Hi The!
22 Dec 96, letter The Visionary to Alexander Kovneristy:
 TV>        I would have to say that if every .EXE file was engineered to
 TV> CRC itself before execution, there would be no more .EXE infections,
 TV> since that in itself is a fairly solid form of self-checking (although
 TV> can be worked around, but not very easily).
    The most simple stealth method is to take int 21h fun. 4bh and to 
desinfect file before execution. Virus code get control before executable 
file itself, so self-checking will not find any changes. And at the end of 
the execution virus reinfects the file. It is very widespread stealth method.
                                    Dmitry Mostovoy
--- GoldED 2.50+
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