[comp.virus] Mac Files

A2MP@PSUORVM.BITNET (Michael Perrone) (09/28/90)

>It is my belief that any file on the mac which is capable of
>displaying itself as an icon has executable code to do so.  If this is
>true, then ANY file is open to infection by a virus designed to take
>advantage of this.

Actually Paul, you are wrong.  It is the finder that is responsible
for displaying icons.  Macintosh files have 2 forks, a data fork, and
a resource fork.  Only a resource fork can have executable machine
code.  Each macintosh file also has 2 four byte fields, called the
Type and Creator.  All applications have type 'APPL'.  The finder uses
these fields to determine what icon to display for a file, and whether
a file is executable. Data files generally do not have a resource
fork.

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| Michael Perrone, Macintosh Programmer                                 |
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