Ok let's have a reality check.
Blocking archive files is easy by just writing a simple filter looking for
various extensions. Pruning executable files means you will have to use that
same filter, open the archive, either extract the whole thing, delete the
executables, and repackage the whole thing, or delete the executables in place.
Everyone can split large application files, or can be taught how, and send them
to be repackaged. Ever wonder how TCP and UDP work?
--- David J ONEILL <David.J.Oneill_at_state.or.us> wrote:
> Gee, why not just block ALL email communication. That would save you
> some work too.
>
> Archive files are a necessary part of communication and very beneficial
> in saving bandwidth.
>
> Let's have a reality check ....
>
> David J O'Neill
> Senior Systems Analyst
> State of Oregon
> Department of Human Services
> Office of Information Services
> PH# 503.378.2101 ext. 280
> email david.j.oneill_at_state.or.us
>
> >>> Jonathan Loh <kj6loh_at_yahoo.com> 03/14/05 02:21PM >>>
> Ok that's a solution. But what I want to ask you is this. How much
> overhead
> does it take to do this? Blocking archive files would be an easier
> method with
> little overhead. Possibly with a reply to sender that your site does
> not
> accept archive files.
> --- Kinnell <kinnell.t_at_gmail.com> wrote:
> > On the network I'm a member of we block all exe files sent inside
> the
> > rar or zip, so even if it is sent the file will be 0byted. Wouldn't
> > that be a better method? otherwise if you block all bz2, zip, rar,
> > etc... then you will block a lot of useful communication
> >
> > -Kinnell
> >
> > On Fri, 11 Mar 2005 16:49:16 -0500, adisegna_at_siscocorp.com
> > <adisegna_at_siscocorp.com> wrote:
> > > Sean, I have to disagree with you. Any file that that can
> encapsulate an
> > > executable file should be blocked (IMO). ZIP files are one of the
> > > biggest carriers of malicious content these days. I don't make it
> a
> > > habbit of trusting my users no matter how many times they get
> trained.
> > > RAR extraction tools are not part of the software image policy on
> my
> > > network so users are oblivious to the file blocking. What is your
> > > solution?
> > >
> > > Thanks
> > >
> > > AD
> > > Information Technology Group
> > > Security Identification Systems Corporation
> > >
> > > -----Original Message-----
> > > From: Sean Crawford [mailto:sean01_at_accnet.com.au]
> > > Sent: Tuesday, March 08, 2005 9:39 PM
> > > To: security-basics_at_securityfocus.com
> > > Subject: RE: 543.rar attachment
> > >
> > > ---> -----Original Message-----
> > > ---> From: adisegna_at_siscocorp.com [mailto:adisegna_at_siscocorp.com]
> > >
> > > ---> Subject: RE: 543.rar attachment
> > >
> > > ---> I just recently got the same executable inside .rar. I
> extracted
> > > the
> > > ---> dddd.exe and ran a scan on it. Norton Corporate 9.01 didn't
> find
> > > ---> anything (as of 4 days ago). I wasn't about to double click
> this
> > > exe on
> > > ---> my corporate network. Block the rar extension on your mail
> server.
> > > --->
> > >
> > > rar is a valid compression format...blocking it isn't a very good
> > > solution.
> > >
> > > 2 cents.
> > >
> > > Sean
> > >
> > >
> >
>
>
>
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Received on Mar 15 2005
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