Chemnitz Virus

Virus Name: Chemnitz Aliases: V Status: Rare Discovery: March, 1993 Symptoms: .EXE file growth; system hangs; decrease in total system & available free memory Origin: Unknown Eff Length: 767 - 781 Bytes Type Code: PRhE - Parasitic Resident .EXE Infector Detection Method: AVTK, F-Prot, Sweep, ViruScan, IBMAV, NAV, NAVDX, VAlert, PCScan, ChAV, Sweep/N, NShld, NProt, AVTK/N, NAV/N, IBMAV/N, Innoc, LProt Removal Instructions: Delete infected files General Comments: The Chemnitz virus was submitted in March, 1993. Its origin or point of isolation is unknown. Chemnitz is a memory resident infector of .EXE programs, and does not infect very small .EXE files. When the first Chemnitz infected program is executed, the Chemnitz virus will install itself memory resident at the top of system memory but below the 640K DOS boundary, hooking interrupt 21. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 848 bytes. Interrupt 12's return will not be moved. Once memory resident, the Chemnitz virus will infect .EXE programs, other than very small .EXE programs, when they are executed. Infected programs will have a file length increase of 767 to 781 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. The following text strings are visible within the viral code in all Chemnitz infected programs: "MsDos COMMAND" "FMCIKLMOFR|" Systems infected with the Chemnitz virus may experience system hangs when .EXE programs are executed.