From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: DJGPP viruses (Re: HELP! "invalid page exception"??)
Date: Thu, 16 Sep 1999 12:30:02 +0200
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On Wed, 15 Sep 1999, Damian Yerrick wrote:

> > Not true.  Every DJGPP program has a short real-mode stub prepended
> > to it.  As far as DOS (and DOS-based virus) is concerned, a DJGPP
> > program is a very short real-mode program with lots of data attached
> > to it.
> 
> But wouldn't this appended data confuse most viruses to
> high heck?

No, viruses are programs, and programs cannot be confused ;-).

Seriously, though: the stub usually confuses anti-virus software, not
viruses.  What viruses do is still infect the program, but when they
do, they usually overwrite the beginning of the COFF image, and the
program won't run anymore (the stub won't load it).  See section 6.7
of the FAQ for more about this.