Deaf Virus

Virus Name: Deaf Aliases: Deaf.1119, Stealth.1119 V Status: New Discovered: February, 1995 Symptoms: .COM & .EXE growth; file date/time year changed; decrease in total system & available free memory; DOS CHKDSK file allocation errors Origin: Unknown Eff Length: 1,119 Bytes Type Code: PRtAK - Parasitic Resident .COM & .EXE Infector Detection Method: F-Prot, ViruScan, AVTK, Sweep, IBMAV, VAlert, NAV, NAVDX, PCScan, ChAV, Sweep/N, AVTK/N, NShld, IBMAV/N, NAV/N, NProt, Innoc 4.0+ Removal Instructions: Delete infected files General Comments: The Deaf or Deaf.1119 virus was received in February, 1995. Its origin or point of isolation is unknown. Deaf is a memory resident stealth virus which infects .COM and .EXE files, including COMMAND.COM. When the first Deaf infected program is executed, this virus will install itself memory resident at the top of system memory but below the 640K DOS boundary, moving interrupt 12's return. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 7,168 bytes. Interrupts 21 and 24 will be hooked by the virus in memory. Once this 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 1,119 bytes with the virus being located at the end of the file. This file length increase, however, is hidden by the virus when it is memory resident. The file's date and time in the DOS disk directory listing will have the file date year altered so that it has a value between 20 and 39. No text strings are visible within the viral code. The DOS CHKDSK program, when executed with the virus memory resident, will indicate file allocation errors on infected files.