-=> Quoting Curtis Canning to Rick Collins <=-
-=> FidoMail to 1:163/215, please.-=<
CC> So what about those viruses which activate at a certain time
CC> and date eg( Friday The 13th ) and many other famous viruses
CC> they are trojans and also they are viruses, and they aren't
CC> keeping you busy with a game or something while infecting your
CC> hard drive.
They are simply viruses, not trojans.  When they execute, they check
the date or time, or whatever for the "trigger" they are programmed
to use.  They then either execute the "payload" or not.  That's not a
trojan.
CC> My understanding of something that keeps you busy on something
CC> else while it infects or formats your hard drive is a Bomb of
CC> some sort.  ( Still is a trojan but the wrong type, not a virus
CC> dropper ).
Trojans often are not associated with "virus" activity at all, and
the really good ones don't provide _any_ obvious signs of their
activity, such as formatting a drive.  They are a different class
altogether from a "logic bomb".  There's no need to keep a user
"busy" while destroying his system, BTW.  That can be done with a
handful of instructions which execute in less than a second.
CC> Nothing is impossible, and if they do invent something
CC> like that, the person who programed it will be very rich,
CC> and it will change the virus industry and put the major
CC> virus companys out of business.
RC> Some things _are_ impossible.  You learn that with age.
cc> With money, man power and research, I thing that 99% of
cc> possibilities are possible. 
All "possibilities" are "possible", by definition.  Other things are
_not_ possible - no matter how much money you care to throw at it. 
There is no need to make programs "virus proof" when this can be
accomplished by proper design of the operating system, and a
conscientious applied security policy.  As long as the OS allows
access to low-level structures _no_ program can be "protected" as you
are suggesting.
CC> Then people would have to resort to programming bombs, instead
CC> of viruses.
RC> They don't _have_ to resort to anything.
CC> They are undetectible aren't they?
No, they're not.  But you'll have to define the term.
TTFN. Rick.
Ottawa, ON 9 Feb 11:51 
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