DOSVer Virus

 Virus Name:  DOSVer 
 Aliases:     2062 
 V Status:    Rare 
 Discovered:  August, 1993 
 Symptoms:    .COM & .EXE growth; file date/time seconds = 60; 
              decrease in total system & available free memory; 
              DOS CHKDSK file allocation errors 
 Origin:      Unknown 
 Eff Length:  2,062 Bytes 
 Type Code:   PRhAK - Parasitic Resident .COM & .EXE Infector 
 Detection Method:  AVTK, F-Prot, Sweep, ViruScan, IBMAV, NAV, 
                    NAVDX, VAlert, PCScan, ChAV, 
                    AVTK/N, NShld, Sweep/N, NProt, NAV/N, IBMAV/N, Innoc 
 Removal Instructions:  Delete infected files 
 General Comments: 
       The DOSVer virus was received in August, 1993.  Its origin or point 
       of isolation is unknown.  DOSVer is a memory resident infector of 
       .COM and .EXE programs, including COMMAND.COM. 
       When the first program infected with the DOSVer virus is executed, 
       this virus will install itself memory resident at the top of system 
       memory but below the 640K DOS boundary.  Total system and available 
       free memory, as indicated by the DOS CHKDSK program, will have 
       decreased by 3,072 bytes.  Interrupt 21 will be hooked by the 
       Once the DOSHunter virus is memory resident, it will infect .COM and 
       .EXE ograms, including COMMAND.COM, when they are executed.  Infected 
       programs will have a file length increase of 1,666 bytes with the 
       virus being located at the end of the file.  The file length increase 
       will be hidden by the virus when it is memory resident.  The 
       program's date and time in the DOS disk directory listing will have 
       been altered so that the seconds field is set to "60".  As a result, 
       the file time may "disappear" from some files in the DOS disk 
       directory listing.  No text strings are visible within the viral code. 
       Systems infected with the DOSVer virus may notice that the DOS CHKDSK 
       program will return file allocation errors on all infected programs. 

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