Viruses

[Jim Richards]

> >Yes,  it is possible for the machine to get a virus from just
> >saving to disk.  We had this problem before we installed McAfee's (we
> >were still on a Win 3.x network then).
> 
> I'm a little skeptical of this statement.
> 
> My understanding has been that there are two common infection mechanisms
> for PC code viruses: boot sector viruses, which infect your computer when
> you restart with an infected floppy disk in the drive, and viruses which
> infect executable files, like .EXE, .COM or .DLL files, and infect your
> computer when one of those infected executables is run on your computer.
> 
> These have been joined by macro viruses, which are executed by
> badly-designed Microsoft software (recent versions of Word and Excel) when
> infected documents are opened.
> 
> None of these mechanisms will infect a computer just by listing the files
> on a disk. (There are other varients; but I don't know of one that goes
> beyond these limitations.)
> 
> Going in the _other_ direction though, is fairly easy. Many viruses modify
> system files so they will be active on every reboot, and stay resident in
> memory and/or patch system routines. So once a computer is infected, it can
> and often will, infect every writable floppy put into the drive, even for a
> directory listing, and a file infector can infect any executable, not just
> those that have been run.
> 
> Until the advent of macro viruses, I think boot sector viruses were the
> most common. Both can spread from people just carrying around a disk of
> word-processor documents, as students and the like often do. Boot sector
> viruses  are to some degree independent of the OS (any Intel box can be
> infected); simple macro viruses without a code "payload" can run on Macs
> and PC.
> 
> On the other hand, unless you are a specialist in anti-virus support, you
> may not care about these details; commercial anti-virus software, updated
> several times a year, seems to be a lot more effective than anti-virus
> education: most people don't want to act paranoid enough to be safe without
> it.
> 
> If you manage something like a computer lab with public users, I'd invest
> in several virus scanners, and be prepared to restore systems from "clean
> backups".
> 
> 
> ---
>     Albert Lunde                      Albert-Lunde at nwu.edu
> 
> 
> 
> 

When this first happened, I too was sceptical since it went against 
everything I knew about viruses and how they work.  All of our 
stations' hard drives were completely marked as read-only. (except for 
files that HAD to be writtne to) Yet, I still found a virus on 3 out 
of 25 machines.  It was the exact same virus on each machine, sorry, 
I don't remember the name of it...

Anybody else every had an expierience like this?  I may very well be 
wrong about the whole thing...


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 Jim Richards
 Systems Administrator
 Naperville Public Libraries          Voice: (630)961-4100 x241
 200 W. Jefferson Ave.                    Fax: (630)961-4117
 Naperville, IL  60540-5351
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