Katvir Virus

 Virus Name:  Katvir 
 Aliases:     Katvir.623 
 V Status:    New 
 Discovered:  January, 1996 
 Symptoms:    .COM file growth; file date/time changes; message displayed; 
              decrease in available free memory 
 Origin:      Unknown 
 Eff Length:  623 Bytes 
 Type Code:   PRhCK - Parasitic Resident .COM Infector 
 Detection Method:  F-Prot, AVTK, IBMAV, NAV, NAVDX, ChAV, ViruScan, 
                    Innoc, AVTK/N, IBMAV/N, NAV/N, NShld 
 Removal Instructions:  Delete infected files 
 General Comments: 
       The Katvir virus was received in January, 1996.  Its origin or point 
       of isolation is unknown.  It is a memory resident infector of .COM 
       files, including COMMAND.COM. 
       When the first Katvir 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.  Total 
       available free memory, as indicated by the DOS CHKDSK program from 
       DOS 5.0, will have decreased by approximately 9,216 bytes. 
       Interrupt 21 will be hooked by the virus in memory. 
       Once the Katvir virus is memory resident, it will infect .COM files 
       when they are executed.  Infected files will have a file length 
       increase of 623 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 have been updated to the current system date and time 
       when infection occurred.  The following text strings are visible 
       within the viral code in all infected programs: 
           "Dzieciatka wylewaja niewinnie lzy" 
           "bo czuja nieszczescie" 
           "choc go nie pojmuja...  - KatVir by Warlock from III LO in 
       The last text string indicated above can be found at the very end 
       of all infected files. 
       This virus may display characters from system memory including the 
       above text strings when infections occur. 

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