Article View: comp.virus
Article #4547Re: Checksumming
From: Y. Radai
Date: Mon, 17 Jun 1991 10:07
Date: Mon, 17 Jun 1991 10:07
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3128 bytes
Mike Lawrie writes:
> ... sooner or later this scenario [infecting
>files by performing SCAN while a virus like Plastique is in RAM] will
>re-occur, as you will get hit with a similar type of virus that McAfee
>has not yet catered for, even if you have their very latest version.
Right; I specifically stated that that could happen, and I mentioned
that in order to prevent such occurrences, you could add a good gene-
ric monitoring program. You didn't reply to that suggestion. But
actually, there is a surer solution which I mentioned only later on
in my posting, but which I should have mentioned here also: If you
want to be certain that such occurrences cannot occur, never run a
program like SCAN or a checksummer except when you are certain that
RAM is clean, i.e. only immediately after booting from a clean disk-
ette. (Authors of such programs should mention this; if they don't,
and that apparently includes McAfee, you have a legitimate gripe
against them.)
> A checksummer gives you no
>security whatsoever, because it does not prevent a viral infection.
True, a checksummer does not prevent infection, but at least it can
*detect* infections, and that's a lot better than no security at all!!
Knowing that certain files are infected, you can restore your files
from backups or use a disinfector, something which you wouldn't do if
the infections were not detected.
Moreover, if the checksummer is properly designed and implemented,
(1) it can detect *all* infections, and (2) it cannot be neutralized
or circumvented by hostile software. These are advantages that are
almost impossible to find in any other anti-viral software.
In my opinion, the best software solution is a *combination of
several* programs: a good checksummer (like V-Analyst), a good generic
monitor (like Secure), a known-virus scanner (too many to mention
names), a program which prevents infections through floppy boots (to
be mentioned soon), and more. I use all of them; the resident
programs don't take up much RAM, and they coexist peacefully (well,
most of them ...).
>Just that our experience that I wished to share was that with a
>checksummer in place and use of SCAN, you can end up with every last
>EXE/COM file on you hard disk looking very sick indeed.
Quite true ... *if* you don't take the proper precautions.
Y. Radai
Hebrew Univ. of Jerusalem, Israel
RADAI@HUJIVMS.BITNET
RADAI@VMS.HUJI.AC.IL
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!netnews.upenn.edu!vax1.cc.lehigh.edu!cert.sei.cmu.edu!krvw From: RADAI@HUJIVMS.BITNET (Y. Radai) Newsgroups: comp.virus Subject: Re: Checksumming Message-ID: <0001.9106181359.AA17901@ubu.cert.sei.cmu.edu> Date: 17 Jun 91 10:07:00 GMT Sender: Virus Discussion List <VIRUS-L@LEHIIBM1> Lines: 50 Approved: krvw@sei.cmu.edu