Avalon Virus

Virus Name: Avalon Aliases: Avalon.814 V Status: In The Wild Discovery: July, 1996 Symptoms: .COM & .EXE growth; decrease in available free memory Origin: Unknown Eff Length: 814 Bytes Type Code: PRhAK - Parasitic Resident .COM & .EXE Infector Detection Method: F-Prot, AVTK, IBMAV, ViruScan, ChAV, PCScan, NAV, NAVDX, Innoc, AVTK/N, IBMAV/N, NShld, NAV/N Removal Instructions: Delete infected files General Comments: The Avalon virus was received in July, 1996, and has been reported to be "in the wild" by at least one anti-viral researcher as of July, 1996. Its origin or point of isolation is unknown. Avalon is a memory resident infector of .COM and .EXE files, including COMMAND.COM. When the first Avalon 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 1,024 bytes. Interrupt 21 will be hooked by the virus in memory. Once the Avalon virus is memory resident, it will infect .COM and .EXE files, including COMMAND.COM, when they are executed. Infected files will have a file length increase of 814 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 the Avalon virus may do besides replicate.