChAV, Sweep/N, NShld, IBMAV/N, AVTK/N, NAV/N, Innoc Removal Instructions: Delete infected files General Comments: The Night virus was received in July, 1995. Its origin or point of isolation is unknown. Night is a memory resident infector of .COM and .EXE files, but not COMMAND.COM. When the first Night 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. Available free memory, as indicated by the DOS CHKDSK program from DOS 5.0, will have decreased by 2,576 bytes. Interrupt 12's return will not be moved. Interrupt 21 will be hooked by the virus in memory. Once the Night virus is memory resident, it will infect .COM and .EXE files when they are executed. Infected programs will have a file length increase of 2,048 to 2,062 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 appear to be altered, though the seconds field will have been set to "62", the infection marker for the virus. No text strings are visible within the viral code. It is unknown what the Night virus may do besides replicate.