Virus Name: Chemnitz
V Status: Rare
Discovery: March, 1993
Symptoms: .EXE file growth; system hangs;
decrease in total system & available free memory
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,
Removal Instructions: Delete infected files
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:
Systems infected with the Chemnitz virus may experience system hangs
when .EXE programs are executed.